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DEVELOPING A METHODOLOGY FOR
EVALUATING PRIVATELY OPERATED
TOLL ROAD PROJECTS USING
STOCHASTIC COST-BENEFIT ANALYSIS
Sae Chi
BE (Civil) (Hons)
Submitted in fulfilment of the requirements for the degree of
Doctor of Philosophy
School of Civil Engineering and Built Environment
Science and Engineering Faculty
Queensland University of Technology
2018
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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Abstract
In the project appraisal of a major road project, the host government acts as the
decision-maker. Addressing net impacts and risks to the community is crucial for the
host government to ensure that the benefits of a decision outweigh the costs. Cost-
Benefit Analysis (CBA) is conducted for major road projects for the purpose of
evaluation. It measures the net impacts of the project through monetisation of the
impacts. The outcome of CBA is represented as Benefit-Cost Ratio (BCR).
Tolls are generally treated as financial transfers in CBA. However, it is
questionable whether tolls should be treated as financial transfers when tolls are
collected by the private operator. Moreover, many toll road projects have complex
risk-sharing mechanisms that can be unique to each project. Depending on the risk-
sharing arrangement, a part of the risks can be shifted to the private operator. This
indicates that risk allocations need to be carefully considered in the evaluation of a toll
road project and the treatment of some impacts may need to be altered accordingly, to
properly reflect net impacts and risks to the community in the evaluation.
Reviewing previous studies revealed that limited studies have been conducted
regarding CBA for the purpose of evaluating toll road projects, a lack of empirical
assessment of risks in CBA, and a scarcity of investigation into the treatment of tolls
in CBA.
This study examines the impacts and the risks of a toll road project to the
community, in order to reflect them in CBA. A range of literature, including recent
academic literature and publications of Australian transport authorities are reviewed
to outline the potential barriers in evaluation of toll road projects. Previously
conducted CBA for major road projects are reviewed to highlight any limitations and
difficulties of the existing practices of CBA. A toll road project case and a toll tunnel
project case are synthesised on the basis of the overarching characteristics of recent
existing major road projects. This study uses the stochastic CBA by incorporating the
Monte Carlo simulation approach for the purpose of examining evaluations of toll road
projects. The Monte Carlo simulation is a well-established risk analysis tool. The
synthesised case is evaluated using the stochastic CBA, which represents its outcome
as stochastic BCR distributions. Risk profiles are developed using statistic inferences
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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on the basis of the stochastic BCR distributions. The perspectives of “toll as a financial
transfer” (TT) and “toll as an end-user cost” (TC) are considered. Tolls and other
payments that are often used in toll road projects, such as minimum revenue
guarantees, are examined while considering the perspectives, to determine the
movements of each payment. On the basis of the payment movements, treatments of
some impacts are altered in CBA to better reflect the net impacts and risks to the
community. Examination of the developed risk profiles across perspectives and
scenarios reveals whether the shift risk can be portrayed in the stochastic CBA.
Risk profiles of the synthesised cases across various risk arrangement scenarios
found that treating tolls as the cost to the community is a reasonable and valid
approach. Treatments of various impacts need to be carefully considered on the basis
of the risk-sharing arrangement of the project. Altering impacts appropriately in CBA
better reflects the shift of risk in the outcome risk profile. The outcome risk profile
illustrated the net impacts and risks to the community in an empirical manner using
the stochastic CBA. Various scenarios and perspectives can be examined by analysing
the shift of risk on the basis of the risk profile.
There have been limited studies with regard to CBA for a toll road project in
academic literature. Different perspectives have been studied for various financial
analysis, however are seldom studied using CBA. This study enhanced the knowledge
of CBA for a toll road projects and incorporated different perspectives in CBA.
Moreover, this study determined the appropriate treatment of tolls in CBA through the
considerations of perspectives, which is a significant contribution to academic study
and practices about CBA. The CBA methodology that is proposed in this study can
be implemented in the existing project appraisal process. A detailed framework of the
proposed methodology is developed and shown. The proposed methodology provides
the host government with an effective tool that can support their decision making on
the basis of the net impacts and risks to the community by solely evaluating the project
from the public perspective.
Future study can be conducted to investigate the impacts of using various
discount rates, incorporating ramp-up period, examining various concession
arrangements and payments using the proposed methodology. Additionally,
considering perspectives in the CBA of other types of projects, such as public transport
projects can further extend the knowledge of CBA.
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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Keywords
Cost-Benefit Analysis; transport economics; transport engineering; transport planning;
toll road project; project evaluation; project risk; Monte Carlo simulation; Public-
Private Partnership; community perspective
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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Table of Contents
Abstract ..................................................................................................................................... i
Keywords ................................................................................................................................ iii
Table of Contents .................................................................................................................... iv
List of Figures ....................................................................................................................... viii
List of Tables ............................................................................................................................ x
List of Abbreviations .............................................................................................................. xii
Principal Notation ................................................................................................................. xiv
Statement of Original Authorship ......................................................................................... xvi
Acknowledgements .............................................................................................................. xvii
Chapter 1: Introduction ...................................................................................... 1
1.1 Background .................................................................................................................... 1
1.2 Aim of this Study ........................................................................................................... 2
1.3 Scope and Definitions .................................................................................................... 4
1.4 Study Contributions and their Significance ................................................................... 5
1.5 Thesis Outline ................................................................................................................ 7
1.6 Summary ........................................................................................................................ 9
Chapter 2: Research Methodology ................................................................... 11
2.1 Methodology Framework ............................................................................................. 11
2.2 Literature Review ......................................................................................................... 12
2.3 Comparative Case Study .............................................................................................. 13
2.4 Incorporating Stochastic Approach in Cost-Benefit Analysis ..................................... 13
2.5 Synthesising Toll Road and Tunnel Project Cases....................................................... 14
2.6 Profiling Risk Using Benefit-Cost Ratio Distribution Drawn from Simulation .......... 14
2.7 Altering Project Impacts in the Cost-Benefit Analysis ................................................ 15
2.8 Proposed Methodology for Evaluations of Toll Road Projects .................................... 16
Chapter 3: Literature Review ........................................................................... 17
3.1 Project Evaluation for Public Good ............................................................................. 17
3.2 Measuring Impacts using Cost-Benefit Analysis ......................................................... 20 3.2.1 Impacts of Transport Facilities .......................................................................... 20 3.2.2 Cost-Benefit Analysis Background Theory ....................................................... 21 3.2.3 Critique of Cost-Benefit Analysis ...................................................................... 22 3.2.4 Wider Economic Benefits .................................................................................. 23 3.2.5 Discounting ........................................................................................................ 24 3.2.6 Sensitivity Analysis ........................................................................................... 25 3.2.7 Alternatives to Cost-Benefit Analysis ............................................................... 26
3.3 Risks and Uncertainties of Toll Road Projects............................................................. 26 3.3.1 Project Costs ...................................................................................................... 27
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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3.3.2 Traffic and Revenue Forecasts ...........................................................................28 3.3.3 Political Influences .............................................................................................29 3.3.4 Toll Pricing .........................................................................................................30 3.3.5 Risk Allocation ...................................................................................................31
3.4 Monte Carlo Simulation ...............................................................................................32
3.5 Summary .......................................................................................................................33 3.5.1 Research Gaps ....................................................................................................34 3.5.2 Recommendation ................................................................................................35
Chapter 4: A Review of Cost-Benefit Analysis Practices ............................... 37
4.1 The Study Cases ...........................................................................................................37 4.1.1 Non-Tolled Roads ..............................................................................................37 4.1.2 Toll Roads ..........................................................................................................38 4.1.3 Project Proponent and Owners ...........................................................................40
4.2 Economic Parameters ...................................................................................................42
4.3 Project Costs .................................................................................................................43
4.4 Project Benefits .............................................................................................................44 4.4.1 Travel Time Saving ............................................................................................44 4.4.2 Vehicle Operating Cost Saving (VOCS) ............................................................45 4.4.3 Crash Cost Saving (CCS) ...................................................................................46 4.4.4 Environmental and External Cost Saving (EECS) .............................................47
4.5 Residual Value ..............................................................................................................49
4.6 Sensitivity Analysis ......................................................................................................51
4.7 Selection of Preferred Option .......................................................................................53
4.8 Treatment of Tolls ........................................................................................................54
4.9 Discussion .....................................................................................................................54
4.10 Summary .......................................................................................................................58
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis ... 61
5.1 Cost-Benefit Analysis Calculation ...............................................................................61
5.2 Probability Distributions Used in this Study ................................................................63 5.2.1 Capital Cost of a Toll Road Project ....................................................................63 5.2.2 Case Dependent Input Variables ........................................................................64 5.2.3 Transport Cost Unit Price ...................................................................................64
5.3 Synthesising a Toll Tunnel Project Case ......................................................................65
5.4 Unit Price of Transport Cost .........................................................................................69
5.5 Results and Data Synthesis ...........................................................................................70
5.6 Discussion .....................................................................................................................74
5.7 Summary .......................................................................................................................75
Chapter 6: Evaluating a Toll Tunnel Project .................................................. 77
6.1 Examining Perspectives ................................................................................................77 6.1.1 Hypothesis ..........................................................................................................77 6.1.2 Consideration of Cost Formats of Toll Road Projects ........................................78 6.1.3 Perspectives Considered for this Study ..............................................................81
6.2 Methodology .................................................................................................................82
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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6.2.1 Identifying Concession Payments and Costs ..................................................... 83 6.2.2 Estimation of Benefit ......................................................................................... 83 6.2.3 Evaluation and Decision Making ....................................................................... 84
6.3 Model Development ..................................................................................................... 84 6.3.1 Traffic Volume and Growth .............................................................................. 84 6.3.2 Baseline Toll Price ............................................................................................. 84 6.3.3 Minimum Revenue Guarantee ........................................................................... 86 6.3.4 Premium Toll ..................................................................................................... 87
6.4 Results .......................................................................................................................... 88 6.4.1 Evaluation and Decision making of the Synthesised Toll Tunnel Project
Case .................................................................................................................... 88 6.4.2 Examination of Perspectives .............................................................................. 91 6.4.3 Sensitivity Analysis of Variation in Risk Characteristics .................................. 92
6.5 Discussion .................................................................................................................... 98
6.6 Summary ...................................................................................................................... 99
Chapter 7: Evaluating a Toll Road Project ................................................... 103
7.1 Synthesising a Toll Road Project Case ...................................................................... 103
7.2 Synthesised Toll Road Project Case Characteristics .................................................. 105
7.3 Results ........................................................................................................................ 106 7.3.1 Evaluation and Decision making of the Synthesised Toll Road Project
Case .................................................................................................................. 106 7.3.2 Sensitivity Analysis of Variation in Risk Characteristics ................................ 110
7.4 Comparison between Toll Tunnel and Road Projects ................................................ 116 7.4.1 A Review of Benefit-Cost Ratio ...................................................................... 116 7.4.2 A Review of Risk Profiles and Perspectives.................................................... 117
7.5 Summary .................................................................................................................... 117
Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects 119
8.1 Typical Project Appraisal Process ............................................................................. 119
8.2 Framework of the Proposed Methodology ................................................................. 120
8.3 Practical Considerations ............................................................................................. 122 8.3.1 Conducting the Analysis .................................................................................. 122 8.3.2 Interpreting the Results .................................................................................... 123
8.4 Enhancement and Refinement of the Proposed Methodology ................................... 126
8.5 Suggested Future Studies ........................................................................................... 126
8.6 Summary .................................................................................................................... 127
Chapter 9: Conclusion ..................................................................................... 129
9.1 Summary of Findings ................................................................................................. 129 9.1.1 Literature Review ............................................................................................ 129 9.1.2 A Review of Australian Practice of Cost-Benefit Analysis ............................. 129 9.1.3 Incorporating Stochastic Approach in Cost-Benefit Analysis ......................... 130 9.1.4 Evaluating a Toll Tunnel Project ..................................................................... 130 9.1.5 Evaluating a Toll Road Project ........................................................................ 131 9.1.6 Proposed Methodology .................................................................................... 131
9.2 Review of the Research Questions ............................................................................. 132 9.2.1 Research Question 1 ........................................................................................ 132
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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9.2.2 Research Question 2 .........................................................................................133 9.2.3 Research Question 3 .........................................................................................133 9.2.4 Research Question 4 .........................................................................................133
9.3 Contribution to Theory ...............................................................................................134
9.4 Contribution to Practice ..............................................................................................135
9.5 Recommendations for Future Work ...........................................................................137
9.6 Concluding Remarks ..................................................................................................138
List of Publications and Awards ........................................................................... 139
References ............................................................................................................... 141
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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List of Figures
Figure 2.1 Study methodology flowchart ................................................................... 12
Figure 2.2 Detailed links between outputs of each phase .......................................... 16
Figure 5.1 Box-and-whisker plots of Benefit-Cost Ratio (BCR) with each
variable varied stochastically, and all variables varied stochastically ......... 73
Figure 6.1 Payment movement of when toll roads are delivered and operated
by the host government from the “toll as a transfer payment” (TT)
perspective ................................................................................................... 79
Figure 6.2 Payment movement of when toll roads are delivered and operated
privately from the “toll as an end-user cost” (TC) perspective .................... 80
Figure 6.3 Payment movement of when the private operator charges premium
tolls from the TC perspective ....................................................................... 81
Figure 6.4 Methodology of the evaluation of the synthesised toll tunnel project
case ............................................................................................................... 83
Figure 6.5 Cumulative stochastic Benefit-Cost Ratio (BCR) distributions of the
synthesised toll tunnel project case .............................................................. 90
Figure 6.6 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll tunnel project case .............................................................. 91
Figure 6.7 Cumulative stochastic Benefit-Cost Ratio (BCR) distributions of the
synthesised toll tunnel project case when the annual average daily
traffic (AADT) and the traffic growth rate variables are treated as
stochastic ...................................................................................................... 94
Figure 6.8 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll tunnel project case when the AADT and the traffic
growth rate variables are treated as stochastic ............................................. 95
Figure 6.9 Cumulative stochastic BCR distributions of the synthesised toll
tunnel project case when capital cost variable is treated as stochastic ........ 95
Figure 6.10 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll tunnel project case when capital cost variable is
treated as stochastic ...................................................................................... 96
Figure 6.11 Cumulative stochastic BCR distributions of the synthesised toll
tunnel project case when vehicle hours travelled saving (VHTS)
variable is treated as stochastic .................................................................... 97
Figure 6.12 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll tunnel project case when VHTS variable is treated as
stochastic ...................................................................................................... 98
Figure 1.1 Cumulative stochastic Benefit-Cost Ratio (BCR) distributions of the
synthesised toll road project case ............................................................... 109
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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Figure 1.2 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll road project case ............................................................... 110
Figure 1.3 Cumulative stochastic BCR distributions of the synthesised toll road
project case when the annual average daily traffic (AADT) and the
traffic growth rate variables are treated as stochastic ................................ 112
Figure 1.4 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll road project case when the AADT and the traffic
growth rate variables are treated as stochastic ........................................... 113
Figure 1.5 Cumulative stochastic BCR distributions of the synthesised toll road
project case when the capital cost variable is treated as stochastic ........... 114
Figure 1.6 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll road project case when the capital cost variable is
treated as stochastic.................................................................................... 114
Figure 1.7 Cumulative stochastic BCR distributions of the synthesised toll road
project case when the vehicle hours travelled saving (VHTS) variable
is treated as stochastic ................................................................................ 115
Figure 1.8 Box-and-whisker plots of stochastic BCR distributions of the
synthesised toll road project case when the VHTS variable is treated
as stochastic ............................................................................................... 116
Figure 8.1 Project appraisal process......................................................................... 120
Figure 8.2 The proposed Cost-Benefit Analysis (CBA) framework for major
road projects ............................................................................................... 121
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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List of Tables
Table 2.1 Measures of risk profiles and their interpretations .................................... 15
Table 3.1 Evaluation of toll road projects found in academic literature ................... 19
Table 3.2 Use of the Monte Carlo simulation in assessment of transport
projects ......................................................................................................... 33
Table 4.1 Project proponent of the study cases ......................................................... 41
Table 4.2 Toll road operators and owners of the study cases ................................... 42
Table 4.3 Economic parameters used in the study cases ........................................... 43
Table 4.4 Travel time unit price per hour in 2015 dollars ......................................... 45
Table 4.5 Vehicle operating cost saving unit price per km in 2015 dollars .............. 46
Table 4.6 Crash cost saving unit price in 2015 dollars .............................................. 47
Table 4.7 Environmental and external cost types ...................................................... 48
Table 4.8 Environmental and external cost saving (EECS) unit price per km in
2015 dollars .................................................................................................. 49
Table 4.9 Assumed lifespan of the study cases .......................................................... 50
Table 4.10 Sensitivity analysis conducted in the study cases .................................... 52
Table 4.11 Recommended sensitivity analysis in the Australian guidelines ............. 53
Table 5.1 Probability distribution forms and coefficient of variable (CV) of the
case depend input variables .......................................................................... 64
Table 5.2 Probability distribution forms and coefficient of variable (CV) of
transport cost unit prices .............................................................................. 65
Table 5.3 Characteristics of Brisbane toll tunnels ...................................................... 67
Table 5.4 Assumptions made in Cost-Benefit Analysis (CBA) calculation of
the synthesised toll tunnel project case ........................................................ 68
Table 5.5 Transport cost unit price summary ............................................................. 70
Table 5.6 Impacts of the synthesised toll tunnel case when all variables were
deterministically equal to their expected values in present value ................ 71
Table 5.7 Risk profiles of output Benefit-Cost Ratio (BCR) distribution as
input variable was distributed stochastically ............................................... 72
Table 6.1 Costs to the community that are considered in Cost-Benefit Analysis
(CBA) for this study ..................................................................................... 82
Table 6.2 Risk profiles of the synthesised toll tunnel project case across
perspectives and scenarios ........................................................................... 89
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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Table 6.3 Risk profiles of the synthesised toll tunnel project case across
perspectives and scenarios when each variable was treated as
stochastic ...................................................................................................... 93
Table 7.1 Characteristics of Australian toll roads .................................................... 104
Table 1.2 Project costs of West Petrie Bypass project in 2015 dollars (GHD,
2013) .......................................................................................................... 105
Table 1.3 Assumptions made in Cost-Benefit Analysis (CBA) calculation of
the synthesised toll road project case ......................................................... 106
Table 1.4 Impacts of the synthesised toll road project case when all variables
were deterministically equal to their expected values in present value ..... 107
Table 1.5 Risk profiles of the synthesised toll road project case across
scenarios ..................................................................................................... 108
Table 1.6 Risk profiles of the synthesised toll road project case across
scenarios when each variable was treated as stochastic ............................. 111
Table 8.1 Interpretations of the risk profiles in the proposed methodology ............ 124
Table 8.2 Interpretations of cumulative probability distribution graphs, and
box-and-whisker plots in the proposed methodology ................................ 125
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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List of Abbreviations
Abbreviation Definition
APL Airport Link
AADT Annual average daily traffic
BCR Benefit-Cost Ratio
BNG Baseline toll, no guarantee
BRG Baseline toll, minimum revenue guarantee
BOT Build-operate-transfer
CBD Central business district
CYL City Link
CV Coefficient of variation
CBA Cost-Benefit Analysis
CC Crash cost
CCS Crash cost saving
DBFO Design-build-finance-operate
EEC Environmental and external cost
EECS Environmental and external cost saving
GUP Gateway Upgrade Project
GHG Greenhouse gas emission
HSB Horsham Bypass
HV Heavy vehicles
HV% Proportion of heavy vehicles
LGW Legacy Way
LV Light vehicles
MCDA Multi-Criteria Decision Analysis
NSW New South Wales
O&M Operation and maintenance
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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Abbreviation Definition
PNG Premium toll, minimum revenue guarantee
PPP Public-Private Partnership
RMS Roads and Maritime Services
RV Residual value
SNB Singleton Bypass
TC Toll as an end-user cost
TT Toll as a transfer payment
TWB Toowoomba Bypass
VFM Value for money
VHTS Vehicle hours travelled saving
VKTS Vehicle kilometres travelled saving
VOC Vehicle operating cost
VOCS Vehicle operating cost saving
WEB Wider Economic Benefits
WPB West Petrie Bypass
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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Principal Notation
Symbol Definition Unit
𝐴𝐴𝐷𝑇𝑖,𝑗 Initial average annual daily traffic for Monte Carlo trial 𝑗 veh
𝐴𝐴𝐷𝑇𝑗,𝑦 Average annual daily traffic at year 𝑦 for trial 𝑗 veh/d
𝐴𝐴𝐷𝑇𝑦,𝑒𝑥𝑝 Expected AADT with expected traffic growth at year 𝑦 veh
𝐵𝑗,𝑦 Total annual project benefit at year 𝑦 for trial 𝑗 $
𝐶𝑎𝑝 Total capital cost over the whole planning horizon in present value $
𝐶𝑎𝑝𝑎𝑣 Expected capital cost $
𝐶𝑎𝑝𝑗 Capital cost in present value for trial 𝑗 $
𝐶𝑎𝑝𝑚𝑖𝑛 Minimum feasible capital cost $
𝐶𝐶𝑗 Crash cost unit price for trial 𝑗 $/veh-
km
𝑑 Discount rate applicable to the project format %
𝐸𝐸𝐶𝑗,𝑘 Environmental and external cost unit price for the vehicle type 𝑘 for
trial 𝑗
$/veh-
km
𝑔𝑗 Traffic growth rate for Monte Carlo trial 𝑗 %
𝐺𝑦,𝑒𝑥𝑝 Expected guarantee payment at year 𝑦 in present value $
𝑖 Annual rate of inflation in the economy %
𝑘 Vehicle type, 𝑘 ∈ (𝐿𝑉,𝐻𝑉) na
𝑙 Number of Monte Carlo trials na
𝑛 Period of planning horizon years
𝑂&𝑀 Total operation and maintenance cost over the whole planning
horizon in present value
$
𝑂&𝑀𝑗 Total O&M cost over the whole planning horizon for trial 𝑗 $
𝑃(𝑘)𝑗 Proportion of vehicle type 𝑘 for trial 𝑗 %
𝑟 Financier’s interest rate on the private entity’s loan %
𝑅𝑉 Residual value of the road $
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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Symbol Definition Unit
𝑅𝑉𝑗 Residual value of the road for trial 𝑗 $
𝑇𝑃𝑏𝑎𝑠𝑒,𝑗 Baseline toll price for Monte Carlo trial 𝑗 $
𝑇𝑇𝑗,𝑘 Travel time unit price for the vehicle type 𝑘 for trial 𝑗 $/veh-h
𝑈𝑃 Upfront payment to capital cost $
𝑉𝐻𝑇𝑆𝑗 Vehicle hours travelled saved by using the road for trial 𝑗 h
𝑉𝐾𝑇𝑆𝑗 Vehicle kilometre travelled saved by using the road for trial 𝑗 km
𝑉𝑂𝐶𝑗,𝑘 Vehicle operating cost unit price for the vehicle type 𝑘 for trial 𝑗 $/veh-
km
𝑦 Corresponding year, 𝑦(0, 1,… , 𝑛) na
𝜙 Probability that capital cost exceeds 𝐶𝑎𝑝𝑚𝑖𝑛 %
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
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Statement of Original Authorship
The work contained in this thesis has not been previously submitted to meet
requirements for an award at this or any other higher education institution. To the best
of my knowledge and belief, the thesis contains no material previously published or
written by another person except where due reference is made.
QUT Verified Signature
Developing a Methodology for Evaluating Privately Operated Toll Road Projects Using Stochastic Cost-Benefit
Analysis
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Acknowledgements
I would like to express my deepest gratitude to my principal supervisor, Associate
Professor Dr Jonathan Bunker, for his support throughout my PhD study. He has
demonstrated incredible capability as a researcher, a PhD supervisor, a unit
coordinator, and a mentor in the course of my study. His guidance and encouragement
have led me to the early completion of my PhD.
I would like to thank my associate supervisors, Professor Stephen Kajewski and
Dr Melissa Teo for their support.
I would also like to acknowledge the professional editing service that Diane
Kolomeitz has provided for this thesis, in accordance with the Australian Guidelines
for Editing Research Theses.
Finally, I would like to thank my husband, Kuan-Yu Wesley Chi, and my son,
Nathan Chun-Hsiang Akihiro Chi, for their continuous support and understanding.
Chapter 1: Introduction 1
Chapter 1: Introduction
This chapter explains the research motivation and the purpose of this study. The
research aim, hypothesis and research objectives are stated. The methodology of this
study is explained in detail. The scope and significance of this study are then discussed.
The thesis outline is presented in the final section.
1.1 BACKGROUND
Cost-Benefit Analysis (CBA) is conducted for major road projects for the purpose of
evaluations. CBA measures and quantifies project impacts. The decision making using
CBA is mainly based on the Benefit-Cost Ratio (BCR), which is a ratio of benefits to
costs of the project.
Traditionally, tolls are considered as financial transfers between the road users
and the host government in the CBA of a toll road project. However, when the toll
road project is delivered through a form of Public-Private Partnership (PPP) scheme
and the tolls are collected by the private operator, it is questionable whether to treat
the tolls as financial transfers.
Also important is the complex risk arrangement of many toll road projects that
need to be properly assessed in project evaluation. Many recent toll roads, such as
Legacy Way and Clem Jones Tunnel, both in Brisbane, Australia, are delivered
through forms of PPP scheme. This allows the host government to shift a part of project
risks, including the traffic and revenue risks to the private operator. A commonly
known risk-sharing strategy of a toll road project is the minimum revenue or traffic
guarantee. Depending on the project, a number of risk-sharing strategies can be used
to control the proportion of risks that are shifted to the private operator. Quantifying
and measuring risks that are borne by the host government is crucial in the decision
making of a large infrastructure project, such as a toll road, in terms of the public good.
The complex risk-sharing arrangement that can be unique to each toll road project
needs to be properly quantified and assessed. In other words, the shifts of risk need to
be displayed and communicated in the project evaluation outcomes.
For the host government to ensure that the benefits of a decision outweigh its
costs, addressing net impacts and risks to the community are crucial in project
2 Chapter 1: Introduction
evaluation. The representation of the net risk in CBA is limited by point assumptions
using one-way sensitivity analysis.
A number of studies exist with respect to traffic and revenue forecast accuracies
(Bain, 2009; Carpintero, 2010; Li & Hensher, 2010), financial risks (Aldrete, Bujanda,
& Valdez, 2012; Mishra, Khasnabis, & Swain, 2013), toll pricing (Anas & Lindsey,
2011; Welde, 2011; Zhang, 2008) and concession arrangements (Vassallo, Ortega, &
Baeza, 2012) of toll road projects. However, past studies express limited knowledge
with respect to the appropriate treatment of tolls in the CBA for a privately operated
toll road project and measuring risks using CBA.
1.2 AIM OF THIS STUDY
The aim of this study is to examine the impacts and the risks of a toll road project to
the community, in order to reflect them in Cost-Benefit Analysis (CBA). This study
has a particular focus on altering treatments of some of the project impacts of a toll
road project and reflecting them in CBA outcomes. The payment movements between
different entities, such as road users, non-road users, the host government and the toll
operator are considered, in order to explore an appropriate treatment of tolls in CBA.
Examining various payment movements and altering treatments of impacts
accordingly within CBA have not been studied in literature. This study also explores
how risks can be represented in CBA by incorporating a stochastic approach using the
Monte Carlo simulation. This is particularly useful to quantify risks of the projects
with various risk characteristics using various forms of Public-Private Partnership
scheme. The purpose of this study is to propose a methodology that can readily be used
in practice. Therefore, the study outcomes contribute directly to CBA practitioners and
professionals in transport economics. The hypothesis that is to be tested in this study
is the following.
“The estimation of net impacts and risks of a toll road project to the
community for the purpose of project evaluation can be improved by
considering the treatment of project impacts and performing stochastic Cost-
Benefit Analysis.”
To test this hypothesis, the following research questions have been drawn.
1. How have various toll road projects been evaluated using CBA in practice?
Chapter 1: Introduction 3
2. Does the extant CBA methodology that is used to evaluate toll road projects
properly reflect the net impacts and risks to the community of a toll road?
3. Can CBA results properly reflect the source/s of risks of a toll road project
by incorporating a stochastic approach?
4. How does altering treatments of some impacts of a toll road project in CBA
improve its outcomes in terms of reflecting net impacts and risks to the
community?
The literature review highlighted:
• the limited studies conducted regarding the CBA for the purpose of evaluation
of toll road projects
• the representation of risks in CBA requires improvements with empirical
assessments and representations of risks; and
• a scarcity of investigating the treatment of tolls in CBA.
The research questions are designed to fill these research gaps. The following research
objectives of this study have been developed to answer the above stated questions.
1. Review the extent CBA methodology by studying the current guidelines,
academic studies and previously conducted CBA for the purpose of
evaluation of toll road projects to highlight any limitations and difficulties
of CBA (in response to the first and the second research questions)
2. Examine the outcomes of the stochastic CBA to observe how the source/s
of risks are reflected in the outcomes (in response to the third research
question)
3. Synthesise a project on the basis of existing toll road projects, in order to
determine the methodology that best reflects the net impacts and risks of a
toll road project to the community (in response to the third research
question)
4. Investigate the outcomes of CBA of a toll road project when the treatment
of project impacts varies by examining various payment movements (in
response to the fourth research question)
4 Chapter 1: Introduction
1.3 SCOPE AND DEFINITIONS
The scope of this study includes project evaluation for public and private major road
projects. Evaluations of other infrastructure types are beyond the scope of this study.
This study uses Cost-Benefit Analysis (CBA) as a project evaluation methodology and
the impacts considered in the study are limited to the ones that can be addressed in
CBA. Evaluations with respect to the financial viability and other non-monetised
impacts that are not addressed in CBA are beyond the scope of this study.
A risk is defined as any uncertain event associated with the work (Kendrick,
2009). This study considers “risks” as measurable factors that may or may not
influence the project. Considering “uncertainties” is beyond of the scope of this study
as these are defined as unmeasurable factors (Knight, 2012).
The scope of the case study conducted as part of this study reviews toll and non-
toll road projects in various states of Australia and UK. The finding of the case study
is not limited to a specific state, however is limited to Australian and UK contexts and
the contexts of the countries with a similar settings. In Australia and UK, transport
projects that are costly, such as tunnel projects, tend to be tolled. Particularly in
Brisbane, Australia, there have been several toll tunnels built in a short time frame.
The purpose of the case study is to examine how CBA is conducted in practice, instead
of identifying the appropriate methodology for a toll road project, which is instead
considered in Chapter 5. Ten study cases are examined and the findings of the case
study indicate general practice of CBA for Australian major road projects. A review
of CBA for the purpose of financial or accounting audits is beyond the scope of this
study.
This study implements the most common CBA methodology for a major road
project and does not address a range of different CBA methodologies. The theory of
CBA is discussed in Chapter 3. The toll road and tunnel project cases are synthesised
on the basis of overarching characteristics of a selection of recent toll road projects in
Australia. Therefore, the characteristics of the synthesised cases represent realistic toll
road project characteristics. The findings of this study do not consider projects with
unordinary characteristics. Notwithstanding, the findings of this study are applicable
to many toll road projects, including both publicly and privately operated roads. The
synthesised cases are not geographically specific, and therefore the findings of this
study are not limited to a specific city or state.
Chapter 1: Introduction 5
The stochastic representations of risks of a project rely heavily on the probability
distributions used in the Monte Carlo simulation. A range of literature is reviewed, in
order to determine the appropriate probability distribution for each input variable.
However, studies of the probability distributions of annual average daily traffic
(AADT), forecasted traffic growth rate, the proportion of heavy vehicles (HV%),
vehicle kilometres travelled saving (VKTS), and the unit price of environmental and
external cost saving (EECS) have not been addressed in literature. Further statistical
studies are required to determine the appropriate probability distributions of these
variables.
There may be possible methodological limitations, such as limitations with data
analysed and synthesised, and uncertainties with the results of analyses. After
completing the interpretation of the findings, there may be important issues that need
to be analysed but were not included in the analysis. The processes of data analysis
and synthesis can be repeated as necessary so that the important issues can be analysed
through the processes.
1.4 STUDY CONTRIBUTIONS AND THEIR SIGNIFICANCE
The outcomes of this study are listed in Figure 2.1. The key outcome of this study is
the treatments of impacts of toll road projects in CBA that better reflect the net impacts
and risks to the community. This study also proposes the methodology that best reflects
the net impacts and risks of both publicly and privately operated toll road projects to
the community and can readily be used in practice. Moreover, incorporating well-
established methodologies, such as CBA and the Monte Carlo simulation ensures the
reliability of the proposed methodology.
Addressing net impacts and risks to the community in project evaluation are
crucial in decision making by the host government of a large infrastructure project that
is intended for public use. The host government needs to ensure that the benefits of the
decision outweigh its costs. This study will propose the methodology that provides the
host government with a toll to evaluate major PPP projects from the public perspective.
This methodology can be useful to evaluate the project to assess whether the project is
beneficial to the community, instead of solely focussing on its financial viability. This
particularly significant in extant academic study by providing extended knowledge
regarding CBA for the purpose of evaluating toll road projects.
6 Chapter 1: Introduction
This study has a particular focus on toll tunnel projects. The unique
characteristics of a toll tunnel project that would impact the CBA are the fact that it’s
tolled and its substantial capital costs. Compared to a non-tolled major road project,
economic impacts of a toll road project to the community would be different, because
the road users are responsible in paying to use the road. This difference should be
reflected in its CBA outcomes. Additionally, the economic justification of a toll tunnel
project, which have considerable capital costs is crucial. Therefore, conducting CBA
appropriately for a toll tunnel project to reflect the net impact and risk to the
community is essential in the decision making about a public good.
This study investigates the treatment of tolls in CBA by considering different
perspectives. Previous studies provide limited knowledge regarding the treatment of
tolls. Additionally, consideration of perspectives in CBA has not been studied. The
knowledge that can be obtained from this study can be extremely significant in both
academic studies and CBA practices.
Presenting the evaluation outcomes in an empirical manner allows them to be
communicated effectively in the decision making process. The representation of risks
using the extant CBA-based project evaluation methodology of a toll road project is
limited by point assumptions made when using one-way sensitivity analysis. This
study uses the stochastic CBA by incorporating the Monte Carlo simulation approach,
in order to present the risks in an effective manner. The risks can be represented in an
empirical manner by incorporating the Monte Carlo simulation in the CBA, and
therefore a comprehensive risk profile can be developed for a project. The attempt to
incorporate the Monte Carlo simulation in the CBA of a road project was found to
have been first conducted by Salling and Leleur (2011). In contrast to that study, this
study considers wider variety of risks of all input variables and also attempts to model
the level of each risk by applying variety of probability distributions to each variable.
On the basis of the stochastic representations of risks, various concession payments
that are often included in the concession arrangement of a privately operated toll road
project are further investigated in this study. This leads to appropriate reflection of the
shifts of risk between the public and private sectors in the CBA.
Moreover, reflecting payment movements in financial analysis of privately
operated toll road projects has been studied in Mishra et al. (2013), however it has not
been studied particularly for CBA of a major road project. Considering the payment
Chapter 1: Introduction 7
movements between road users, non-road users, the host government and the toll
operator of a privately operated toll road project may alter the treatment of some
project impacts in CBA and therefore may alter the outcome of the analysis.
Through the stochastic CBA, the effectiveness of various statistical inferences
to evaluate toll road projects can be investigated. Using various measures, different
PPP scenarios and delivery options can be explored. This can be particularly useful in
practice.
1.5 THESIS OUTLINE
An outline of this thesis is shown in the following.
Chapter 1 details the background, purpose, scope and definitions, and
significance of this study. The research aim, research hypothesis, research questions
and research objectives of this study are stated. Scope, definitions and limitations of
this study are addressed. The importance, key outcomes and the evidence of
significance of this study are then discussed.
Chapter 2 proposes the research methodology of this study. It discusses
methodologies and methods that are used in this study, and linkages to previous
studies. An illustrative presentation of the methodology is also shown. Each phase of
this study is then explained in detail.
Chapter 3 presents the literature review that is conducted for this study in
response to the first research objective. This review first revisits the purpose of project
evaluation and the role of the governments in decision making of major road projects.
On the basis of the purpose of project evaluation, it highlights the limitations of
evaluations conducted recently. The fundamental underpinning of Cost-Benefit
Analysis (CBA) is then summarised and distinctions between CBA and financial
analysis are outlined. The risks that are specific to toll road projects, including traffic
forecasts and toll prices that can significantly impact the outcome of their evaluations
are considered to determine their implications in project evaluation. Incorporating the
Monte Carlo simulation approach in the CBA was recently proposed in Salling and
Leleur (2011, 2017). To extend this knowledge, the chapter reviews the use of the
Monte Carlo simulation to assess transport infrastructure projects in recent literature.
A summary of this review and discussions with regard to gaps that need to be addressed
in future study are presented in the final section.
8 Chapter 1: Introduction
Chapter 4 discusses the review of CBA of Australian and UK major road projects
in response to the first research objective. Ten study cases, including four non-tolled
roads and six toll roads, are reviewed. A brief background to each study case is
provided. The input variables of the cases, such as planning, horizon, discount rate and
costs are presented. Then, the calculations of benefits are reviewed, including various
unit prices used to monetise impacts. Residual value (RV) calculations and the
variables that are tested in sensitivity analysis are reviewed. The treatment of tolls,
practical issues and further considerations of input variables are discussed.
Chapter 5 explores the influence of risks of each input variable in response to
the second and third research objectives. CBA theory is first reviewed, then the
appropriate probability distributions for capital cost, case dependent variables and
transport unit prices are explored. A toll tunnel project case is then synthesised on the
basis of the overarching characteristics of a selection of toll tunnel projects in Brisbane,
Australia. The synthesised case is then evaluated using the CBA. The risk profile of
the synthesised case is then developed using the stochastic Benefit-Cost Ratio
distribution that is produced using the Monte Carlo simulation. Results and discussions
are then summarised.
Chapter 6 examines payment movements and evaluates the previously
synthesised toll tunnel project case in response to the fourth research objective. The
payment movements are first examined by considering a number of concession
payments that are often used to share the risks, and a number of scenarios, including
when the project is publicly operated and privately operated. On the basis of the
examination, the models for the concession payments are developed. The synthesised
case is then evaluated using the same approach as the one used in Chapter 5. The
outcome BCR distribution is then reviewed to determine how the risk is reflected in
the risk profile. The results and discussions are then summarised.
Chapter 7 explores the CBA of a toll road project using the previously proposed
methodology in response to the fourth research objective. A toll road project case is
synthesised on the basis of the overarching characteristics of a selection of toll road
projects in Australia. The synthesised case is then evaluated using the same approach
as the one used in Chapter 5 and Chapter 6. The risk profiles of both tunnel and road
projects are then compared. The results and discussions are then summarised.
Chapter 1: Introduction 9
Chapter 8 details the proposed methodology. It reviews the existing Australian
project appraisal process to determine how the proposed methodology can be
incorporated within the existing framework. It also details the framework of the
proposed methodology to show how each step can be incorporated in a typical CBA
framework. Practical considerations and future studies are discussed in the final
sections.
Chapter 9 presents overall conclusion, limitations and recommendations of this
study. The contributions both to the academic study and practice are discussed. Future
study and discussions of where this study may be extended are also discussed in the
final section.
1.6 SUMMARY
This chapter provided background and the aim of this study. The hypothesis that is
tested in this study is stated and research questions were drawn on this basis. Research
objectives were developed to answer those questions. It then discussed the
methodology, scope and significance of this study. An outline of this thesis was
provided in the final section.
Chapter 2: Research Methodology 11
Chapter 2: Research Methodology
This chapter describes the research methodology of the study. The research
methodology is designed to test the previously stated hypothesis and to achieve the
previously stated research objectives. This study revolves around Cost-Benefit
Analysis (CBA) as the most commonly used project evaluation methodology for major
road projects. CBA is a well-established project evaluation methodology that is
commonly used in practice. Sinha and Labi (2007) specify the fundamental
underpinning of the CBA in great detail.
2.1 METHODOLOGY FRAMEWORK
Figure 2.1 depicts this study. The corresponding research objectives are shown in
brackets. The knowledge that can be gained through the literature review and the case
study are shown in dashed boxes, which are incorporated throughout this study. The
key research outputs are shown in thick lined boxes. Each phase is discussed in detail
in the following sections.
12 Chapter 2: Research Methodology
Figure 2.1 Study methodology flowchart
2.2 LITERATURE REVIEW
A range of recent literature is reviewed. These include recent academic literature and
publications of Australian transport authorities, such as Austroads, and Australian
Transport and Infrastructure Council, to review the project evaluation methodologies
that are often used in practice. The aim of this review is to outline the potential barriers
in evaluating toll road projects to address net impacts and risks. This review does not
contain reviews of previously conducted evaluations. Rather, it suggests potential
barriers in the evaluation of toll road projects on the basis of theories and findings of
recent studies, and advice of transport authorities.
Chapter 2: Research Methodology 13
2.3 COMPARATIVE CASE STUDY
The comparative case study investigates how major road projects, including toll road
projects in Australia, have been evaluated using CBA in practice, and compares the
analyses of toll road projects with those of non-tolled road projects. The aim of this
case study is to identify the limitations and difficulties in existing practices of CBA.
The calculations of project capital cost, user benefits and residual value (RV), the
treatment of tolls, and methodology of sensitivity analysis are reviewed. Reviewing
and examining CBA cases can highlight the limitations in existing practices of CBA
for major road projects, as well as the most significant factors in the outcomes of the
evaluation. This will allow the complexity of CBA for major road projects in practice
to be explored.
2.4 INCORPORATING STOCHASTIC APPROACH IN COST-BENEFIT
ANALYSIS
The aim of this phase is to develop a stochastic CBA framework. The parameters that
contain some level of risks, such as those that are estimated using some modelling
technique or monetised using market value estimations, are examined using the Monte
Carlo simulation, which is incorporated within the framework. These variables include
capital cost, annual average daily traffic (AADT), traffic growth, proportion of heavy
vehicles (HV%), vehicle kilometres travelled saving (VKTS), vehicle hours travelled
saving (VHTS) and various transport costs. For each variable, the form of probability
distribution, mean, and coefficient of variation (CV) are defined based on the project
characteristics of the synthesised case and inference from a range of literature.
Deterministic values of planning horizon and discount rate are incorporated in this
study. Operation and maintenance (O&M) cost was assumed to be ten percent of the
whole capital cost. The percentage was determined based on the CBA case study
conducted (see Section 4.3). Hence, O&M cost is stochastic when capital cost is
stochastic.
The Monte Carlo simulation is a well-established risk analysis tool. Mun (2010)
explains the fundamental underpinning of the Monte Carlo simulation methodology in
great detail. The Monte Carlo simulation can be used to produce a stochastic Benefit-
Cost Ratio (BCR) set on the basis of a sufficiently large number of trials, and hence a
comprehensive risk profile of the project on the basis of various combinations of input
impacts. In this study, with each trial, the value of each variable was simulated by a
14 Chapter 2: Research Methodology
Monte Carlo draw from its predefined probability distribution with predefined mean
and coefficient of variation (CV). When 100,000 trials are conducted, a set of 100,000
BCR values will be obtained to ensure a sufficiently representative variation in output.
This set represents the outcome stochastic BCR distribution for the project of interest.
2.5 SYNTHESISING TOLL ROAD AND TUNNEL PROJECT CASES
This study first considers a toll tunnel project instead of a toll road project due to the
considerable scale of its construction cost. They key difference between a toll road
project and a toll tunnel project is the scale of the project. The lengths of a toll road
and a toll tunnel can vary significantly and this may change their VHTS and VKTS.
Economic justification of a tunnel project is therefore particularly crucial in project
evaluation. A toll tunnel project case and a toll road project case were synthesised to
demonstrate a stochastic approach to project evaluation on the basis of overarching
characteristics of existing toll road projects. This study seeks useful insights through
investigations of both tunnel and road projects. The purpose of studying the
synthesised cases was so that their project characteristics could be adjusted in a
controlled manner to examine various risk scenarios.
2.6 PROFILING RISK USING BENEFIT-COST RATIO DISTRIBUTION
DRAWN FROM SIMULATION
The BCR distribution that was generated using CBA and the Monte Carlo simulation
can be analysed using various statistical inferences. The interpretations of various
measurements provide a comprehensive representation of the risk of a project. Table
2.1 shows the statistical inferences that were used in this study, which are particularly
useful for comparisons of different scenarios or methodologies. For instance, CV of
the outcome BCR distribution can be compared with the predefined CVs of input
variables to assess how the risk of each input variable impacts the risk of the outcome
BCR.
Chapter 2: Research Methodology 15
Table 2.1 Measures of risk profiles and their interpretations
Risk
profile Measures used in this study Interpretation
Central
tendency
Mean, reflecting the
expected Benefit-Cost Ratio
(BCR)
A higher value reflects a lower risk profile.
Median, reflecting the
middle BCR
A higher median than mean reflects a lower
risk profile.
Spread Coefficient of variation (CV) CV is a normalised measure of spread. A
higher CV implies a wider distribution, for a
higher risk profile.
Skew Skew Positive skew corresponds to a longer right
hand tail of the BCR, for a lower risk profile.
Percentile
The probability of a specific
BCR
The proportion of BCR trials greater than 1.0
represents the probability of the project being
beneficial. A higher probability reflects a lower
risk profile.
2.7 ALTERING PROJECT IMPACTS IN THE COST-BENEFIT ANALYSIS
Two perspectives of “toll as a transfer payment” and “toll as an end-user cost” are
drawn from the findings of literature review and comparative case study. On the basis
of these perspectives, the treatment of tolls and other payments that are often used in
toll road projects are examined. These payments are examined by observing their
movements between various entities, such as road users, non-road users, the host
government and the private operator. Models of each payment are then developed to
reflect these movements. The synthesised cases are evaluated using the stochastic CBA
and the developed models. Examination of the risk profiles of different payment
scenarios reveals how shifts of risk can be portrayed in the stochastic CBA. This also
determines the treatment of project impacts that best reflects the risk characteristics of
a toll road project across scenarios.
16 Chapter 2: Research Methodology
2.8 PROPOSED METHODOLOGY FOR EVALUATIONS OF TOLL ROAD
PROJECTS
The key contribution of this study is the proposed CBA methodology that best reflects
the net impacts and risks to the community. Figure 2.2 illustrates the links between
outputs of each phase of this study, for the purpose of developing the methodology.
The stochastic CBA methodology is developed, and project characteristics are
determined in Chapter 5. Using the methodology developed, and the characteristics,
the synthesised project is evaluated. Its risk profile and the impacts of altering
treatments of project impacts on the risk profile are studied. The appropriate treatments
to best reflect the net impacts and risks to the community can then be determined. The
appropriate treatments are incorporated into the stochastic CBA, in order to propose
the methodology in Chapter 8.
Figure 2.2 Detailed links between outputs of each phase
Chapter 3: Literature Review 17
Chapter 3: Literature Review
Evaluating and making decisions about large-scale investment is a complex and
difficult task. Toll road projects are often large-scale projects. Large-scale investment
can receive significant public scrutiny. An empirical and comprehensive project
evaluation tool is crucial in decision making to ensure that the benefits of the decision
outweigh the costs and risks that the governments and the communities are bearing.
Toll road projects are often delivered through a form of Public-Private
Partnership (PPP) scheme, in part to shift a part of risks to the private operator. These
shifts of risk need to be considered in project evaluation to assess the risks that the
public is bearing. These toll road specific characteristics require that the methodology
is adapted specifically to toll road projects. Using traditional project evaluation
methodology, the risk characteristics that are unique to many toll road projects may be
miscalculated or ignored.
The aim of this review is to outline the potential barriers in evaluating toll road
projects to address net impacts and risks. This chapter reviews academic literature and
publications of Australian road authorities, such as Austroads, and the Australian
Transport and Infrastructure Council, to review the project evaluation methodologies
that are often used in practice. This review does not contain reviews of previously
conducted evaluations. Rather, it suggests potential barriers in evaluation of toll road
projects on the basis of theories and findings of recent studies and guidelines.
3.1 PROJECT EVALUATION FOR PUBLIC GOOD
Governments are responsible for decision making for the good of their constituents.
This includes ensuring that public funds are invested wisely, and that regulation of
private sector activity ensures a net benefit to society. Decision making about
infrastructure investment is based on the net impacts measured by the host government
through project evaluation. The goals of a public project are to increase the well-being
of the community and to maintain or increase overall prosperity (Keating & Keating,
2013).
Project evaluation is a process of measuring impacts and risks of a project for
the purpose of evaluating and prioritising projects. This study considers project
18 Chapter 3: Literature Review
evaluation for the purpose of decision making by the governments for a public good.
Project evaluation is therefore a process to ensure that the project is beneficial with
respect to the public good. Mendel and Brudney (2014) define the public good as the
outcomes of public policy or private actions that create benefit or potential benefit
shared by everyone and arises within the moralistic, mission or values-driven work of
philanthropy. Examples of project outcomes for the public good include strong
economy, freeways, bridges and a healthy civil society (Mendel & Brudney, 2014).
For instance, the road project that is beneficial to the community is the project that
provides shorter travel time, shorter travel distance and fewer environmental impacts,
and serves as part of an effective transport network.
Bertoméu-Sánchez and Estache (2017) claim that the transport investment
decisions are more coherent in terms of providing economic benefits, with the
centralisation objectives than the strict concerns for mobility. For instance, the project
that mainly aims to improve accessibility is inefficient compared to the project that
aims to strength the local economy. This emphasises the importance of evaluating a
project with regard to a public good.
The scope of evaluation defines the impacts and risks that need to be considered
in the evaluation. For instance, Bauer and Szarata (2015) proposed a project evaluation
methodology of a transport corridor, which only reviews travel time and traffic volume
along it. The fewer the number of impacts to be included in project evaluation, the
simpler the methodology will be. However, it is difficult to select appropriate impacts
to be analysed and results of the evaluation can be limited. It is also inefficient to
conduct a number of analyses using different methodologies for a single infrastructure
item.
Table 3.1 summarises recent literature of toll road project evaluations. Toll road
projects have been evaluated in numerous articles, however many focus on traffic and
revenue forecasting (Bain, 2009; Li & Hensher, 2010; Welde, 2011), while there is
limited study in the literature regarding CBA for the purpose of evaluation of toll road
projects.
Chapter 3: Literature Review 19
Table 3.1 Evaluation of toll road projects found in academic literature
Author Study purpose Item evaluated
Aldrete, Bujanda
and Valdez (2012)
The study evaluated public revenue
financial risk exposure when transport
infrastructure is delivered through PPP.
Revenue risk exposure
Anas and Lindsey
(2011)
The study reviewed urban road pricing
theory on the basis of a toll road project.
Benefit and costs, public
transport, public acceptance
Bain (2009) The study reported the results from the
study of toll road forecasting
performance.
Traffic forecasts
Bel and Foote
(2009)
The study explored the implications
with respect to the public interest.
Impacts of toll road
concessions on the public
interest
Carpintero (2010) The study examined the gap between
the expected outcomes and the actual
results of toll roads.
Traffic forecasts, contract
management, government’s
role
Li and Hensher
(2010)
The study compared and discussed
actual traffic levels and forecasts.
Traffic forecasts
Liyanage and
Villalba-Romero
(2015)
The study measured overall success of
PPP toll road projects.
Qualitative measures from
project management,
stakeholder and contract
management perspectives
Mishra, Khasnabis
and Swain (2013)
The study proposed a framework to
analyse measures of effectiveness of
each entity involved in a toll road
project.
Capital cost, operation and
maintenance cost, toll
revenues and other payments
to the toll operator
Odeck (2008) The study evaluated the technical
efficiency of toll companies.
Payments to governments,
operational costs, traffic
volume, number of lanes, and
other productivity measures
Vassallo, Ortega
and de los Ángeles
Baeza (2012)
The study analysed the impact that the
economic recession had on the
performance of toll highway
concessions in Spain and the actions
Risk allocations and traffic
growth
20 Chapter 3: Literature Review
Author Study purpose Item evaluated
that the government adopted to avoid
the bankruptcy of the concessionaires.
Welde (2011) The study examined demand and
operating cost forecasting accuracy for
Norwegian toll projects by comparing
the forecasted and actual levels of
traffic and operating costs.
Traffic forecasts and
operating costs
Zhang (2008) The study developed models of market
entry, price, and capacity choices on
mixed-ownership networks to address
these research needs.
Market entry, price, and
capacity choices
Zhang, Bai, Labi
and Sinha (2013)
The study investigated in the decision
making process: economic efficiency of
privatisation and the protection of
public interest.
Financial transactions and
public interest
3.2 MEASURING IMPACTS USING COST-BENEFIT ANALYSIS
3.2.1 Impacts of Transport Facilities
Development of a new transport facility can impact the community in a number of
ways, directly and indirectly. An adequate transport network provides solutions to
traffic infiltration and high volumes into local areas, delays and congestion at major
intersections, and mixed function roads, where the traffic access function conflicts
with the traffic movement function (VicRoads, 2010). Connecting missing links and
improving accessibility of existing transport network contributes to significant
economic growth and regional development (European Conference of Ministers of
Transport, 2001). The most important influence categories of transport projects are
related to accessibility, safety and the environment which have both economic and
social impacts (van Wee & Tavasszy, 2008). Economic impacts particularly tend to
play a key role in project evaluation of a transport project. The costs of transport
projects are an immediate negative effect to public financial resources. Instead, many
of the benefits of transport improvements tend to gradually grow over the years after
the completion of the project. Additionally, although transport improvements tend to
Chapter 3: Literature Review 21
have large influences on growth patterns, the nature of the effect is significantly
dependent on the context of the investment (Funderburg, Nixon, Boarnet, & Ferguson,
2010).
3.2.2 Cost-Benefit Analysis Background Theory
Cost-Benefit Analysis (CBA) is the most commonly used project evaluation
methodology for major road projects (van Wee & Rietveld, 2014). CBA measures the
net impact of a project by monetising based on its market value and allocating the
impacts to benefit and costs (Rogers & Duffy, 2012; van Wee & Rietveld, 2014). The
project is economically viable when the monetary valuation of economic benefit
outweighs the full cost of the project (Rogers & Duffy, 2012). CBA is well studied in
academic literature, however the guidance on the treatment of tolls in CBA in extant
guidelines (Australian Transport and Infrastructure Council, 2016b; Queensland
Department of Transport and Main Roads, 2011; Rockliffe, Patrick, & Tsolakis, 2012)
is limited. For instance, Queensland CBA manual (Queensland Department of
Transport and Main Roads, 2011) advices to only include tolls as one of the factors
that influence road demands.
Broad impacts, including the impacts to the road users and the non-road users
can be included in CBA (Decorla-Souza, Lee, Timothy, & Mayer, 2013; Mackie,
Worsley, & Eliasson, 2014). This is particularly helpful when decision-makers need
to review the project from diverse viewpoints rather than making decisions based only
upon financial benefit. It is important to distinguish project evaluation from financial
assessment. Zhang, Bai, Labi and Sinha (2013) found in their financial analysis that
the host government is unlikely to gain sufficient benefit from toll road projects unless
traffic growth and toll prices are sufficient to provide financial benefit that is
equivalent to an upfront capital cost contribution. When CBA is used to evaluate a toll
road project, which would include transport impacts, the outcome of the evaluation
may differ from their study outcome. Transport impacts that are generally included in
CBA evaluation for a road project include the following monetised impacts; travel
time saving, vehicle operating cost saving (VOCS), crash cost saving (CCS),
environmental and external cost saving (EECS), capital cost, and operation and
maintenance (O&M) cost.
The result of CBA is generally represented as a Benefit-Cost Ratio (BCR), which
is the ratio of monetised benefit to monetised costs of the project over the planning
22 Chapter 3: Literature Review
horizon, each brought to present value. While a BCR greater than 1.0 theoretically
means that the benefits outweigh the costs and that the project provides a net benefit
to the community, decision-makers typically prefer the project with a higher BCR, in
order to accommodate a buffer against inherent inaccuracies in project evaluation
estimations, as well as the potential for unrealised assumptions and/or unknown
impacts that may arise during the planning horizon. BCR highly depends on the nature
of the project and can range from less than 1.0 to greater than 5.0.
The benefits of major transport projects often require a period of time to be
realised (Vickerman, 2017). This is due to the significant capital spending in early
years and the time required for the traffic demand to grow. When the length of planning
horizon is short, although there may not be enough transport benefits for the project to
be justified, it may still be due to its substantial residual value (RV). The longer the
planning horizon is the less RV and more other benefits to be realised. The justification
of a project should be made on the basis of its benefits to the community, such as travel
time savings, rather than only relying on its RV.
The CBA practices in different countries can vary significantly. This is due to
the differences in economic and financial settings in various countries. For instance, a
major transport project does not affect taxes in Australia, and therefore, taxes are not
captured in CBA of Australian projects. Tax revenue can instead be captured as part
of wider economic benefits (WEB) (Australian Transport and Infrastructure Council,
2017). However, taxes are generally considered in CBA of Danish projects, as seen in
(Manzo & Salling, 2016).
3.2.3 Critique of Cost-Benefit Analysis
Whilst CBA offers various advantages, such as abilities to present the analysis
outcomes in an empirical manner that is easy to interpret, and to capture travel time
saving, a number of limitations have been discussed in academic literature. Commonly
discussed are the issues associated with non-monetised impacts. Hwang (2016)
discussed monetisation issues of project impacts, particularly those non-market goods.
As has been highlighted, impacts are generally monetised on the basis of the market
values. Monetising non-market goods such as environmental impacts can be complex.
Inability to capture equity impacts is discussed in a number of studies (Hwang,
2016; Sumana & Hegde, 2014; Tsolakis, Patrick, & Thoresen, 2005; van Wee &
Chapter 3: Literature Review 23
Roeser, 2013; van Wee & Tavasszy, 2008). Although equity issues need to be taken
into consideration when evaluation a project, there are a number of difficulties in order
to capture equity impacts in CBA. First, equity impacts can be unique to each location
due to variations in the level of wealth of the residents in various locations (van Wee
& Roeser, 2013). Second, extensive data is required in order to capture equity impacts
in CBA (Sumana & Hegde, 2014). In order to effectively capture equity impacts in
project evaluation, tools other than CBA may need to be used. Alternative project
evaluation tools are discussed in a later section.
Other limitations that are highlighted in academic literature are the inability to
capture land use impacts and bias in CBA. For instance, a number of studies (Laird,
Nash, & Mackie, 2014; Tsolakis et al., 2005; van Wee & Tavasszy, 2008) argue that
standard CBA does not account for land use implications in demand forecasting, other
land use issues, overall performance of the economy, level of accessibility,
opportunities for interaction, and overall social functioning of the community. Some
of these impacts are non-monetised impacts, which cannot be captured using CBA,
however, others may be captured as part of wider economic benefits. Issues of wider
economic benefits are discussed in a later section. Moreover, Vejchodská (2015)
claims that many CBA practitioners lack knowledge in CBA and previously conducted
CBA are often biased and misleading. This should be further examined in the context
of CBA of Australian major road projects.
3.2.4 Wider Economic Benefits
As has been discussed, some of the impacts that are generally not accounted using
CBA can be captured through inclusion of WEB. Legaspi, Hensher and Wang (2015)
claim that there is an increasing awareness in the government policy community which
has escalated the focus on WEB to find ways of including them in allocation policy
criteria. The difficulty of estimating WEB is that the majority of WEB outputs are
generated from agglomeration and clustering, which requires a sophisticated land use
transport model to simulate how firms would respond to the transport improvement
and move their locations and how households would choose their residential locations
(Legaspi et al., 2015). To ensure transparency, consistency and robustness in WEB
estimation, reliability of data needs to be peer-reviewed, and rigorous data collection
and analysis are needed (Dobes & Leung, 2015). Vickerman (2017) further discusses
the weaknesses of WEB, including reliability of underlining assumptions. In Australia,
24 Chapter 3: Literature Review
government agencies are actively working on the development of guidelines with
regard to inclusion of WEB in CBA. The Australian Government has commissioned
consultants to work with the Australian Bureau of Statistics to undertake econometric
and economic modelling to obtain the set of parameter value estimates for publication
in the Guidelines (Australian Transport and Infrastructure Council, 2016a).
3.2.5 Discounting
A fundamental principle underlying economic analysis is that the value of money
depreciates over time (Sinha & Labi, 2007). Discount rate reflects the time value of
money as well as the premium that is required by investors to compensate them for the
systematic risk inherent in the project (Australian Department of Infrastructure and
Regional Development, 2013). Inflation and interest rate are generally accounted in
discount rate.
When calculating monetary benefits or costs at the particular point of year, any
past and/or future benefits and costs need to be calculated in present value terms. In a
monetary project evaluation methodology, such as CBA, all benefits and costs are
converted to present values, which represent the values of those benefits and costs at
the time of analysis or when construction has been completed. Year zero refers to the
year when initial costs, including construction costs are fully paid and the facility is
opened. Year one refers to the year when toll revenue of the opening year is counted
as income. The discount rate can have large impacts on benefits and costs that occur
in the long term (Koopmans & Rietveld, 2014; van Wee & Rietveld, 2014). The future
value depreciates exponentially with discount rate, therefore Benefit-Cost Ratio
(BCR) is calculated as:
𝐵𝐶𝑅 =𝑃𝑉(𝐵) + 𝑃𝑉(𝑅𝑉)
𝑃𝑉(𝐶𝑎𝑝 + 𝑂&𝑀)
(3.1)
Where:
𝑃𝑉 = present values, values are discounted using a discount rate
𝐵 = benefits of a project ($)
𝑅𝑉 = residual value of a project ($)
𝐶𝑎𝑝 = total capital cost over the whole planning horizon ($)
𝑂&𝑀= total operation and maintenance cost over the whole planning horizon
($)
Chapter 3: Literature Review 25
Contreras (2014) states that using one single discount rate for projects with
different characteristics is inadequate. Choosing the most appropriate discount rate to
be adopted in economic planning, project evaluation and public policy formulation is
a significant issue for researchers (Simonelli, 2013). In practice, either the discount
rate that the host government through its state treasury indicates at the time of analysis,
or the discount rate that is derived from the discount rate methodology that is
documented in the applicable government guidelines, is used. Discount rate varies for
Public-Private Partnership (PPP) projects. This is because, depending on the risk
allocations between public and private sectors, the systematic risk premium is adjusted
to reflect the proportion of risks that the public sector is bearing (Australian
Department of Infrastructure and Regional Development, 2013). For instance, a risk-
free rate is used when all of the systematic risks are borne by private sector (Australian
Department of Infrastructure and Regional Development, 2013). Estimating the
proportion of the systematic risks that are borne by the public sector can be complex.
Hence, it has been recommended that sensitivity and risks of the discount rate should
be tested. Additionally, Hwang (2016) argues that applications of discount rate become
controversial when the monetary value of human life or environmental value are
discounted.
3.2.6 Sensitivity Analysis
Sensitivity analysis is generally conducted as part of CBA to test the sensitivities of
input variables. Infrastructure Australia (2017) summarises common sensitivity tests
that can be conducted in CBA for business cases. As documented in Infrastructure
Australia (2017), the sensitivity analysis that is generally conducted in Australia is
one-way sensitivity analysis, where each input variable is varied, while others are held
unchanged. One-way sensitivity analysis can show which input variables are more
sensitive than others using tornado diagrams (Clemen & Reilly, 2013). However,
Saltelli and Annoni (2010), and Wang, Dyer and Hahn (2017) highlighted the
weaknesses of the one-way sensitivity analysis. One of the weaknesses is that it
assumes independence among the input variables (Wang et al., 2017). Wang, Dyer and
Hahn (2017) suggest probabilistic or multi-way sensitivity analysis, in order to test
sensitivities of dependent input variables. Additionally, risk profiles can be developed
using probability distributions (Clemen & Reilly, 2013).
26 Chapter 3: Literature Review
3.2.7 Alternatives to Cost-Benefit Analysis
Multiple-Criteria Decision Analysis (MCDA) is often used in practice in project
appraisal process, in order to account for non-monetised impacts. For instance, MCDA
was included in the feasibility assessment of Singleton Bypass (SNB) (AECOM
Australia, 2013). MCDA compares a number of alternatives or scenarios in terms of
specific criteria, which represent the feasibility of the objectives and sub-objectives of
decision makers and stakeholders participating in the decision-making process
(Brucker, Macharis, & Veisten, 2011). MCDA is generally used along with CBA in
practice (Rockliffe et al., 2012) and is also useful to assess transit accessibility at
strategic level (Hawas, Hassan, & Abulibdeh, 2016). The main limitation of MCDA is
the potential inconsistencies of weighting of each criterion due to subjective and
objective perspectives (Chen, Leng, Mao, & Liu, 2014).
There are various MCDA methodologies available depending on the required
inputs (Ishizaka & Nemery, 2012). A variety of MCDA methodologies can be found
in a number of recent studies (Barbosa et al., 2017; Chen et al., 2014; Hawas et al.,
2016; Macharis & Bernardini, 2015; MacHaris, Turcksin, & Lebeau, 2012; Salling &
Pryn, 2015).
A number of authors claim that the joint use of MCDA and CBA can overcome
their mutual weaknesses (Beria, Maltese, & Mariotti, 2012; van Wee & Roeser, 2013)
and the methodologies that combine MCDA and CBA have been proposed in a number
of previous studies (Ambrasaite, Barfod, & Salling, 2011; Gühnemann, Laird, &
Pearman, 2012).
Along with CBA, value for money (VFM) analysis is often conducted for Public-
Private Partnership projects. The usefulness of VFM is investigated in a number of
studies (Aldrete et al., 2012; Decorla-Souza et al., 2013). Key limitations of VFM is
that it only accounts for financial impacts to the host government and can include
irrelevant comparison of the economic resource costs (Decorla-Souza et al., 2013).
3.3 RISKS AND UNCERTAINTIES OF TOLL ROAD PROJECTS
The terms “risks” and “uncertainties” can be used interchangeably, however can also
be defined as different terms in some fields. For instance, Knight (2012) defines
“risks” as measurable factors that may or may not influence the project, while an
“uncertainty” is defined as an unmeasurable factor. This is particularly evident in
Chapter 3: Literature Review 27
capital cost estimation modelling, where project risks are modelled stochastically, and
capital costs are generally shown as P50 and P90 costs. The project risks are measured
and quantified as part of project contingencies in the stochastic cost modelling. This
study adopts Knight’s definitions and only considers “risks”. Considering
“uncertainties” or unmeasurable factors is beyond the scope of this study. The
following provides reviews of both risks and uncertainties of toll road projects.
The risks of toll road projects that need to be assessed in project evaluation can
be borne from many factors, such as cost and benefits estimations and monetisation,
political influence and toll price setting. Although there have been various approaches
in an attempt to address risks of projects in project evaluation in academic literature
(Mouter, Holleman, Calvert, & Annema, 2015; Shiau, 2014; Xu & Lambert, 2014),
Austroads advises addressing risks using one-way sensitivity analysis (Rockliffe et al.,
2012). Sensitivity analysis is a procedure in which the parameters are varied in an
arbitrary manner in an effort to ascertain the extent of changes in the economic
indicators as a result (Rogers & Duffy, 2012) and measures the sensitivities of input
variables. Mouter, Annema and van Wee (2014) claim that risks need to be
communicated more effectively in CBA and suggest testing sensitivities of a wider
variety of variables in CBA. The one-way sensitivity analysis provides a range of point
estimates of BCRs across different scenarios. However, it is unable to represent all
appreciable risks, nor a stochastic form of the output variables without incorporating
probability distributions in the sensitivity analysis.
The following discusses the risks that are particularly relevant to toll road
projects. These include risks in project cost estimations, traffic and revenue forecasts,
political influences and toll pricing. Impacts of risk allocations when a toll project is
delivered through a form of Public-Private Partnership (PPP) scheme are then
discussed.
3.3.1 Project Costs
When the cost of a road project is significantly large, tolling is an effective option to
recover the project costs. For instance, the project cost of the 4.6 km Legacy Way
tunnel in Brisbane, Australia, was AU$1.5 billion (ACCIONA Australia, 2015), while
the construction cost of the 6.8 km Clem Jones Tunnel also in Brisbane was AU$3.0
billion (Go VIA, 2015). Large-scale projects are often difficult to manage due to
complexity, which in turn is a result of large numbers of stakeholders’ involvement,
28 Chapter 3: Literature Review
considerable resources and time required for planning, design and construction, and
close media and political scrutiny. The common issues of large-scale projects include
cost overruns, project delays and benefit shortfalls (Bruijn & Leijten, 2008; Flyvbjerg,
2014).
Large-scale projects can produce significant wider economic benefits that are
greater than those accruing to users (Vickerman, 2008). These benefits can be added
to CBA as additional benefits to reinforce and justify projects that may not be
acceptable on the basis of the user benefits alone in practice (Vickerman, 2008). This
does not indicate that those projects should not proceed, although the greater the
number of wider economic benefits included in the CBA, the greater the risk contained
in the results of the CBA.
3.3.2 Traffic and Revenue Forecasts
Estimations of impacts of a major road project largely depend on traffic forecasts. The
forecasted traffic volume drives the outcomes of both economic and financial
evaluations of toll road projects. Additionally, Asplund and Eliasson (2016) claim that
transport investment and transport demand risks affect the CBA results the most. A
number of authors (Bain, 2009; Flyvbjerg, Holm, & Buhl, 2005; Li & Hensher, 2010)
claimed that traffic forecasts of toll roads tend to be overestimated. Rose and Hensher
(2014) claim that misestimating the value of travel time is the main contributor of
errors in traffic forecasting of toll roads, while Flyvbjerg et al. (2005) claims that
optimism bias is the key contributor of the errors.
Many toll road projects are Public-Private Partnership (PPP) projects that
contain a bidding process. The reported tendency for systematic overestimations was
also suggested by Bain (2009), and Vassallo and Baeza (2007), because of privately
financed toll road concessions being commonly awarded to bidding teams that submit
the highest traffic projections. Vassallo and Baeza (2007) claim that the traffic
forecasts that are produced by bidders contain notable bias towards overestimation,
compared to the projections produced by the host governments.
Accurate traffic volume estimations can only be derived from accurate travel
demand and system supply. Transport economics topics, such as demand modelling,
supply functions, market equilibrium, price elasticity, production costs and pricing are
therefore essential in traffic forecasting (Sinha & Labi, 2007).
Chapter 3: Literature Review 29
3.3.3 Political Influences
The number of political pressures that a project can face during the project appraisal
phase is highlighted by Mackie et al. (2014). Because toll road projects are often
initiated by a government, for large-scale projects, which can be significantly
influenced by political circumstances, elected officials could take opposition to tolling
seriously (Poole, 2011) and could view that the population at large is opposed to
tolling. According to Poole (2011), those who are affected fall into the following
groups:
• Tolled: financial disadvantage
• Tolled-off: those who divert to non-tolled parallel arterials
• Not-tolled: those who will be affected from increased traffic from the tolled-
off groups
For the tolled-off group, this applies when an existing facility is tolled. However, for
a new toll facility, toll road users can benefit from travel time saving by using the toll
road instead of alternative routes that may not be tolled. This is also the same for the
not-tolled group. When a new toll facility is built, some of the traffic that formerly
used the existing non-tolled alternative route will use the new facility; as a result, the
traffic on the existing route ought to decrease. Poole (2011) argues that the opposition
to paying tolls can be strong, as most car owners and road freight operators are opposed
to tolling.
However, this is not always the case for all toll road projects. As part of a large
transport network, toll road projects can provide significant benefits to road users and
non-road users as well as benefits to the surrounding community. Engel and Galetovic
(2014) claim that toll road projects can offer an opportunity to make tolls politically
acceptable, because tolls can reduce road congestion, ensure an adequate mix of public
and private transport, and finance maintenance and new infrastructure. There are
various benefits that a toll road can bring to the community, such as economic, land
use, social, cultural and transport benefits. Additionally, recent study (Mouter, 2017)
claims that many government officials have positive attitude towards CBA.
Offering various benefits of tolling across different types of supporters increases
a number of potential supporters to tolling (Yusuf, O’Connell, & Anuar, 2014). More
residents become supportive of tolls when revenue from tolling can be justified as a
30 Chapter 3: Literature Review
way to improve community life (Yusuf et al., 2014). CBA can be an effective tool to
measure net impacts to the community. The outcomes of CBA need to be
communicated effectively to the community to gain support from the community.
3.3.4 Toll Pricing
As the toll price increases, traffic volume along the toll road theoretically should
decrease (Low & Odgers, 2012). This phenomenon can be explained by price elasticity
of demand. It is rational to postulate that demand would decrease on a toll road when
there is increased traffic density, and therefore a reduced level of service on that road.
Drivers would avoid a congested toll road because it defeats the purpose of paying
tolls to save travel time. The rational motorists would not use the toll road if the
alternative, free route offered shorter travel time. This suggests the complexity of toll
road traffic modelling and the risk of toll price leads to risk in traffic forecasting.
Toll pricing strategies are well discussed in literature. A number of strategies
exist in toll pricing, such as travel time reliability maximising (Tirachini, Hensher, &
Bliemer, 2014), and toll revenue maximising (Joksimovic, Bliemer, & Bovy, 2005).
Beck and Hensher (2015) highlighted that a well-designed toll pricing scheme can
provide demonstrable time savings in the peak-time. Hensher and Bliemer (2014)
suggested a toll pricing scheme that reduces registration charges and peak-time pricing
that is distance-based to ensure sufficient toll revenues to the host government.
The possible objectives of road pricing generally are internalising external costs,
including welfare effects elsewhere in the economy, effective curbing of transport-
related problems, the generation of revenue and financing, and fairness (Verhoef,
2008). These objectives are not always compatible. For instance, welfare maximisation
and profit maximisation can create a significant conflict. In principle, the pricing
strategy that focuses on welfare maximises social surplus in the market (Verhoef,
2008). The successful deployment, both profitability and improvement of social
welfare of toll road pricing schemes, relies on individual project characteristics
(Tsekeris & Voß, 2008).
Pricing policies depend on the project objectives, which can be spawned from
the government’s policies. When a private sector sets the toll price, that price depends
on the market power exercised by the operator and road users (Button, 2010). The
operator can dictate the prices to a large extent when there is a single monopoly
Chapter 3: Literature Review 31
operator and numerous road users (Button, 2010). However, concession arrangements
could also dictate that the host government can regulate prices. Detailed price
modelling techniques are beyond the scope of this review.
3.3.5 Risk Allocation
In some toll road settings, when the toll road is owned, operated and/or maintained by
the private concessionaire, rather than earning revenue directly through receipt of tolls,
it receives payments from the host government using one of various methods
depending on the concession agreement. The following explains those payments
(Brocklebank, 2014):
• Shadow tolls avoid charging the users tolls; instead the host government is
responsible for paying the concessionaire according to traffic volume or
total travel distance along the road, in which case and specifically for traffic
modelling, the road is considered not to be tolled.
• Performance-based public sector payments may be paid by the host
government to the concessionaire.
• The concession can include guarantees of toll revenue. Toll revenue risk can
be shared with the host government through minimum revenue guarantees.
With minimum revenue guarantees, partial or full revenue risk is transferred
to the host government whereby it compensates the concessionaire for
shortfalls when the toll revenue received by the concessionaire is less than
a guaranteed amount.
These payments are forms of risk-sharing strategies. The risk to the public needs to be
properly assessed in project evaluation. However, the concession arrangement of a toll
road project can be complex and unique to each project.
The general principle is that exogenous traffic demand risk should be borne by
the party that is the best able to bear it (Engel, Fischer, & Galetovic, 2014). However,
Chung, Hensher and Rose (2010) suggest that many Australian toll road projects
experienced misallocation of risks due to the perception that certain risks are best left
alone to the party that is known to be “best able” to manage the risks. The assessment
of alternative risk allocations needs to be conducted as part of project evaluation of
toll road projects. Each toll road project is unique and the general principle may not be
applicable to all toll road projects.
32 Chapter 3: Literature Review
3.4 MONTE CARLO SIMULATION
All of the input variables in project evaluation are rarely certain (Rockliffe et al., 2012)
and each input variable contains various risks. Salling and Leleur (2011, 2017)
proposed a methodology that combines CBA and the Monte Carlo simulation to assess
risks of construction maintenance costs, travel time saving and crash cost saving.
The Monte Carlo simulation uses randomly generated values for the purpose of
forecasting, estimating or risk analysis (Mun, 2010). The Monte Carlo simulation of a
particular variable of interest requires a specific form of probability distribution and
its parameters. By applying a random number to the cumulative form of the
distribution, a value of the variable of interest can be generated randomly, in order to
present a particular trial. This algorithm can be repeated for numerous trials. The
Monte Carlo simulation, therefore, allows a predefined level of risk within the variable
to be portrayed.
The Monte Carlo simulation is a well-established methodology for assessing
risks of input variables. Table 3.2 summarises the use of the Monte Carlo simulation
for assessment of transport projects in recent literature. The impact of risks of various
parameters on a Benefit-Cost Ratio (BCR), crash counts, emissions, traffic volumes
and toll revenue was investigated by Fagnant and Kockelman (2012), whose study was
limited to minor road projects.
Chapter 3: Literature Review 33
Table 3.2 Use of the Monte Carlo simulation in assessment of transport projects
Literature
Measure of
economic
outcome
Study purpose Source of risks
modelled
Salling and
Leleur (2011,
2017)
BCR Presenting the Danish
CBA-DK software
model for assessment
of transport
infrastructure projects
Construction and
maintenance costs, travel
time saving and crash cost
saving unit price
Zhang, Bai, Labi,
and Sinha (2013)
Net present
value
Investigating
economic efficiency
of privatisation and
the protection of
public interest of toll
roads
Traffic growth, toll price and
discount rate
Ambrasaite,
Barfod, and
Salling (2011)
Total Rate of
Return
Introducing risk
analysis and the
Monte Carlo
simulation to the
weighting profile in
the MCDA
Weighting of criteria using
Multi-Criteria Decision
making approach
Fagnant and
Kockelman
(2012)
BCR Exploring the impact
of risks with the use of
hundreds of sensitivity
analyses to evaluate
highway capacity
expansion and toll
project scenarios
28 parameter sets of minor
transport projects
Khan (2013) Net present
worth
Identifying risk factors
in the lifecycle
analysis of a toll road
Toll revenue forecasts
3.5 SUMMARY
This review outlined the potential barriers to properly evaluate net impacts of a toll
road project to the community. This review also identified research gaps and
recommendations of how the barriers can be addressed.
34 Chapter 3: Literature Review
Project evaluation is a process to measure the net impacts of a project to the
community to ensure that the benefits of the decision made on the basis of the
evaluation outcomes outweigh the costs. The most commonly used project evaluation
methodology is Cost-Benefit Analysis (CBA). CBA measures and quantifies impacts
of a project and represents its outcome as a Benefit-Cost Ratio (BCR), which is a ratio
of the monetised benefits and monetised costs. It is important to distinguish CBA with
financial analysis. In the calculation of the CBA, the impacts that are not considered
in the financial analysis are considered, including various transport impacts.
Toll road projects may face various project risks that may or may not be similar
to the risks associated with non-toll road projects. For instance, a large-scale toll road
project contains the risks that are associated with any large-scale projects, such as cost
underestimations and benefit shortfalls. Other risks that are specific to toll road
projects include traffic, revenue, political and toll pricing risks. Particularly, the risk
associated with traffic and revenue forecasts have been studied by a number of authors.
These risks can be minimised and mitigated but can never be eliminated. The key to
the successful project evaluation is identifying and properly quantifying the risks so
that they are given appropriate considerations in the decision making.
3.5.1 Research Gaps
This review highlighted the limited studies conducted regarding the CBA for the
purpose of evaluation of toll road projects. CBA is a well-established project
evaluation methodology that can evaluate the project by considering various transport
impacts. As has been discussed, the outcome of CBA can differ from the outcome of
financial analysis. Whether the previous findings differ when CBA was used to
evaluate a toll road project require further investigation.
The sensitivities of project impacts and analysis inputs are generally tested in
CBA. However, one-way sensitivity analysis is limited by point estimations of
Benefit-Cost Ratio (BCR) across different scenarios. The representation of risks in
CBA requires improvements with empirical assessments and representations of risks.
Payment movements between entities of PPP toll road projects have been studied
in financial analysis (Mishra et al., 2013). Although not generally considered in CBA,
investigating payment movements and altering treatments of project impacts in the
CBA may extend the current knowledge. Particularly compelling is when the private
Chapter 3: Literature Review 35
operator collects tolls. Toll revenues are generally only included in CBA by affecting
travel behaviours and efficiencies in the transport system (Decorla-Souza et al., 2013).
This is rational when the host government obtains the toll revenues, because the end-
users who pay those tolls are constituents of the host government and therefore enjoy
the benefits of that toll revenue through government expenditure, including repayment
of project debt. However, the review found that there is a scarcity of investigating the
treatment of tolls in CBA. Along with various concession payments, the movement of
tolls can be considered in the CBA.
3.5.2 Recommendation
Unlike fully publicly delivered toll road projects, the risk-sharing arrangement of a
Public-Private Partnership (PPP) toll road project can be complex and unique to each
project. There are a number of risk-sharing strategies for toll road projects.
Additionally, along with the investigations of risk-sharing arrangements of a toll road
project, the discount rate that varies according to the risks that are borne by the host
government requires consideration. This is because the discount rate depends on the
risk allocations between public and private sectors (Australian Department of
Infrastructure and Regional Development, 2013). Discount rate and risk-sharing
arrangements of a PPP toll road project need to be considered together, as they
interrelate to each other.
The review highlighted the advantages and disadvantages of CBA and compared
it with other alternative project evaluation tools. Whilst CBA cannot account non-
monetised impacts, the comparison indicated that it is the best tool, in order to
effectively assess economic impacts and various delivery options. Literature (Laird et
al., 2014) claim that CBA is the most coherent and robust method available.
The Monte Carlo simulation is a well-established risk assessment methodology
and it may overcome the limitations of one-way sensitivity analysis conducted in the
CBA. An empirical representation of risks is an effective way to present them to the
decision-makers and the communities that may be impacted by the project.
Chapter 4: A Review of Cost-Benefit Analysis Practices 37
Chapter 4: A Review of Cost-Benefit
Analysis Practices
Previously conducted Cost-Benefit Analysis (CBA) for various major road projects
are reviewed in this chapter. This comparative case study compares CBA of toll road
projects with those of non-tolled road projects to highlight the limitations and
difficulties in existing practices of CBA for the purpose of evaluation of toll road
projects. This chapter first provides a brief introduction of the study cases and reviews
economic parameters that were used. It then reviews project cost and benefit
calculations, as well as residual value (RV) calculations. The variables that were tested
in sensitive analysis, selection criteria and the treatment of tolls in CBA are then
reviewed. Finally, discussions and findings are summarised.
4.1 THE STUDY CASES
Eight Australian major road study cases and two international study cases that include
four non-tolled roads and six toll roads were analysed in this study. These cases were
selected based on two key criteria: CBA reports are publicly available, and key
assumptions and parameters used in the analysis are described in the report. The
following describes background of each case.
4.1.1 Non-Tolled Roads
Horsham Bypass (HSB)
A study was commissioned by VicRoads, in order to select preferred route alignment
for a future Western Highway bypass in Horsham, Victoria (AECOM Australia, 2014).
The bypass was planned to allow for the future traffic growth along the Western
Highway that connects Melbourne and Adelaide (AECOM Australia, 2014). A CBA
was conducted to choose the preferred alignment based on the net present value and
the Benefit-Cost Ratio (BCR) (AECOM Australia, 2014). The lengths of option route
alignments were between 22 and 23.8 km (AECOM Australia, 2014).
M4 Corridor around Newport (MCN)
A 23 km new motorway section is proposed to be located in South Wales, UK and
includes a 440 m span cable stayed bridge across the River Usk (Arup, 2015). The
38 Chapter 4: A Review of Cost-Benefit Analysis Practices
proposed route will connect Castleton and Magor and provide an alternative route that
links east and west of Newport (Arup, 2014).
Singleton Bypass (SNB)
A study was commissioned by New South Wales (NSW) Roads and Maritime Services
(RMS), in order to select a preferred route alignment for a future New England
Highway bypass in Singleton, NSW (New South Wales Roads and Maritime Services,
2016). The bypass was planned to allow for future traffic growth along the New
England Highway, which connects Newcastle and the Upper Hunter region (New
South Wales Roads and Maritime Services, 2016). The preferred alignment was
chosen based on the measured economic benefit that was calculated in CBA (AECOM
Australia, 2012). The lengths of option route alignments were between 19.1 and 22.5
km (AECOM Australia, 2013).
West Petrie Bypass (WPB)
The section of Young’s Crossing Road is prone to flooding and is frequently inundated
by flood water (Arup, 2010a). The 1.92 km West Petrie Bypass (WPB) is a proposed
new road connecting Young’s Crossing Road and Dayboro Road to the west of Petrie,
which is a suburb of Moreton Bay Regional Council to the north of Brisbane (Arup,
2010b; GHD, 2013). A business case was produced for the alignment of the WPB that
was selected from the previous study (Arup, 2010a). The business case consists of
CBA of the alignment and the environmental and cultural heritage study (GHD, 2013).
4.1.2 Toll Roads
Airport Link (APL)
The Airport Link (APL) consists of a 6.78 km section of a tunnel and a motorway,
which is located in Brisbane (BrisConnections, 2016). APL is part of the corridor
designated as M7 and A7, which connects the south-west and north-east of Brisbane.
APL connects with other M7 elements of the Clem Jones Tunnel at its southern end
and the East West Arterial Road leading to Brisbane Airport and the Port of Brisbane
at its north-eastern end (BrisConnections, 2016). A major interchange at its southern
end also connects it with the Inner City Bypass expressway and Legacy Way (LGW),
and Bowen Bridge Road. A major interchange mid-tunnel connects it with Gympie
Road and Stafford Road, Kedron. CBA was conducted for the proposed alignment of
APL to assess the viability of the APL project by reviewing BCR calculated in the
Chapter 4: A Review of Cost-Benefit Analysis Practices 39
CBA and to review the integration of the Interim Northern Busway Project within the
APL project (SKM & Connell Wagner, 2006).
City Link (CYL)
City Link (CYL) is a 22 km motorway located in Melbourne and connects Monash
Freeway, West Gate Freeway and Tullamarine Freeway (Transurban, 2016a). CYL
consists of Western Link and Southern Link and provides access to Melbourne Airport,
Melbourne central business district (CBD) and Eastlink (Transurban, 2016a). A study
was conducted to review economic benefits of the CYL using CBA (The Allen
Consulting Group, 1996).
Gateway Upgrade Project (GUP)
Gateway Upgrade Project (GUP) is a 22.4 km upgrade of Gateway Motorway (M1) in
Brisbane, between Mt Gravatt-Capalaba Road at Wishart and Nudgee Road at Nudgee
(Connell Wagner, 2004). The motorway provides direct access to Brisbane Airport and
to Port of Brisbane Motorway (Connell Wagner, 2004). The GUP project consists of
lane widening of the existing infrastructure, a new bridge crossing, a new section of
motorway and a new interchange along the motorway (Connell Wagner, 2004). A
business case was developed to review economic impacts of the GUP project using
CBA (Connell Wagner, 2004).
Legacy Way (LGW)
Legacy Way (LGW), previously referred to as Northern Link, is located in Brisbane
and is a 4.6 km tunnel designated as part of the M5 corridor passing through the west
of Brisbane. It connects Centenary Motorway (Western Freeway) at Toowong with
the Inner City Bypass expressway at Herston (Brisbane City Council, 2010). The LGW
tunnel provides an access to Brisbane Airport, Royal Brisbane Hospital, Chermside,
Sandgate Road and Toowoomba (Queensland Motorways Management, 2016). CBA
was conducted as part of a business case of the LGW project to assess costs and
benefits of the project (Brisbane City Council, 2010).
Silvertown Tunnel (SLT)
Silvertown Tunnel (SLT) is a tolled tunnel that is about 2 km long and is proposed to
connect Greenwich Peninsula and Silvertown, UK (Jacobs, 2014b). SLT will be
directly connected to Blackwell Tunnel (A2), in order to ease traffic along the existing
tunnels under River Thames, UK. CBA was conducted to assess economic impacts of
40 Chapter 4: A Review of Cost-Benefit Analysis Practices
the SLT, however, different options, such as “do-nothing option”, were not considered
in the CBA (Jacobs, 2014a).
Toowoomba Bypass (TWB)
Toowoomba is located at the convergence of the Warrego, Gore and New England
Highways (Queensland Government, 2008). The road network in Toowoomba
provides interstate movements from Queensland to NSW, Victoria and Northern
Territory (Queensland Government, 2008). The Toowoomba Bypass (TWB) project
proposed a new, 42 km motorway that bypasses through movements from Toowoomba
City (Queensland Government, 2008). A business case was developed to assess the
needs of the project using CBA (Queensland Government, 2008).
4.1.3 Project Proponent and Owners
Major transport infrastructure projects are generally initiated by host government
bodies. Typically, they commission private consulting firms to undertake CBA. Table
4.1 summarises project proponents, representing their host governments.
Chapter 4: A Review of Cost-Benefit Analysis Practices 41
Table 4.1 Project proponent of the study cases (AECOM Australia, 2012, 2014; Arup, 2014;
Brisbane City Council, 2010; Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland
Government, 2008; SKM & Connell Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case State or country Project proponent
Horsham Bypass (HSB) VIC VicRoads
M4 Corridor around Newport (MCN) UK Welsh Government
Singleton Bypass (SNB) NSW NSW Roads and Maritime
Services
West Petrie Bypass (WPB) QLD Moreton Bay Regional Council
Airport Link (APL) QLD The State of Queensland and
Brisbane City Council
City Link (CYL) VIC VicRoads
Gateway Upgrade Project (GUP) QLD Queensland Department of
Transport and Main Roads
Legacy Way (LGW) QLD The State of Queensland and
Brisbane City Council
Silvertown Tunnel (SLT) UK Transport for London
Toowoomba Bypass (TWB) QLD The Australian Commonwealth
Government and the State of
Queensland
Table 4.2 summarises the operators of each tolled study case and its owners,
following the conclusion of its concession period. Generally, the infrastructure item is
owned by the operator and will be transferred back to the host government at the
conclusion of the concession period. A number of private firms are usually involved
in a single toll road project to design, build, operate, maintain and/or finance it. The
operators generally are responsible in financing the development of the project,
maintaining and operating the toll road in whole or part, and receiving toll revenues in
return. Toll roads are most often part of the state-controlled motorway network. All of
the study cases aside from LGW will be transferred to a state government at the
conclusions of their concession periods. In contrast, SLT was owned and operated by
public agencies.
42 Chapter 4: A Review of Cost-Benefit Analysis Practices
Table 4.2 Toll road operators and owners of the study cases (Brisbane City Council, 2015; Jacobs,
2014a; Queensland Department of Transport and Main Roads, 2015; Queensland Treasury, 2016;
Transurban, 2015a; VicRoads, 2015)
Case Operator Owner after the concession
APL BrisConnection The State of Queensland
CYL Transurban The State of Victoria
GUP Transurban The State of Queensland
LGW Transurban Brisbane City Council
SLT Transport for London Mayor of London
TWB Nexus Infrastructure The State of Queensland
4.2 ECONOMIC PARAMETERS
Significant variations in BCR values with different planning horizons was also
highlighted in Contreras’s study (2014). The value of discount rate and the length of
planning horizon can be key inputs in CBA. Table 4.3 summarises the discount rates
and planning horizon used for the study cases. The discount rates used for HSB and
CYL are significantly different, although they both are based in the same state. A three
percent difference of the discount rates can impact Benefit-Cost Ratio (BCR)
dramatically over the planning horizon of 30 years or longer. This suggests that the
risk allocations of HSB and CYL are noticeably different. MCN and SLT used variable
discount rates and the same length of planning horizon. Additionally, the discount rates
used in UK cases were noticeably lower than those used in Australian cases. The
discount rates that need to be used is defined by UK Cabinet Office (2017).
Chapter 4: A Review of Cost-Benefit Analysis Practices 43
Table 4.3 Economic parameters used in the study cases (AECOM Australia, 2012, 2014; Arup, 2014;
Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government, 2008; SKM & Connell
Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case State or
country Discount rate
Planning
Horizon
HSB Victoria 5 % 30 years
CYL Victoria 8 % 30 years
SNB NSW 7 % 30 years
WPB Queensland 7 % 30 years
APL Queensland 6.8 % 45 years
GUP Queensland 6 % 30 years
LGW Queensland 6 % 40 years
TWB Queensland 7.6 % 40 years
MCN UK 3.5 % for year 1 to 30 and 3 % for year 31 to
60
60 years
SLT UK 3.5 % for year 1 to 30 and 3 % for year 31 to
60
60 years
4.3 PROJECT COSTS
The project cost of each study case was estimated by each evaluator as a lump sum
payment and distributed over the construction period. In some of the study cases, the
operation and maintenance (O&M) cost was estimated individually. While for others,
simply one percent of the whole capital cost was entered as the O&M cost for the
whole planning horizon. For projects with relatively higher capital cost, such as tunnel
projects, capital cost and O&M cost, should be individually estimated, because their
proportions can vary between each project. For instance, with LGW, the proportions
of the individually estimated capital cost and O&M cost for the whole of planning
horizon were 81 percent and 19 percent respectively (SKM & Connell Wagner, 2008).
This shows considerable variations from the assumption that the O&M cost is one
percent of the whole capital cost. O&M cost was not considered in MCN case (Arup,
2014).
44 Chapter 4: A Review of Cost-Benefit Analysis Practices
4.4 PROJECT BENEFITS
Project benefits that was considered in the study cases include travel time saving,
vehicle operating cost saving (VOCS), crash cost saving (CCS) and other
environmental and external costs saving (EECS). Travel time saving was estimated
based on the assumption that by using the proposed infrastructure, travel time can be
saved, which then can be converted to a dollar amount. VOCS, CCS and EECS were
estimated based on the assumptions that by using the proposed infrastructure, travel
distance can be saved. This translates to lower vehicle operating cost, fewer crashes,
and fewer impacts upon the environment. The saved travel distance is then used to
estimate the VOCS, CCS and EESC in dollar amount. Comparisons of sources of these
cost estimates and the methodologies to model travel time and travel distance are
beyond the scope of this study.
Along with travel time saving, VOCS, CCS and EESC, costs of incident delays,
travel time variability and delays during construction were considered for SLT (Jacobs,
2014a). However, the final benefits only included travel time saving and VOCS
(Jacobs, 2014a). Unit prices were not documented in the report for MCN, while travel
time saving and VOC were accounted as benefits (Arup, 2014). Impacts during
construction and maintenance and revenues were also included as benefits for MCN
case (Arup, 2014).
Not all input data were documented in the Cost-Benefit Analysis (CBA) reports
of the study cases. The inputs that were not documented are shown as “unknown” in
the following sections, but this does not indicate that they were excluded in the CBA
calculation. In fact, all of travel time saving, VOCS, CCS and EECS were included for
all of the study cases aside from the WPB. All costs are shown with conversion to 2016
Australian dollars or 2016 British pounds for equitable comparison, using the inflation
methodology of the Reserve Bank of Australia (2017) and the Bank of England (2017)
in the following section. British pounds were converted to Australian dollars using the
exchange rates published by the London Stock Exchange (2017), which are shown in
brackets.
4.4.1 Travel Time Saving
Travel time saving was calculated based on the vehicle hours travelled saving and
travel time unit price. The travel time unit price estimation methodology was not
Chapter 4: A Review of Cost-Benefit Analysis Practices 45
documented for the study cases. For all of the study cases, the travel time unit price
was estimated for light vehicles (LV) and heavy vehicles (HV) separately, and costs
for private time and working time were also estimated. Table 4.4 shows the travel time
unit prices used in the study cases. The unit prices used in the study cases are relatively
consistent.
Table 4.4 Travel time unit price per hour in 2015 dollars (AECOM Australia, 2012, 2014; Arup,
2014; Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government, 2008; SKM &
Connell Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case LV (per veh-h) HV (per veh-h)
HSB $15.49 for non-work trips
$49.54 for in-work trips
$34.82 for rigid HV
$73.60 for articulated HV
MCN Unknown
SNB $37.85 $49.76
WPB $29.85 for both LV and HV
APL $22.57 for non-work trips
$63.21 for in-work trips
$37.45-$42.42 for rigid HV
$58.68-$70.21 for articulated HV
CYL $21.04 for both LV and HV
GUP Unknown
LGW $20.10 for non-work trips
$61.99 for in-work trips
$41.04
SLT £8.01 ($13.03) for both LV and HV
TWB Unknown
4.4.2 Vehicle Operating Cost Saving (VOCS)
In the study cases, various VOCS unit prices were used for different vehicle types and
travel speeds. Table 4.5 summarises VOCS unit price used in the study cases. The unit
prices shown in Table 4.5 are for vehicles travelling at 80 km/h. The CBA conducted
for WPB showed some technical errors and VOCS was excluded from the CBA
calculation (GHD, 2013). The unit prices of vehicle operating cost used in the study
cases are also relatively consistent.
46 Chapter 4: A Review of Cost-Benefit Analysis Practices
Table 4.5 Vehicle operating cost saving unit price per km in 2015 dollars (AECOM Australia, 2012,
2014; Arup, 2014; Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government,
2008; SKM & Connell Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case LV (per veh-km) HV (per veh-km)
HSB $0.25 $1.33
MCN Unknown
SNB $0.33 $1.14
WPB Excluded
APL $0.18 for cars
$0.36 for light commercial vehicles
$1.40
CYL Unknown
GUP Unknown
LGW Unknown
SLT Unknown
TWB Unknown
4.4.3 Crash Cost Saving (CCS)
Crash rate theoretically should be different between urban and rural setting and also
between roads and tunnels. Motorways particularly should have different crash rates
to major arterial roads since they are uninterrupted flow facilities. The variations in the
unit price of crash cost can be due to various methodologies for estimations, but ought
to be similar for the same type of infrastructure in the same state. Table 4.6 summarises
the CCS unit price used for the study cases. The CCS was calculated as the product of
crash cost, crash rate and vehicle kilometres travelled saving in three cases (AECOM
Australia, 2012, 2014; GHD, 2013). The estimation of the unit price of the CCS was
not documented for the rest of the five cases. The unit prices used for HSB, SNB and
WPB showed noticeable variations. The crash cost used for HSB only considered
casualties. The crash rate used for SNB was significantly higher than the other two
cases. HSB and SNB are both rural bypass projects and the crash rate for the two
projects should be similar. The CCS unit price used for APL is significantly lower than
the other cases. This shows either an error with estimation of the CCS unit price or the
fact that crash rate is assumed to be lower for tunnels.
Chapter 4: A Review of Cost-Benefit Analysis Practices 47
Table 4.6 Crash cost saving unit price in 2015 dollars (AECOM Australia, 2012, 2014; Arup, 2014;
Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government, 2008; SKM & Connell
Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case Crash cost (per crash) Crash rate (per veh-
million km)
Total CCS unit price
(per veh-million km)
HSB $268,026 0.11 $29,482
MCN Excluded
SNB $2,337,366 3.44 $8,040,538
WPB $3,513,667 0.31 $1,075,610
APL Unknown Unknown $23,920
CYL Unknown
GUP Unknown
LGW Unknown
SLT Excluded
TWB Unknown
4.4.4 Environmental and External Cost Saving (EECS)
There are considerable variations in the types of costs that were included in the EECS
in the study cases. The methodology of estimation of the EECS unit price was not
clearly documented in any of the study cases (AECOM Australia, 2012, 2014; Connell
Wagner, 2004; GHD, 2013; Queensland Government, 2008; SKM & Connell Wagner,
2006, 2008; The Allen Consulting Group, 1996). Table 4.7 summarises the types of
costs that were included in the EECS unit price for each case. Austroads states that all
of these impacts shown in Table 4.7 should be considered in CBA (Tan, Lloyd, &
Evans, 2012). Although GHD (2013) mentioned that the EECS unit price includes air
pollution, greenhouse gas emission (GHG), noise pollution, water pollution, impact on
nature and landscape, urban separation, and upstream and downstream costs, only the
GHG, and air and noise pollutions were accounted in their EEC calculation. The whole
of EECS was not considered in the CYL case (The Allen Consulting Group, 1996).
The types of EECS considered in the GUP case were not documented (Connell
Wagner, 2004). External costs were only considered in the TWB case, however the
48 Chapter 4: A Review of Cost-Benefit Analysis Practices
types of costs that were considered were not documented (Queensland Government,
2008).
Table 4.7 Environmental and external cost types (AECOM Australia, 2012, 2014; Arup, 2014;
Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government, 2008; SKM & Connell
Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case GHG Air
pollution
Noise
pollution
Water
pollution
Nature
and
landscape
Urban
separation
Upstream
and
downstream
HSB ✓ ✓ ✓ ✓ ✓ ✓ ✓
MCN Excluded
SNB ✗ ✓ ✓ ✓ ✓ ✓ ✓
WPB ✓ ✓ ✓ ✗ ✗ ✗ ✗
APL ✗ ✓ ✓ ✓ ✗ ✗ ✗
CYL Excluded
GUP Unknown
LGW ✓ ✓ ✓ ✓ ✓ ✓ ✓
SLT Excluded
TWB Only externalities are included
Table 4.8 summarises the unit prices used to estimate EECS. Although the total
EECS unit price for HSB included GHG and other environmental and external costs,
the document prepared for the HSB case (AECOM Australia, 2014) does not specify
the values of other environmental and external costs, which are unknown. Separate
unit price for LV and HV of EECS were estimated in the APL case, however the unit
price for HV was not documented (SKM & Connell Wagner, 2006). There are
noticeable variations in the unit prices used to estimate EECS between all study cases.
The unit price for HV has more significance than those for LV in CBA calculations.
Chapter 4: A Review of Cost-Benefit Analysis Practices 49
Table 4.8 Environmental and external cost saving (EECS) unit price per km in 2015 dollars (AECOM
Australia, 2012, 2014; Arup, 2014; Connell Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland
Government, 2008; SKM & Connell Wagner, 2006, 2008; The Allen Consulting Group, 1996)
Case LV (per veh-km) HV (per veh-km)
HSB $2.89 for GHG
Other EEC Unknown
$6.50 for GHG cost of rigid HV
$3.45 for GHG cost of articulated HV
Other EEC Unknown
MCN Excluded
SNB $0.07 $0.43
WPB $0.0236 for GHG for both LV and HV
$0.0299 for air pollution for both LV and HV
$0.0098 for noise pollution for both LV and HV
APL $0.0102 for noise pollution
$0.0308 for air pollution
$0.0045 for water pollution
Unknown
CYL Excluded
GUP Unknown
LGW $0.116 $8.35
SLT Excluded
TWB Unknown
4.5 RESIDUAL VALUE
There was considerable variation in the treatment and calculation of RV. RV
represents the value of the asset at the end of the planning horizon and is added in
Cost-Benefit Analysis (CBA) as a benefit. The expected economic life of a road is 40
to 60 years, a concrete bridge is 120 years and a tunnel is 100 years (Australian
Transport Council, 2006b). There may be minor variations in these values, however
the lifespan of an asset should be equal to its design life. Table 4.9 summarises
assumed lengths of lifespans for the infrastructure items of the study cases.
50 Chapter 4: A Review of Cost-Benefit Analysis Practices
Table 4.9 Assumed lifespan of the study cases (AECOM Australia, 2012, 2014; Arup, 2014; Connell
Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government, 2008; SKM & Connell Wagner,
2006, 2008; The Allen Consulting Group, 1996)
Case Assumed lifespan of the infrastructure
HSB RV was not considered
MCN RV was not considered
SNB RV was not considered
WPB 50 years for road structure and 100 years for bridge structures
APL Lifespan was assumed to be equal to the length of concession period of 45
years
CYL RV was not considered
GUP Unknown
LGW 40 years
SLT RV was not considered
TWB Unknown
The infrastructure values were assumed to depreciate linearly over their lifespans
for WPB, APL and LGW cases. The CBA for APL assumed that the value of the APL
will be zero at the conclusion of its concession period. The CBA for LGW also
assumed that the value of the LGW will be zero after 40 years. This can be true from
the private sector’s perspective, as generally the infrastructure will be transferred back
to the host government at the conclusion of the concession period. From the host
government’s perspective, the infrastructure will be owned by the public and there
should always be some RV at the conclusion of the concession period, unless the life
of the infrastructure item has ended and it needs to be fully replaced. Even so, present
worth of an RV is generally very small. RV was not considered in the CBA of HSB,
MCN, SNB, CYL and SLT (AECOM Australia, 2012, 2014; Jacobs, 2014a; The Allen
Consulting Group, 1996). This can indicate that the RV was assumed to be zero at the
end of the planning horizon. This argument also suggests that when the planning
horizon is shorter than the concession period, the infrastructure item is still owned by
the private concessionaire and the RV at the end of planning horizon would be zero.
When the planning horizon is longer than the concession period, RV still applies at the
Chapter 4: A Review of Cost-Benefit Analysis Practices 51
end of the planning horizon instead of the conclusion of concession period, as the
depreciation of the value of the infrastructure continues.
4.6 SENSITIVITY ANALYSIS
Table 4.10 summarises the sensitivity analyses that were performed for the study cases.
Sensitivity analysis was not performed for CYL and GUP, and therefore was not
considered in the decision making process. The type of sensitivity analysis that was
conducted for the study cases was one-way. The inputs that were tested in the
sensitivity analysis varied between cases. Theoretically, inputs that form the basis of
calculated impacts, which are traffic growth rate and forecasted traffic volume, should
at least be tested. Capital cost of major transport projects tend to be underestimated
(Flyvbjerg, 2014), and therefore should also be tested in sensitivity analysis. Various
discount rates are commonly tested, as shown in Table 4.10.
52 Chapter 4: A Review of Cost-Benefit Analysis Practices
Table 4.10 Sensitivity analysis conducted in the study cases (AECOM Australia, 2012, 2014; Connell
Wagner, 2004; GHD, 2013; Jacobs, 2014a; Queensland Government, 2008; SKM & Connell Wagner,
2006, 2008; The Allen Consulting Group, 1996)
Case Traffic
growth rate
Forecasted
traffic
volume
Discount
rates Capital cost Other
HSB ± 10 % ± 10 % Not tested Not tested
MCN Low, high
and no
growths
Not tested Not tested Not tested When tolls along
nearby motorways
were removed
SNB Higher and
lower than
forecasted
± 20 % 4 % and
10 %
± 20 % Recalculated crash
cost saving
WPB Not tested Not tested 4 % and
10 %
Not tested
APL Not tested Not tested 5.5 % Recalculated
with various
risks
1 % higher population
growth
CYL Not performed
GUP Not performed
LGW Not tested Not tested 4 % and 8
%
Not tested na
SLT Not
performed
TWB Not tested Not tested 3.5 % and
6.5 %
± 20 % ± 20 % of travel time
saving and vehicle
operating cost; and ±
50 % of crash rate
Table 4.11 summarises the variables that the extent guidelines recommend
performing sensitivity analysis on. Australian Transport and Infrastructure Council
(2016b) recommends the sensitivity analysis suggested in the Austroads guidelines
(Rockliffe et al., 2012).
Chapter 4: A Review of Cost-Benefit Analysis Practices 53
Table 4.11 Recommended sensitivity analysis in the Australian guidelines
Guideline
Traffic
growth
rate
Forecasted
traffic
volume
Discount
rates
Capital
cost Other
Austroads
(Rockliffe et
al., 2012)
± 2 % ± 10-20 % Not
tested
± 20 % Proportion of HV,
average car
occupancy rate,
induced traffic
estimate, traffic speed
and crash rate
Infrastructure
Australia
(2017)
± 2 % ± 5 % 4 % and
10 %
± 20 %
and/or P50
and P90
costs
Project specific
benefits, planning
horizon, proportion of
HV, and traffic
generated or diverted
by the initiative
As shown in Table 4.10 and Table 4.11, there are some similarities to the
sensitivity analysis that was conducted for each case and the recommended sensitivity
analysis. However, all cases except SNB, there are large variations between what is
performed and what is recommended. It can be speculated that the variation can be due
to technical limitations and/or differences in the business case requirements in each
state. Additionally, this also suggests that less focus may be placed on the sensitivity
analysis than the key CBA results, such as BCR and NPV. As discussed, the risks of a
project are generally only assessed using sensitivity analysis in CBA in practice, which
indicates the lack of risk assessment in the CBA practices.
4.7 SELECTION OF PREFERRED OPTION
As part of the whole project evaluation for all of the study cases, although other
considerations, such as wider economic benefits and other intangible factors were
considered as part of the whole project evaluation of all of the study cases, the outcome
of Cost-Benefit Analysis (CBA) was represented using net present value and Benefit-
Cost Ratio (BCR). A BCR below 1.0 was determined for HSB (AECOM Australia,
2014), while BCRs below 2.0 were determined for SNB, WPB, APL, LGW and SLT
(AECOM Australia, 2012; GHD, 2013; Jacobs, 2014a; SKM & Connell Wagner,
54 Chapter 4: A Review of Cost-Benefit Analysis Practices
2006, 2008). A BCR greater than 2.0 was determined for MCN (Arup, 2014). None of
the study cases that resulted in BCR below 2.0 were discontinued, suggesting that other
major factors that were not accounted for in CBA were considered in the justification
process of these projects.
4.8 TREATMENT OF TOLLS
Of the six toll road project cases, tolls were considered as a financial transfer between
the host government and the toll road users and so were excluded in Cost-Benefit
Analysis (CBA) calculations of APL, CYL, GUP and LGW cases. Various toll prices
were applied in traffic forecast modelling and traffic volumes, and proportions of HV
were estimated for each different toll price in the CBA for TWB case (Queensland
Government, 2008). Tolls were considered as the cost to the community in SLT case
(Jacobs, 2014a), although a public agency will be collecting the tolls. Costs associated
with toll collection were accounted in cost calculation as well (Jacobs, 2014a). Tolls
were considered as a financial transfer in the TWB CBA, however they were included
in modelling as a factor that influenced traffic volume forecasts (Queensland
Government, 2008). This is consistent with previous study (Decorla-Souza et al.,
2013). It is reasonable to argue that in all of the study cases, tolls were considered as
a financial transfer because they replace the capital, operating and maintenance costs
of the project that would have otherwise been borne by the public through the host
government if the project were a non-tolled, public road. Philosophically, this manner
of treating cost is the most significant assumption that was made in the CBA-based
project evaluations of the tolled study cases.
4.9 DISCUSSION
Some technical inconsistencies exist between the Cost-Benefit Analysis (CBA)
methodologies followed in the study cases. For instance, CYL was the only case that
included the off-road benefit in its CBA calculation. The methodology of the
estimation of the off-road benefit was not documented (The Allen Consulting Group,
1996). The inconsistencies between Australian cases and UK cases were significant.
This can be due to the differences in guidance of road authorities with regard to CBA
in different countries. The following discusses possible causes of the inconsistencies.
First, every consulting firm that would be conducting CBA for host government
agencies has some level of limitations with their resources, including labour, money
Chapter 4: A Review of Cost-Benefit Analysis Practices 55
and time. For instance, a practitioner may have to use values derived from other studies
to conduct CBA in practice, as it is common for the practitioner to produce the analysis
in a short time-frame (Soh, 2012). The quality of the analysis can highly depend on
the resources available and time constraints.
Second, the guidelines of project evaluation and CBA range from the complex,
to those lacking in depth or consistency. For instance, the discount rate methodology
shown in the discount rate guidelines (Australian Department of Infrastructure and
Regional Development, 2013; New South Wales Treasury, 2007) suggests the use of
various discount rate methodologies for projects with different risk allocations. It
sometimes can be difficult for the firm to first select the applicable methodology and
then to conduct the required risk analysis while identifying the appropriate discount
rate to use.
Third, there is a possibility that the host government is not necessarily expecting
comprehensive CBA, particularly when there are significant intangible factors
involved in the project. For instance, for a bypass project in a rural region, the Benefit-
Cost Ratio (BCR) that was derived from the CBA may not necessarily completely
decide viability of the project. Some items considered to be intangibles in the CBA,
such as community sentiment, may drive its decision making. This was also evident in
the cases. Despite CBA being capable of capturing many project impacts, monetising
certain impacts, particularly related to community issues, can be difficult.
Fourth, decision making for large-scale projects, such as transport projects can
be complex work, which requires consideration of monetary and non-monetary
impacts as well as various project risks and other intangible factors. A large part of
what makes project evaluation of transport projects difficult is the complexity of
transport planning itself. Forecasting and modelling the impact of adding a new
transport infrastructure into an existing network increases with the complexity of the
network itself. When evaluating a single road, the worthiness of the road depends on
how it acts as part of the whole transport network.
Additionally, economic analysis reports of many study cases had poor
transparencies. Input parameters and detailed calculations were not all documented.
This can be possibly due to the use of computer software to conduct CBA calculations.
Many practitioners may have failed to document key information of the calculation in
the report. For instance, for CBA of a major road project, input parameters, list of
56 Chapter 4: A Review of Cost-Benefit Analysis Practices
benefits that were accounted, the manuals or guides that were referred, and how
discount rate was determined should at least be documented.
Also important is the opening year of the road. As the time value of money
diminishes with the size of discount rate used, the benefit gained in the first few years
will be more significant than the benefit gained later years with a higher discount rate.
If a road is built as an initial component of a larger transport planning initiative, for
instance a network of toll roads in an urban area, the full benefit of that road in terms
of its use may only be realised once other components of the network are opened and
operating in unison. Unfortunately, the discounted benefit and therefore CBA of that
initial road would be expected to be relatively less than its subsequent partner
component roads due to a longer ramp-up period. For a road to perform at its maximum
capacity, the surrounding transport network needs to be working effectively with the
road. This circumstance is referred as the toll road network founder disadvantage in
this study. The improvement in ability to accurately forecast traffic as the network
develops compounds this circumstance. A case in point is the Brisbane toll tunnel
network. Clem Jones Tunnel opened two years prior to APL and five years prior to
LGW (BrisConnections, 2016; Transurban, 2015b, 2016d). LGW has been the most
successful link in the network since its opening, while the first two components
suffered from limited demands initially.
It has been highlighted that the estimation of RV at the end of the planning
horizon depends on the scope of the evaluation. When the design life of the
infrastructure is larger than the planning horizon, and the infrastructure will be
transferred back to the host government at the conclusion of its concession period, RV
should be included in CBA as a benefit. The review of the study cases revealed that
RV of some of the study cases was treated in this manner. In particular, for tunnel
projects, the longer design life and higher construction cost of the tunnel structure
leaves a larger RV at the end of the planning horizon. Therefore, RV of tunnels can
significantly influence the outcome of CBA.
The treatment of tolls in CBA raises questions when impacts to the community
are concerned. As illustrated by the tolled study cases, tolls are generally considered
as a financial transfer and enter into CBA calculations only to the extent that they cause
a change in micro-economic behaviour (Decorla-Souza et al., 2013). As discussed
above, it is reasonable to argue that this is because they replace the capital, operating
Chapter 4: A Review of Cost-Benefit Analysis Practices 57
and maintenance costs of the project that would have otherwise been borne by the
public through the host government if the project were a non-tolled, public road.
However, this is only completely truly realistic, if the transfer is internal to the public
purse, for instance when the host government on behalf of the public pays for the
infrastructure item, collects the revenue, and bears all of the project risk during its
lifetime. An example of this case was when Queensland Motorways, as a Queensland
Government, owned and operated a tolled motorway, Gateway Motorway in Brisbane,
before the concession of the motorway was later purchased by Transurban.
If the opposite extreme is considered, whereby the toll road is designed, built,
operated and financed by private sector firms, the influences of the impacts that are
borne by the private sector need to be carefully considered. If such impacts are
recouped in a commercial environment by way of charging the end-users, who in the
case of a toll road are normally members of the community, it can be argued that those
end-user charges should be counted as the societal cost impacts in CBA. Meanwhile,
while the project’s capital, operating and maintenance costs are borne by the private
sector rather than the host government, these latter costs should be excluded from the
CBA because they are financial impositions that are contained within the private sector
entity’s enterprise of offering its product, rather than as an end-user societal cost. The
majority of toll road projects in Australia do not fit into either extreme, which makes
the treatment of tolls in CBA a complex consideration. Further investigation is needed
to explore how tolls should be treated, and how concession arrangements, such as
minimum revenue guarantees should be considered.
The UK CBA manual (UK Department of Transport, 2014) states that user
charges, including tolls, need to be included in CBA calculations, however, toll
revenues require careful considerations in the calculation. As highlighted, tolls were
accounted as costs in the CBA calculation of the SLT case. This indicates that the CBA
practice significantly differ between Australia and UK. Treatments of tolls and toll
revenues may need to differ between projects with various risk-sharing arrangement,
as has been discussed previously.
As has been discussed, discount rate varies depending on the risk-sharing
arrangement between public and private sectors, and significantly influence the
outcome of CBA. As illustrated in the discussion of the treatment of tolls in CBA, the
risk allocation is also directly linked to the allocation of impacts. The risk of a project
58 Chapter 4: A Review of Cost-Benefit Analysis Practices
can play a key role in decision making and needs to be measured precisely and
empirically. There was limited coverage of risk in all of the study cases.
In contrast, discount rate methodology that is used in UK does not account the
risk-sharing arrangement. For any projects, UK Cabinet Office advises to use the same
discount rates (UK Cabinet Office, 2017). Additionally, RV is generally excluded in
CBA calculation for projects with the planning horizon longer than 60 years in UK
(UK Department of Transport, 2014). The UK CBA manual (UK Department of
Transport, 2014) does not consider when the length of lifespan of the asset is longer
than 60 years. These indicate that discount rate and RV calculation practices differ
between Australia and UK.
This case study revealed a limitation of the extant CBA methodology, which is
to clearly display the range in risk that the project may face. Estimating appropriate
discount rate for Public-Private Partnership (PPP) projects can also be a complex task
due to the complexity of estimating risk-sharing between public and private sectors.
For instance, the sensitivity analysis that was conducted for each case did not show the
project risks in an empirical manner. As an example, representation of the risk of a
Benefit-Cost Ratio (BCR) being below 1.0 that is represented using percentages would
be extremely useful in the decision making process.
4.10 SUMMARY
This case study found that for many toll road projects in Australia, tolls were
considered as a financial transfer and were excluded in Cost-Benefit Analysis (CBA).
However, further consideration showed that tolls should not necessarily simply be
excluded as costs, and the treatment of tolls should differ between different toll road
projects. Tolls were considered as the cost to the community for the UK case, although
the tolls will be collected by a public toll operator (Jacobs, 2014a). Further study is
needed to investigate the mechanisms of the treatment of tolls in CBA and various risk
allocations. The study also identified limitations of the extant CBA methodology to
evaluate toll road projects. The representations of project risks in cases were somewhat
limited. Empirical based representations of project risks would assist effective decision
making. For instance, measuring the risk of Benefit-Cost Ratio (BCR) using statistical
measurements, such as probability of failure would be significantly useful for decision
making.
Chapter 4: A Review of Cost-Benefit Analysis Practices 59
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 61
Chapter 5: Incorporating Stochastic
Approach in Cost-Benefit
Analysis
The risk arrangement of a toll road project can be unique to each project and assessing
risk is crucial in the decision making of the project. Cost-Benefit Analysis (CBA) is
the most commonly used to evaluate major road projects, including tolled and non-
tolled roads (van Wee & Rietveld, 2014). The decision making using CBA relies on a
single, deterministic Benefit-Cost Ratio (BCR) and one-way sensitivity analysis.
However, the interpretation of the impacts and risks using a single, deterministic BCR,
even with one-way sensitivity analysis, is limited by the point assumptions that are
made in the monetisation of impacts. There is a paucity of study in the literature
regarding CBA to measure the net impacts of a toll road project and the representation
of risk in an empirical manner. This chapter examines how risks of various input
variables can be reflected in the CBA outcome. It is hypothesised that the risks that
influence net impacts to the community can be quantified using the Monte Carlo
simulation in CBA. A toll tunnel project case is synthesised based on the overarching
characteristics of a selection of recent toll tunnel projects in Brisbane, Australia, in
order to examine how various risks of a toll road project are quantified using a
stochastic BCR distribution.
5.1 COST-BENEFIT ANALYSIS CALCULATION
Transport benefits that are generally assessed in CBA of a major road project include
travel time, vehicle operating cost saving (VOCS), crash cost saving (CCS), and
environmental and external cost saving (EECS). Each saving is generally estimated
individually for light vehicles (LV) and for heavy vehicles (HV). An annualised
project benefit at year 𝑦 for Monte Carlo trial 𝑗 is given as follows:
62 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
𝐵𝑗,𝑦 = (𝐴𝐴𝐷𝑇𝑗,𝑦 × 365)
× {∑(𝑇𝑇𝑗,𝑘 × 𝑃(𝑘)𝑗 × 𝑉𝐻𝑇𝑆𝑗)
+∑(𝑉𝑂𝐶𝑗,𝑘 × 𝑃(𝑘)𝑗 × 𝑉𝐾𝑇𝑆𝑗) + (𝐶𝐶𝑗 × 𝑉𝐾𝑇𝑆𝑗)
+∑(𝐸𝐸𝐶𝑗,𝑘 × 𝑃(𝑘)𝑗 × 𝑉𝐾𝑇𝑆𝑗)}
(5.1)
Where:
𝐵𝑗,𝑦 = total annual project benefit at year 𝑦 for trial 𝑗 ($)
𝐴𝐴𝐷𝑇𝑗,𝑦 = average annual daily traffic at year 𝑦 for trial 𝑗 (veh/d)
𝑇𝑇𝑗,𝑘 = travel time unit price for the vehicle type 𝑘 for trial 𝑗 ($/veh-h)
𝑉𝑂𝐶𝑗,𝑘 = vehicle operating cost unit price for the vehicle type 𝑘 for trial 𝑗
($/veh-km)
𝐶𝐶𝑗 = crash cost unit price for trial 𝑗 ($/veh-km)
𝐸𝐸𝐶𝑗,𝑘= environmental and external cost unit price for the vehicle type 𝑘 for
trial 𝑗 ($/veh-km)
𝑘 = vehicle type, 𝑘 ∈ (𝐿𝑉,𝐻𝑉)
𝑃(𝑘)𝑗 = proportion of vehicle type 𝑘 for trial 𝑗 (%)
𝑉𝐻𝑇𝑆𝑗 = vehicle hours travelled saved by using the road for trial 𝑗 (h)
𝑉𝐾𝑇𝑆𝑗 = vehicle kilometre travelled saved by using the road for trial 𝑗 (km)
A discount rate was applied to all future annualised values of monetised benefits
and costs to accommodate the depreciation of the value of money. A BCR of
monetised and discounted impacts can be calculated for Monte Carlo trial 𝑗 as follows:
𝐵𝐶𝑅𝑗 =∑ [𝐵𝑗,𝑦(1 + 𝑑)
−𝑦]𝑛𝑦=0 + 𝑅𝑉𝑗(1 + 𝑑)
−𝑛
𝐶𝑎𝑝𝑗 + 𝑂&𝑀𝑗
(5.2)
Where:
𝑛 = period of planning horizon (years)
𝑑 = discount rate applicable to the project format (%)
𝑦 = corresponding year, 𝑦(0, 1, … , 𝑛)
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 63
𝑅𝑉𝑗 = residual value of the road for trial 𝑗 ($)
𝑂&𝑀𝑗= total O&M cost over the whole planning horizon for trial 𝑗 ($)
5.2 PROBABILITY DISTRIBUTIONS USED IN THIS STUDY
The Monte Carlo simulation requires a careful selection of the form of probability
distribution chosen for each impact, along with nuanced postulation of the distribution
parameters. The distribution for an input variable must be selected with sound
reasoning. Investigating the impacts of applying alternative forms of probability
distribution by variable is beyond the scope of this study. Salling (2008) further
discusses the use of various probability distributions. Coefficient of variable (CV)
needs to be carefully defined as it is a measure of the level of risk in the variable. The
magnitude of risks of various variables have been reviewed previously (Salling &
Leleur, 2011) so are not readdressed here. It is important to note that CV does not
indicate the variety of the variable. For instance, the CV of vehicle hours travelled
saving (VHTS) does not reflect how VHTS may vary between peak-time and off-peak
time. The mean needs to be carefully defined as it indicates the expected value. The
characteristics, including the form of probability distribution, its mean and CV,
predefine the risk of each variable. Therefore, the risks of input variables are inherent
within the risk profile of the outcome Benefit-Cost Ratio (BCR) distribution.
5.2.1 Capital Cost of a Toll Road Project
It is reasonable that a threshold capital cost exists, below which a project’s
development would not be possible, but that higher cost is plausible due to risks. For
this purpose the Cowan’s M3 distribution (Cowan, 1975) was applied. This
dichotomised distribution contains a set proportion of values equal to the minimum,
and the remaining proportion distributed negative-exponentially. It has been
incorporated previously in various transport applications (Bunker & Troutbeck, 2003;
Troutbeck, 1992). Capital cost can be modelled using the Cowan’s M3 distribution in
cumulative form by:
𝐹(𝐶𝑎𝑝𝑗) =
{
1 − 𝜙𝑒− 𝜙(𝐶𝑎𝑝𝑗−𝐶𝑎𝑝𝑚𝑖𝑛)
(𝐶𝑎𝑝𝑎𝑣−𝐶𝑎𝑝𝑚𝑖𝑛) 𝐶𝑎𝑝𝑗 > 𝐶𝑎𝑝𝑚𝑖𝑛1 − 𝜙 𝐶𝑎𝑝𝑗 = 𝐶𝑎𝑝𝑚𝑖𝑛0 𝐶𝑎𝑝𝑗 < 𝐶𝑎𝑝𝑚𝑖𝑛
(5.3)
64 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
Where:
𝐶𝑎𝑝𝑗 = capital cost in present value for trial 𝑗 ($)
𝜙 = probability that capital cost exceeds 𝐶𝑎𝑝𝑚𝑖𝑛 (%)
𝐶𝑎𝑝𝑚𝑖𝑛 = minimum feasible capital cost ($)
𝐶𝑎𝑝𝑎𝑣 = expected capital cost ($)
5.2.2 Case Dependent Input Variables
There is a scarcity with regard to identifying the forms of probability distributions of
various traffic modelling outputs. In the Salling and Leleur’s methodology (2011), a
probability distribution was applied to travel time saving as a whole and each risk of
input variables needed to determine the travel time saving was not modelled in their
study. For the purpose of this study, the normal distribution and the CV of 10 percent
were applied to those input variables, because the normal distribution can be used to
describe uncertain variables (Mun, 2010). Table 5.1 summarises the characteristics of
the probability distributions used for annual average daily traffic (AADT), yearly
traffic growth rate, proportion of heavy vehicle (HV%), vehicle kilometres travelled
saving (VKTS) and VHTS in this study.
Table 5.1 Probability distribution forms and coefficient of variable (CV) of the case depend input
variables
Variable Source Probability
distribution form CV
Annual average daily traffic (AADT) NA Normal distribution 10 %
Traffic growth NA Normal distribution 10 %
Proportion of heavy vehicles (HV%) NA Normal distribution 10 %
Vehicle kilometres travelled saving (VKTS) NA Normal distribution 10 %
Vehicle hours travelled saving (VHTS) Salling and
Leleur (2011)
Normal distribution 20 %
5.2.3 Transport Cost Unit Price
A range of literature was reviewed to determine the probability distributions of unit
prices of travel time, vehicle operating cost (VOC), crash cost (CC), and
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 65
environmental and external cost (EEC). The EEC includes air pollution, greenhouse
gas, noise, water, nature and landscape, urban separation, and upstream and
downstream impacts. Table 5.2 summarises the probability distributions used in this
study for these unit prices. The probability distribution of EEC unit price is not well
studied. As EEC includes variety of impacts, its unit price tends to contain a large risk.
This is similar to CC unit price. Salling and Leleur (2011) used the uniform distribution
for CC unit price. The same distribution was also applied to the EEC unit price in this
study.
Table 5.2 Probability distribution forms and coefficient of variable (CV) of transport cost unit prices
Variable Source Distribution
form
Coefficient of
variation (CV)
Travel time unit price Hensher (2001) Normal
distribution
33 %
Vehicle operating cost (VOC) unit
price
Berthelot et al.
(1996)
Normal
distribution
15 %
Crash cost (CC) unit price Salling and
Leleur (2011)
Uniform
distribution
10 %
Environmental and external cost
(EEC) unit price
NA Uniform
distribution
10 %
5.3 SYNTHESISING A TOLL TUNNEL PROJECT CASE
The overarching characteristics of recently built toll tunnel projects in Brisbane,
Australia were incorporated to synthesise a toll tunnel project case for the purpose of
demonstrating the analysis of risks within Cost-Benefit Analysis (CBA). Toll tunnels
in Brisbane were reviewed, because toll tunnels in Brisbane have all been opened in a
short span of time between 2010 and 2015, as shown in Table 5.3. They are all located
close to each other in Brisbane City and represent overarching characteristics of recent
Australian toll tunnel projects. The project parameters that are needed to conduct CBA
for this type of major road project include; capital cost, annual average daily traffic
(AADT), traffic growth, proportion of heavy vehicles (HV%), vehicle kilometres
travelled saving (VKTS), vehicle hours travelled saving (VHTS), various transport
66 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
costs, operation and maintenance (O&M) cost, planning horizon and discount rate.
Table 5.3 presents these values for Brisbane’s recent urban toll tunnel facilities of
Legacy Way, Clem Jones Tunnel and Airport Link. The amount of capital cost depends
on the size and the type of the infrastructure. For instance, the construction cost of a
tunnel project is usually relatively high. The capital cost of Airport Link was
significantly high, given the fact that its construction was combined with two other
projects, the Northern Busway and the Airport Roundabout Upgrade
(BrisConnections, 2011).
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 67
Table 5.3 Characteristics of Brisbane toll tunnels
Characteristic Legacy Way Clem Jones Tunnel Airport Link
Opening year 2015 (Transurban,
2016d)
2010 (Transurban,
2015b)
2012 (Transurban,
2016b)
Capital cost AU$ 1.5 billion
(ACCIONA Australia,
2015)
AU$ 3 billion (Go
VIA, 2015)
AU$ 5.6 billion
(BrisConnections,
2011)
Annual average
daily traffic
(AADT)
18,000 (2016 estimate)
(Morgans Financial,
2016)
27,000 (2015 actual)
(Morgans Financial,
2016)
30,757 (2012 actual)
(BrisConnections,
2012)
Proportion of
heavy vehicles
(HV%)
Unknown 17 % (Transurban,
2014)
Unknown
Vehicle
kilometres
travelled saving
(VKTS)
(Google, 2016)
0.7 km 1.2 km 1.0 km
Vehicle hours
travelled saving
(VHTS)
Between 3 and 18
minutes depending on
the time of the day
(Google, 2016)
Between 8 and 17
minutes depending on
the time of the day (Go
VIA, 2016)
Between 10 and 14
minutes depending on
the time of the day
(Google, 2016)
Planning
horizon
40 years (SKM &
Connell Wagner, 2008)
Unknown 45 years (SKM &
Connell Wagner, 2006)
Discount rate 6.0 % (SKM & Connell
Wagner, 2008)
Unknown 6.8 % (SKM & Connell
Wagner, 2006)
Table 5.4 summarises the assumptions that were made in order to conduct CBA
of the synthesised case. According to the Australian Bureau of Infrastructure Transport
and Regional Economics (2012), traffic in Queensland, Australia, was estimated to
grow by 2.8 percent annually until 2020. In Queensland, Australia, the discount rate
that was used to evaluate major road projects varies between 6.0 and 7.6 percent
(Connell Wagner, 2004; GHD, 2013; Queensland Government, 2008; SKM & Connell
68 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
Wagner, 2006, 2008). All prices were converted to 2015 Australian dollar values using
the Reserve Bank of Australia’s method (Reserve Bank of Australia, 2017).
Table 5.4 Assumptions made in Cost-Benefit Analysis (CBA) calculation of the synthesised toll
tunnel project case
Item Assumption and the expected value
Capital cost Cowan’s M3 distribution with 𝐶𝑎𝑝𝑚𝑖𝑛 = AU$ 1.4 billion and
probability of actual cost being greater than the minimum, 𝜙
= 63 %, while maintaining an expected value of AU$ 1.5
billion and a CV of 10 %.
AADT at year 1 30,000
Yearly traffic growth in
percentage
2.8 %, the same rate as traffic growth rate in Queensland,
Australia
HV% 10 %
VKTS 1.0 km
VHTS 15 min (0.25 h)
Type of project A toll tunnel project in the greater South East Queensland
region, Australia.
Age of facility A newly constructed facility that has never been used before
opening.
The expected economic life
of a tunnel
100 years (Australian Transport Council, 2006b)
Facility type Acts as part of the motorway (freeway) network in Brisbane,
Australia and is connected to other major roads.
Residual value (RV) The value of an asset is assumed to depreciate linearly over its
expected economic life.
Opening year Opening year is assumed to be year 1 and therefore daily
traffic volume of the first year is equal to AADT before
applying any growth. Traffic volume will then be increased
yearly with the traffic growth rate defined.
User benefits User benefits will be accrued from year 1.
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 69
Item Assumption and the expected value
Capital cost and, operation
and maintenance (O&M) cost
values
Total cost of the whole of planning horizon in present value.
Capital cost was applied as a lump sum at year 1. O&M cost
was distributed equally over the planning horizon. The
proportions of O&M and capital cost are 10 % and 90 %
respectively over the whole planning horizon.
Maximum AADT Absolute maximum AADT for four lane tunnel is 100,000
(based upon 2,250 pc/h/ln according to the Highway Capacity
Manual (Transportation Research Board, 2010) with two
lanes per direction, peak hour directional split of 55 %, peak
hour to daily ratio of 12 %).
Planning horizon 50 years
Discount rate 7.0 %
5.4 UNIT PRICE OF TRANSPORT COST
Unit prices of travel time, vehicle operating cost (VOC), crash cost (CC), and
environmental and external cost (EEC) are used to monetise transport cost savings.
Table 5.5 summarises the expected values of each unit price, which were determined
on the basis of Austroads guidelines (Tan et al., 2012). All prices were converted to
2015 Australian dollar values using the Reserve Bank of Australia’s method (Reserve
Bank of Australia, 2017). Crash cost of AU$ 0.025 per km was incorporated for both
light vehicles (LV) and heavy vehicles (HV). EEC includes air pollution, greenhouse
gas, noise, water, nature and landscape, urban separation, and upstream and
downstream costs.
70 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
Table 5.5 Transport cost unit price summary (Tan et al., 2012)
Transport cost
unit price
Light vehicles
(LV)
Heavy
vehicles (HV) Note
Travel time (/h) AU$ 22.42 AU$ 56.66 Includes freight travel time.
Proportion of private and business
car uses was obtained from
Australian Bureau of Statistics
(Australian Bureau of Statistics,
2015).
Vehicle operating
cost (VOC) (/km)
AU$ 0.69 AU$ 2.50 VOC for the operating speed of 80
km/h (50 mi/h).
Proportions of cars, light
commercial vehicle and heavy
vehicle were obtained from
Australian Bureau of Statistics
(Australian Bureau of Statistics,
2015).
Crash cost (CC)
(/km)
AU$ 0.025 for both LV and HV
Environmental and
external cost (EEC)
(/km)
AU$ 0.14 AU$ 1.02 Proportions of cars, light
commercial vehicle and heavy
vehicle were obtained from
Australian Bureau of Statistics
(Australian Bureau of Statistics,
2015).
5.5 RESULTS AND DATA SYNTHESIS
Table 5.6 summarises the calculation of deterministic impacts of the synthesised case
when all variables were equal to the expected values of their stochastic distributions.
The benefit that most contributed to the overall benefit was the travel time saving,
which is impacted by the risks of annual average daily traffic (AADT), traffic growth,
travel time unit price and vehicle hours travelled saving (VHTS).
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 71
Table 5.6 Impacts of the synthesised toll tunnel case when all variables were deterministically equal to
their expected values in present value
Project impact Amount Proportion
Travel time saving AU$ 1,553,975,403 83.9 %
Vehicle operating cost (VOC) saving AU$ 209,578,588 11.3 %
Crash cost (CC) saving AU$ 5,927,046 0.3 %
Environmental and external cost (EEC) saving AU$ 55,623,491 3.0 %
RV AU$ 27,243,077 1.5 %
Total saving of transport costs AU$ 1,852,347,605 -
Capital cost AU$ 1,500,000,000 90.9 %
Operation and maintenance (O&M) cost AU$ 150,000,000 9.1 %
Total cost AU$ 1,650,000,000 -
Net present value AU$ 202,347,605 -
BCR 1.12 -
For the purpose of determining impacts of each risk, Benefit-Cost Ratio (BCR)
distributions were calculated individually, using a combination of deterministic
variables and stochastic variables. Table 5.7 summarises by row the statistical
measures of risk profile identified previously, as each input variable was varied
according to its defined distribution, while in each case holding all other variables at
their expected value. Note that the bottom row reflects these measures when all input
variables were varied according to their defined distributions.
72 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
Table 5.7 Risk profiles of output Benefit-Cost Ratio (BCR) distribution as input variable was
distributed stochastically
All variables held to
expected value aside from: Mean Median CV Skew
Probability of
BCR above 1.0
Capital cost 1.13 1.17 8 % -1.61 90 %
AADT 1.12 1.12 10 % -0.02 88 %
Traffic growth 1.12 1.12 4 % 0.09 100 %
HV% 1.12 1.12 1 % 0.01 100 %
Travel time unit price 1.12 1.12 28 % 0.02 66 %
VOC unit price 1.12 1.12 2 % 0.00 100 %
CC unit price 1.12 1.12 <0 % 0.00 100 %
EEC unit price 1.12 1.12 <0 % 0.00 100 %
VKTS 1.12 1.12 1 % 0.00 100 %
VHTS 1.12 1.12 17 % 0.00 75 %
All 1.13 1.09 36 % 0.61 60 %
When each non-skewed distribution was applied alone, the mean value of the
BCR distribution was found to equal the deterministic BCR of 1.12. However, when
capital cost distribution, which is a skewed Cowan’s M3 model, was applied alone, the
mean value of the BCR value was found to be slightly higher at 1.13. This is correct,
as point BCR is mathematically biased under a ratio distribution containing a skewed
distribution. When all distributions were applied, the mean value of the BCR
distribution was also found to equal 1.13, due to the presence of the skewed capital
cost distribution.
The skew of the BCR distribution of capital cost was noticeably negative due to
the application of Cowan’s M3 distribution. When travel time unit price contains a
high risk, or all variables contain risks, the probability of BCR above 1.0 was
noticeably lower. This indicates that although when mean BCR is higher than 1.0, the
risk can be considerably high when these risks exist. When risks of all input variables
were incorporated, the outcome BCR distribution was slightly skewed.
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 73
Figure 5.1 illustrates box plots of BCR distributions with each variable varied
stochastically, and all variables varied stochastically. Medians vary due to the
skewness of the capital cost distribution as discussed above. Coefficient of variation
(CV) noticeably affected the outcome BCR distribution for the following variables in
order of influence; travel time unit price, VHTS, AADT, capital cost, and traffic
growth. CV minimally affected the outcome BCR distribution for the following
variables in order of influence; vehicle operating cost (VOC), proportion of heavy
vehicle (HV%), vehicle kilometres travelled saving (VKTS), environmental and
external cost (EEC), and crash cost (CC). When risks of all input variables were
incorporated, CV was significantly high, which indicates the high risk associated with
the synthesised case.
Figure 5.1 Box-and-whisker plots of Benefit-Cost Ratio (BCR) with each variable varied
stochastically, and all variables varied stochastically
74 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
It is apparent from Table 5.7 and Figure 5.1 that, when risks of all input variables
are incorporated into the stochastic analysis, there is considerable spread in the
outcome BCR distribution, and therefore considerable risk exists within the case to
proceed. In fact, there is only a 60 percent chance that the synthesised case would
achieve a net positive impact to the community. Additionally, there are many possible
combinations of input variables that would lead to the project delivering a very poor
BCR. Given the scale of such a project, the results of this analysis demonstrate that it
would be unwise not to undertake stochastic analysis within Cost-Benefit Analysis
(CBA), or detailed multi-way sensitivity analysis at a minimum, to assist in decision
making.
5.6 DISCUSSION
Salling and Leleur (2011) introduced an innovative methodology by combining Cost-
Benefit Analysis (CBA) and the Monte Carlo simulation. In comparison, this study
stochastically modelled a wider variety of input variables of CBA, which allowed the
different characteristics of each variable to be portrayed. Moreover, this study
examined the impacts of each source of risk on the analysis outcome.
Although, Asplund and Eliasson (2016) claim that transport investment and
transport demand risks affect the CBA results the most, the results showed that the
risks of travel time unit price, VHTS, and traffic growth, as well as AADT and capital
cost affected the outcome BCR the most. This is a consistent finding with the finding
that the travel time savings most contributed in the overall benefits.
Capital cost significantly impacts overall cost of the project. This indicates that
when the host government is not responsible for capital cost, such as build-operate-
transfer (BOT) and design-build-finance-operate (DBFO) schemes, a high overall
Benefit-Cost Ratio (BCR) can result. Complex inter-relationship of the length of
planning horizon, risk-sharing arrangements, discount rates and BCR of a toll road
project is the subject of further investigation.
Travel time saving is a multiplication of annual average daily traffic (AADT),
traffic growth, travel time unit price and vehicle hours travelled saving (VHTS). Each
of these variables has a unique risk that needs to be portrayed in its probability
distribution. When risks are underestimated or ignored in the analysis, interpretations
of the BCR would be limited. Moreover, travel time saving resulted in the highest
Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis 75
benefit. This indicates the importance of conducting sensitivity analysis on all the input
variables that influence the travel time saving, such as AADT and VHTS.
The reliability of the results depends on the reliability of predefined probability
distribution applied for each input variable in the Monte Carlo simulation. Further
study is needed to determine appropriate probability distributions for each variable,
particularly for those with significant impacts on the outcome BCR. For instance, Bain
(Bain, 2009) conducted a study of traffic forecast errors of toll road projects and
identified its probability distribution.
Additionally, it was beyond the scope of this study to consider the correlations
between input variables. For instance, there may be some correlations between VHTS
and vehicle kilometres travelled saving (VKTS). Although the impact of the risk of
VKTS was found to be minimal and the correlation between these two variables may
not be a significant consideration for the purpose of this study, further study to
investigate the correlations of various variables can be useful.
For any Public-Private Partnership projects, the appropriate discount rate needs
to be carefully selected when the project risk is shared. Depending on the risk
allocations, in project evaluation, the systematic risk premium may require adjustment
to reflect the proportion of risks that the public sector is bearing (Australian
Department of Infrastructure and Regional Development, 2013). A lower, risk-free
rate should be used when all of the systematic risks are borne by the private sector
(Australian Department of Infrastructure and Regional Development, 2013). In
practice, the planning horizon is the same as the duration of the toll concession period
of the project. This is because the scope of the evaluation is predefined as the viability
of the project over the whole concession period. Depending on the discount rate
applied, the net impact of the project will depreciate to negligible amounts after a
certain number of years. Discount rate and planning horizon are thus inextricably
linked and require careful consideration.
5.7 SUMMARY
This chapter explored the impacts of risks of each input variable on the analysis
outcome. A synthesised toll tunnel project case was examined, in order to explore
various risk scenarios. The Monte Carlo simulation approach was used in the Cost-
Benefit Analysis (CBA) case to quantify the risks of input variables. The distribution
76 Chapter 5: Incorporating Stochastic Approach in Cost-Benefit Analysis
of a stochastic Benefit-Cost Ratio (BCR) set was analysed to develop a risk profile of
the synthesised case. Risk profiles of the outcome BCR distributions under various
risk scenarios were examined to determine the risk that most impacted the net impact
to the community.
The results showed that the risks of capital cost, annual average daily traffic
(AADT), travel time unit price and vehicle hours travelled saving (VHTS)
significantly impacted the outcome BCR distribution, while the effect of other risks
were minimal. This suggests that these risks need to be properly assessed in project
evaluation of a toll road project. Furthermore, this also suggests strong emphasis on
further research in the fields of transport economics and traffic modelling to reduce
risks of these variables, from the viewpoint of conducting reliable project evaluation.
The proportion of BCR trials greater than 1.0 was shown to be useful in the
decision making, however it may not be as useful when BCR is highly likely to be
greater than 1.0 across all scenarios. The probability corresponding to any BCR value
can be found, which would assist decision-makers based upon their objectives and
policies. Mean and coefficient of variation (CV) provided extremely useful means of
profiling risk using the study approach. Box plots effectively illustrated the
characteristics of each risk, including its spread and skew.
Comprehensive risk profiles of the impacts to the community can be formed by
combining CBA and the Monte Carlo simulation approach. This is particularly useful
to the host government as the decision-maker. Moreover, the methodology is highly
practical and can be incorporated by various practitioners involved in project
evaluation and decision making of public investments. The developed risk profiles are
particularly useful when the project is in the planning phase and risks are substantial.
Chapter 6: Evaluating a Toll Tunnel Project 77
Chapter 6: Evaluating a Toll Tunnel Project
The private sector is often involved in toll road projects, including various schemes to
design, build, operate and/or finance the project either in a partnership with a host
government, independently, or in some combination. Involvements of the private
sector require careful allocations of project impacts when conducting Cost-Benefit
Analysis (CBA), in order to properly reflect the net impact to the community. The aim
of this chapter is to investigate whether alternative assumptions in CBA are valid from
differing perspectives, when toll roads are delivered and operated privately rather than
by a host government. Treatments of tolls and other toll road project-related payments
are considered from different perspectives. CBA is conducted for the previously
synthesised toll tunnel project case by alternating treatments of some impacts. This
leads to the exploration of CBA outcomes when the treatment of tolls differ when two
perspectives of “toll as a transfer payment” (TT) and “toll as an end-user cost” (TC)
are considered. The Monte Carlo simulation approach is used to account the risks of
various variables in the CBA.
6.1 EXAMINING PERSPECTIVES
6.1.1 Hypothesis
Traditionally, when Cost-Benefit Analysis (CBA) is used to evaluate toll projects, tolls
have been assumed to be, and therefore treated, as financial transfers and not counted
as societal costs; instead the capital cost, and operation and maintenance (O&M) cost
are those which are treated as the societal cost impacts. As Decorla-Souza (2013)
claimed, toll revenues are generally only included in CBA by affecting travel
behaviours and efficiencies in the transport system. This is rational when the host
government obtains the toll revenues, because the end-users who pay those tolls are
constituents of the host government and therefore enjoy the benefit of that toll revenue
through government expenditure, including repayment of project debt. However,
depending on the perspective taken within decision making, the influences of each
impact need to be considered carefully in CBA, especially when the private sector is
involved in the project. This is particularly so for cost impacts that are borne by the
private sector.
78 Chapter 6: Evaluating a Toll Tunnel Project
If one takes the perspective that the private operator is an element of an overall
economy that bears the costs and reaps the benefit of a project, then the assumption of
the toll as a transfer payment is appropriate. However, for public sector decision
making, an alternative perspective can be that the host government, as the decision-
maker on behalf of the community, should consider how the end-users bear the cost
and reap the benefit of a project. Under such an assumption, cost impacts are
considered to be recouped in a commercial environment by a private operator charging
tolls to the end-users, who in the case of a toll road, are normally the host government’s
constituents. Therefore, from this perspective, those end-user toll charges should be
counted as the societal cost impacts in CBA. Furthermore, it is reasonable to contend
that any capital and/or O&M costs that are borne by the private operator should be
excluded from the CBA, because they are financial impositions that are contained
within the private operator’s enterprise of offering services to consumers, rather than
as an end-user societal cost. The effect of this perspective is that the private operator
is sequestered from the overall economy, such that the host government can evaluate
the project independent of the private operator’s financial interests. Notwithstanding,
these considerations become more entangled when a toll road project is delivered in
some form of Public-Private Partnership (PPP).
The principal rationale of the “toll as an end-user cost” (TC) perspective is that
it may enable the public decision-maker to understand how the risk profile to the end-
user community as expressed by the CBA might differ from that of the risk profile
among the overall economy, including the toll operator, under the “toll as a transfer
payment” (TT) perspective. The remainder of this chapter uses a case-study approach
to examine the extent to which CBA results vary between these two perspectives.
6.1.2 Consideration of Cost Formats of Toll Road Projects
Commonly for a toll road project, concession deeds may include various risk-sharing
arrangements. For instance, a minimum revenue guarantee arrangement enables the
private operator to mitigate its traffic uncertainty risk with its financial obligations,
through a mechanism where the host government effectively acts as a guarantor should
revenue fall short of the private operator’s required debt repayment during a period.
Alternatively, the host government may permit the private operator to charge a higher
toll price, in order to balance its traffic uncertainty risk with its financial obligation of
debt repayment. Additionally, an upfront capital cost contribution may be paid by the
Chapter 6: Evaluating a Toll Tunnel Project 79
host government to support the start-up of the project; the amount depending upon its
budgetary and political priorities. These arrangements are forms of risk management
strategy and need to be considered carefully in project evaluation. Therefore, the CBA
for the purpose of evaluation of toll road projects needs to appropriately account for
these impacts and their risks.
Figure 6.1 summarises the payment movement when a toll road project is fully
delivered by the host government. When the host government is designing, building,
financing and operating the toll road, including through traditional methods of
purchasing from the private sector, they are responsible for capital cost and O&M cost,
while the road users, who are its constituents, are paying for tolls. In this scenario, the
tolls and any imposed consumption taxation can be considered as a financial transfer
between the public toll operator and the users. Moreover, a part of the tolls paid by
commercial vehicles can be considered as financial transfers as they are paid back by
the end-users. However, these are considered as part of the wider economic impacts
and not considered in this study, as with other wider economic impacts that are
generally excluded from the CBA of major road projects.
Figure 6.1 Payment movement of when toll roads are delivered and operated by the host government
from the “toll as a transfer payment” (TT) perspective
Figure 6.2 summarises the payment movement when a toll road is fully designed,
built, financed and operated by a private sector entity or entities. For purposes of this
study, the private sector entities are collectively termed as the private operator. The
host government may be responsible for an upfront capital cost contribution and
minimum revenue guarantee if included in the concession deed. The private operator
is responsible for the balance of capital cost and O&M cost, while collecting tolls and
receiving any minimum revenue guarantee payments from the host government. In this
scenario, tolls are hypothesised to no longer be a financial transfer under the TC
80 Chapter 6: Evaluating a Toll Tunnel Project
perspective, because the sum of upfront capital cost contribution and the guarantee
would not be equivalent to the capital and O&M costs. Hence, costs to the community
that need to be accounted in CBA in this scenario are the upfront capital cost
contribution, any minimum revenue guarantees, and the tolls paid as end-users, net of
any imposed consumption taxation.
Figure 6.2 Payment movement of when toll roads are delivered and operated privately from the “toll
as an end-user cost” (TC) perspective
As introduced in the discussion above, another scenario that could apply to a toll
road is that when the private operator charges a premium toll price instead of receiving
a minimum revenue guarantee from the host government. In this scenario, the premium
tolls paid by the users replace the minimum revenue guarantee in CBA. This is
summarised in Figure 6.3.
Chapter 6: Evaluating a Toll Tunnel Project 81
Figure 6.3 Payment movement of when the private operator charges premium tolls from the TC
perspective
Moreover, a number of other risk-sharing arrangements can be found with toll
road projects, which for brevity are not dealt with in this study. The impacts of the
arrangements need to be considered carefully for each project to determine whether
they need to be counted as costs to the community in CBA.
6.1.3 Perspectives Considered for this Study
As has been previously discussed, a toll road project can be delivered under various
schemes. Two perspectives that consider all of the scenarios that were previously
discussed, and highlight the difference in terms of payment movements between the
host government and the private operator, are examined in this study. The first is the
TT perspective, whereby the toll road project is fully delivered and operated by the
host government at a baseline toll price, therefore the total cost to the community is
the sum of capital cost and O&M cost. Then, three scenarios of the TC perspective are
considered. The first scenario is a “baseline toll with no guarantee” (BNG), whereby
the private operator receives no minimum revenue guarantees and charges users the
baseline toll price, which is further detailed in a later section. The second scenario is a
“baseline toll with minimum revenue guarantee” (BRG), whereby the private operator
charges users the baseline toll price, however receives a minimum revenue guarantee
from the host government, where necessary, in a given period. The third scenario is a
“premium toll with no guarantee” (PNG), whereby the private operator charges a
higher toll price than baseline, instead of receiving the minimum revenue guarantee.
Table 6.1 summarises the costs considered in CBA across the perspectives and
scenarios.
82 Chapter 6: Evaluating a Toll Tunnel Project
Table 6.1 Costs to the community that are considered in Cost-Benefit Analysis (CBA) for this study
Perspective Scenario Costs considered
Toll as a transfer payment (TT) Capital and O&M costs
Toll as an end-user
cost (TC)
Baseline toll, no guarantee
(BNG)
Baseline tolls paid by end-users and
upfront capital cost contribution
Baseline toll, minimum
revenue guarantee (BRG)
Guarantee payment, baseline tolls paid by
end-users and upfront capital cost
contribution
Premium toll, no guarantee
(PNG)
Premium tolls paid by end-users and
upfront capital cost contribution
For the purpose of CBA, this study presumes that each CBA was undertaken
before the end of construction of the toll road. Therefore, risks exist in the variables
that are determined from traffic modelling and estimations of project-related costs.
These variables include annual average daily traffic (AADT), traffic growth, vehicle
hours travelled saving (VHTS), vehicle kilometres travelled saving (VKTS),
proportion of heavy vehicles (HV%), capital cost, and O&M cost. The risks of these
variables are accounted in CBA using the Monte Carlo approach, as discussed in the
following section.
6.2 METHODOLOGY
Figure 6.4 presents the methodology of the evaluation of the synthesised toll tunnel
project case. It consists of three phases, which are explained in the following section.
Chapter 6: Evaluating a Toll Tunnel Project 83
Figure 6.4 Methodology of the evaluation of the synthesised toll tunnel project case
6.2.1 Identifying Concession Payments and Costs
The concession payments and costs that are involved in a toll road project need to be
first identified. The movements of these payments and costs can then be examined to
identify the entity that is responsible for each payment and cost. Costs that the host
government and its constituents are responsible for, can be determined on the basis of
the payment movements. The costs that can be considered as financial transfers would
be excluded in this process. Total costs in stochastic forms can be developed using the
Monte Carlo simulation, in order to reflect their risks to be incorporated in the
evaluation. Meanwhile, models can be developed for each payment and cost.
6.2.2 Estimation of Benefit
Input variables of benefits considered in CBA, such as vehicle hours travelled saving
(VHTS), need to be determined based on the characteristics of the toll road. Each
benefit in a stochastic form can then be developed on the basis of probability
distribution forms of input variables using the Monte Carlo simulation, in order to
reflect their risks to be incorporated in the evaluation. The benefits that are generally
considered in CBA of a major road project include travel time saving, vehicle
operating cost saving, crash cost saving, environmental and external cost saving, and
residual value (RV).
84 Chapter 6: Evaluating a Toll Tunnel Project
6.2.3 Evaluation and Decision Making
The stochastic Benefit-Cost Ratio (BCR) distribution can be developed based on the
stochastic costs and benefits. The outcome BCR distributions represent the net impacts
and risks of the project. Moreover, risk profiles can be developed for the toll road
project on the basis of the stochasticity of the outcome BCR distributions.
6.3 MODEL DEVELOPMENT
6.3.1 Traffic Volume and Growth
For purposes of clarity of this study, traffic volume is calculated yearly, based on the
initial annual average daily traffic (AADT) and traffic growth rate. The traffic growth
rate is presumed to be constant over the whole planning horizon. The AADT at year 𝑦
for Monte Carlo trial 𝑗 is given as follows:
𝐴𝐴𝐷𝑇𝑦,𝑗 = 𝐴𝐴𝐷𝑇𝑖,𝑗 × (1 + 𝑔𝑗)(𝑦−1)
(6.1)
Where:
𝐴𝐴𝐷𝑇𝑖,𝑗 = initial average annual daily traffic for Monte Carlo trial 𝑗 (veh)
𝑔𝑗 = traffic growth rate for Monte Carlo trial 𝑗 (%)
𝑦 = corresponding year, 𝑦(0, 1, … , 𝑛)
It is noted that this case study does not expressly consider a ramp-up period,
which often occurs post-opening of a toll road. During the ramp-up period, the traffic
growth rate can be different from, and typically less than, the annual growth rate as the
road matures as a component of the greater road network. However, a ramp-up period
may also be readily incorporated in future research.
6.3.2 Baseline Toll Price
The baseline toll price is determined on the basis of the expected traffic volume, while
the project cost contains risks as the baseline toll price is determined before the
completion of the construction. This study presumes that this baseline toll price would
be incorporated into traffic modelling to estimate AADT, traffic growth, VHTS, VKTS
and HV%, therefore the risks of these variables are not accounted in the baseline toll
price model.
Chapter 6: Evaluating a Toll Tunnel Project 85
The baseline toll price is that which equates the sum of the net capital cost after
upfront capital cost contribution is deducted, and the operating and maintenance
(O&M) cost, to the expected value of all collected tolls when brought to net present
value. It is important to note that this is not a financial analysis and does not ensure
that the private operator will recover its cost and yield a profit during the planning
horizon. Rather, it is that particular toll price which, under the expected opening year
AADT and the expected traffic growth rate, would yield the same project cost to the
community as a public road with the same total capital plus O&M cost. That is, under
the “toll as an end-user cost” (TC) perspective, the present value of its expected cost
would the same as that under the “toll as a transfer payment” (TT) perspective. It is a
starting point for consideration of various payments considered in the scenarios, which
are detailed later. The baseline toll price is calculated as follows:
∑[𝑇𝑃𝑏𝑎𝑠𝑒,𝑗 × 𝐴𝐴𝐷𝑇𝑦,𝑒𝑥𝑝 × 365 × (1 + 𝑑)(1−𝑦)]
𝑛
𝑦=1
= (𝐶𝑎𝑝𝑗 + 𝑂&𝑀𝑗 − 𝑈𝑃)
(6.2)
𝑇𝑃𝑏𝑎𝑠𝑒,𝑗 =(𝐶𝑎𝑝𝑗 + 𝑂&𝑀𝑗 − 𝑈𝑃)
∑ [𝐴𝐴𝐷𝑇𝑦,𝑒𝑥𝑝 × 365 × (1 + 𝑑)(1−𝑦)] 𝑛
𝑦=1
(6.3)
𝑇𝑃𝑏𝑎𝑠𝑒 =∑ (𝑇𝑃𝑏𝑎𝑠𝑒,𝑗) 𝑙𝑗=1
𝑙
(6.4)
Where:
𝑛 = number of years in planning horizon
𝑇𝑃𝑏𝑎𝑠𝑒,𝑗 = baseline toll price for Monte Carlo trial 𝑗 ($)
𝐴𝐴𝐷𝑇𝑦,𝑒𝑥𝑝 = expected AADT with expected traffic growth at year 𝑦 (veh)
𝑑 = discount rate applicable to the project format (%)
𝐶𝑎𝑝𝑗 = total capital cost in present value for Monte Carlo trial 𝑗 ($)
86 Chapter 6: Evaluating a Toll Tunnel Project
𝑂&𝑀𝑗= total O&M cost over the whole planning horizon for Monte Carlo trial
𝑗 as a present year cost ($)
𝑈𝑃 = upfront payment to capital cost ($)
𝑙 = number of Monte Carlo trials
When the host government contributes a set upfront capital cost contribution
towards the gross capital cost, the risk of capital cost is borne by the private operator
through the net capital cost that it contributes after the upfront capital cost contribution
is deducted. This study presumes the upfront capital cost contribution to be
deterministic and one third of the expected capital, and operation and maintenance
(O&M) costs. Notwithstanding, the Cost-Benefit Analysis (CBA) presented here could
be modified to allow for a variable upfront capital cost contribution to be made by the
host government.
As shown in Equation 6.2, the baseline toll price is not influenced by the price
that the toll operator or the host government would charge. Rather, it is an optimal toll
price under the assumptions of this study for the purposes of CBA. Sensitivity analysis
could readily be performed on the impact of different baseline toll prices on the
stochastic Benefit-Cost Ratio (BCR) distribution.
6.3.3 Minimum Revenue Guarantee
For purposes of this case study, the minimum revenue guarantee is defined as a
payment paid by the host government to the private operator in any year of the planning
horizon, when the toll revenue of that year is less than the payment that is required of
the private operator to meet its obligations to its financier. For the illustrative purposes
of this study, these are limited to its principal plus interest repayments. The following
annual finance repayment by the private operator for Monte Carlo trial 𝑗 is assumed:
𝑃𝑎𝑛𝑛𝑢𝑎𝑙,𝑗 =𝑟(𝐶𝑎𝑝𝑗 + 𝑂&𝑀𝑗 − 𝑈𝑃)
1 − (1 + 𝑟)−𝑛
(6.5)
Where:
𝑟 = financier’s interest rate on the private entity’s loan (%)
Chapter 6: Evaluating a Toll Tunnel Project 87
This study presumes the financier’s interest rate on the private entity’s loan as
5.0 %. Under the minimum revenue guarantee scenario, any necessary amount of
guarantee payment is calculated uniquely for each period (year) of a Monte Carlo trial
of traffic volume to incorporate the risk of the guarantee payment and the traffic
uncertainty risk in its CBA. This allows the development of a stochastic distribution
of the guarantee payment. The guarantee payment at year 𝑦 for Monte Carlo trial 𝑗 is
given as follows:
𝐺𝑦,𝑗 = 𝑚𝑖𝑛 {(𝐴𝐴𝐷𝑇𝑦,𝑗 × 365 × 𝑇𝑃𝑏𝑎𝑠𝑒) −
𝑃𝑎𝑛𝑛𝑢𝑎𝑙,𝑗(1 + 𝑖)(𝑦−1)
0
(6.6)
Where:
𝑖 = annual rate of inflation in the economy (%)
This study presumes 1.3 % (Reserve Bank of Australia, 2016) as the annual rate
of inflation in the economy.
6.3.4 Premium Toll
The premium toll price is defined in this study as that which the host government
permits the private operator to charge, such that it is expected to earn sufficient revenue
that a minimum revenue guarantee by the host government is not warranted during any
year of the planning horizon, irrespective of traffic uncertainty risk. In this scenario,
stochastically simulated traffic volumes of each Monte Carlo trial, which were
produced under the minimum revenue guarantee scenario, are unknown, as evaluation
of these two scenarios are conducted independently. However, the expected guarantee
payment amount is known, because it can easily be estimated before the completion
of construction of the road. A number of approaches exist to estimate the expected
guarantee payment. For purposes of this study, the stochastic guarantee payment
distribution that was developed under the minimum revenue guarantee scenario was
implemented as the expected guarantee payment. The price of premium toll is
therefore determined on the basis of the expected guarantee payment amount, while
incorporating the traffic uncertainty risk.
88 Chapter 6: Evaluating a Toll Tunnel Project
It is first necessary to calculate the premium toll coefficient. This is the ratio of
the cost that is borne by both the host government and the private operator, to that
which is borne by the private operator alone, under the minimum revenue guarantee
scenario. The premium toll coefficient for Monte Carlo trial 𝑗 is given as follows:
𝑅𝑗 =𝑇𝑃𝑏𝑎𝑠𝑒∑ [𝐴𝐴𝐷𝑇𝑦,𝑗×365×(1+𝑑)
(1−𝑦)]𝑛𝑦=1 +∑ [𝐺𝑦,𝑒𝑥𝑝×(1+𝑑)
(1−𝑦)]𝑛𝑦=1
𝑇𝑃𝑏𝑎𝑠𝑒 ∑ [𝐴𝐴𝐷𝑇𝑦,𝑗×365×(1+𝑑)(1−𝑦)]𝑛
𝑦=1
(6.7)
Where:
𝐺𝑦,𝑒𝑥𝑝 = expected guarantee payment at year 𝑦 in present value ($)
Using this premium toll coefficient, the premium toll price for Monte Carlo trial
𝑗 that would compensate for the absence of minimum revenue guarantee, is therefore
given as follows:
𝑇𝑃𝑝,𝑗 = 𝑇𝑃𝑏𝑎𝑠𝑒 × 𝑅𝑗 (6.8)
Literature (Poole, 2011) has identified that toll price may influence traffic
volume and growth, as some users may be tolled off as toll price increases. For clarity,
this study does not address this micro-economic behaviour, however, elasticity
between toll price and traffic volume may also be considered in future research.
Further, the premium toll is not necessarily that which the private operator would
wish to charge, or which the host government would regulate as a cap. Rather, it is an
optimal toll price under the assumptions of this study, for the purposes of CBA.
Sensitivity analysis could also readily be performed on the impact of different toll
prices on the stochastic BCR distribution.
6.4 RESULTS
6.4.1 Evaluation and Decision making of the Synthesised Toll Tunnel Project
Case
Table 6.2 summarises the risk profiles of the synthesised case. The perspectives of
“toll as a transfer payment” (TT) and “toll as an end-user cost” (TC), and the scenarios
of “baseline toll with no guarantee” (BNG), “baseline toll with minimum revenue
Chapter 6: Evaluating a Toll Tunnel Project 89
guarantee” (BRG) and “premium toll with no guarantee” (PNG) were considered. All
perspectives and scenarios showed similar results of the expected Benefit-Cost Ratio
(BCR) between 1.06 and 1.03. This similarity can be explained by the assumptions
used in the model development in this study. The outcome BCR may differ when
different assumptions are applied. The expected BCR and medians of BCR across
perspectives and scenarios showed great similarities, which indicate that sufficient
Monte Carlo trials were conducted for each scenario. The TT perspective showed the
highest coefficient of variation (CV) and the scenario BNG showed the highest
probability of BCR being greater than 1.0.
Table 6.2 Risk profiles of the synthesised toll tunnel project case across perspectives and scenarios
Perspective Scenario Expected
BCR Median CV
Proportion
of BCR
trials
greater than
1.0
Toll as a transfer payment (TT) 1.06 1.05 21% 59%
Toll as an end-
user cost (TC)
Baseline toll, no guarantee
(BNG)
1.05 1.05 17% 61%
Baseline toll, minimum
revenue guarantee (BRG)
1.03 1.03 18% 57%
Premium toll, no guarantee
(PNG)
1.03 1.03 17% 57%
Figure 6.5 shows the cumulative stochastic BCR distributions of the synthesised
case. The cumulative graph clearly illustrates the wider spread in the BCR distribution
under the TT perspective.
90 Chapter 6: Evaluating a Toll Tunnel Project
Figure 6.5 Cumulative stochastic Benefit-Cost Ratio (BCR) distributions of the synthesised toll tunnel
project case
Figure 6.6 shows box-and-whisker plots of the stochastic BCR distributions of
the synthesised case. The 9th and 91st percentiles were used as the minimum and the
maximum of the whiskers to effectively highlight the characteristics of each
distribution.
Chapter 6: Evaluating a Toll Tunnel Project 91
Figure 6.6 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll tunnel project
case
6.4.2 Examination of Perspectives
Comparison of the perspectives of TT and TC under the scenario BNG reveals nearly
identical expected values of BCR. However, from the perspective of the TC, the CV
is noticeably lower. This is also evident in Figure 6.5 and Figure 6.6. This indicates
that by sequestering the toll operator from the overall economy, there is less volatility
in BCR, and therefore less risk borne by the remainder of the community. It follows
that the risk represented by the difference in CV is borne by the toll operator.
Comparison of the perspectives of TT and TC under the scenario BRG reveals a
slightly lower expected value of BCR. This is because of the additional payments made
by the host government to guarantee the minimum revenue. Again, from the
perspective of the TC, the CV is noticeably lower. This is also evident in Figure 6.5
and Figure 6.6. This indicates that by sequestering the toll operator from the overall
economy, there is less volatility in BCR, and therefore less risk borne by the remainder
92 Chapter 6: Evaluating a Toll Tunnel Project
of the community. While it follows that the risk represented by the difference in CV is
borne by the toll operator, the minimum revenue guarantee payments to some extent
mitigate the toll operator’s risk. On the other hand, the reduction in the expected BCR
indicates that the project is less attractive to the remainder of the community than if
there were no minimum revenue guarantee.
Comparison of the perspectives of TT and TC under the scenario PNG also
reveals a slightly lower expected value of BCR. This is also because of the higher tolls
paid by the end-users. Again, from the perspective of the TC, the CV is noticeably
lower. This is also evident in Figure 6.5 and Figure 6.6. This indicates that by
sequestering the toll operator from the overall economy, there is less volatility in BCR,
and therefore less risk borne by the remainder of the community. While it follows that
the risk represented by the difference in CV is borne by the toll operator, the premium
toll to some extent mitigates the toll operator’s risk. On the other hand, the reduction
in the expected BCR indicates that the project is less attractive to the remainder of the
community than if there were no premium toll.
6.4.3 Sensitivity Analysis of Variation in Risk Characteristics
The previous chapter found that the impacts of the risks of annual average daily traffic
(AADT), traffic growth rate, capital cost and savings on vehicle hours travelled
(VHTS) on the outcome BCR are considerable. BCR distributions were calculated
individually, using a combination of deterministic variables and each of these variables
treated as stochastic to show the vulnerability across perspectives and scenarios against
the risks of the variables. For instance, a scenario with larger CV than other scenarios
when a particular variable is treated as stochastic indicates that the scenario is more
vulnerable to the risk of the variable.
Table 6.3 summarises risk profiles across perspectives, as each input variable
was varied according to its defined distribution, while in each case holding all other
variables at their expected value. When the AADT and the traffic growth rate variables
were treated as stochastic, the difference of CV between the perspective TT and TC
became more apparent. This indicates that the perspective TT is more vulnerable to
the AADT and the traffic growth risks than other risks. When the capital cost variable
was treated as stochastic, the expected BCR for BRG and PNG scenarios significantly
decreased in comparison to when all variables were treated as stochastic. Scenarios
BNG and PNG showed no spread and this indicates that the capital cost risk does not
Chapter 6: Evaluating a Toll Tunnel Project 93
influence the outcome BCR under these scenarios. When the VHTS variable was
treated as stochastic, again, the expected BCR for BRG and PNG scenarios
significantly decreased in comparison to when all variables were treated as stochastic.
CV across perspectives and scenarios showed equal values when the VHTS variables
was treated as stochastic.
Table 6.3 Risk profiles of the synthesised toll tunnel project case across perspectives and scenarios
when each variable was treated as stochastic
Stochastic
variable Perspective Scenario
Expected
BCR Median CV
Proportion of BCR
trials greater than
1.0
Annual
average
daily
traffic
(AADT)
and traffic
growth
rate
TT 1.05 1.05 9% 70%
TC BNG 1.05 1.05 3% 92%
BRG 1.04 1.04 4% 82%
PNG 1.04 1.04 3% 87%
Capital
cost
TT 1.06 1.10 8% 80%
TC BNG 1.05 1.05 <0% 100%
BRG 0.93 0.95 5% <0%
PNG 0.92 0.92 <0% <0%
Vehicle
hours
travelled
saving
(VHTS)
TT 1.05 1.05 17% 62%
TC BNG 1.05 1.05 17% 62%
BRG 0.92 0.92 17% 32%
PNG 0.92 0.92 17% 32%
Figure 6.7 to Figure 6.12 show the cumulative stochastic BCR distributions, and
box-and-whisker plots of the synthesised case when each variable is treated as
stochastic. The 9th and 91st percentiles were used as the minimum and the maximum
of the whiskers to effectively highlight the characteristics of each distribution. The
cumulative graph and the box-and-whisker plots clearly illustrate the wider spread in
94 Chapter 6: Evaluating a Toll Tunnel Project
the BCR distribution under the TT perspective. The perspective TT and the scenario
BNG showed the same distribution characteristics when VHTS is treated as stochastic.
Scenarios BRG and PNG showed the same distribution characteristics that are
different from the perspective TT and the scenario BNG when VHTS is treated as
stochastic.
Figure 6.7 Cumulative stochastic Benefit-Cost Ratio (BCR) distributions of the synthesised toll tunnel
project case when the annual average daily traffic (AADT) and the traffic growth rate variables are
treated as stochastic
Figure 6.8 shows larger CV under the TT perspective. This indicates that the TT
perspective is most vulnerable compared to the TC perspective, when AADT and
traffic growth rate contain risks.
Chapter 6: Evaluating a Toll Tunnel Project 95
Figure 6.8 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll tunnel project
case when the AADT and the traffic growth rate variables are treated as stochastic
Figure 6.9 Cumulative stochastic BCR distributions of the synthesised toll tunnel project case when
capital cost variable is treated as stochastic
96 Chapter 6: Evaluating a Toll Tunnel Project
Figure 6.10 shows large CV under the TT perspective and minimal CV under
the BNG and PNG scenarios. This indicates that the TT perspective is most vulnerable
compared to the TC perspective, when capital cost contains risks. Additionally, the
BNG and PNG scenarios are insensitive to the capital cost risks.
Figure 6.10 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll tunnel
project case when capital cost variable is treated as stochastic
Chapter 6: Evaluating a Toll Tunnel Project 97
Figure 6.11 Cumulative stochastic BCR distributions of the synthesised toll tunnel project case when
vehicle hours travelled saving (VHTS) variable is treated as stochastic
Figure 6.12 shows equivalent sizes of CV under all perspectives and scenarios.
This indicates that the VHTS risks influence the outcomes across all perspectives and
scenarios.
98 Chapter 6: Evaluating a Toll Tunnel Project
Figure 6.12 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll tunnel
project case when VHTS variable is treated as stochastic
The TT perspective resulted in high CV across all variables tested. This indicates
that the TT perspective is vulnerable to AADT, traffic growth rate, capital cost and
VHTS risks. While, CV varied across all variables tested under the TC perspective.
This indicates that the outcome risk profile varies depending on the sources of the risks
that the project contains.
6.5 DISCUSSION
The results suggested that treating tolls as an end-user cost in Cost-Benefit Analysis
(CBA) of a privately operated toll road project is a reasonable and valid approach
under the “toll as an end-user cost” (TC) perspective. Notwithstanding this, the
treatment of other payments of the toll road project need to be considered carefully.
When a toll road project is fully delivered by the host government, the public is
bearing the whole project risk. In contrast, when a toll road project is designed, built,
operated and/or financed by a private operator, a part of risks is shifted to the private
operator. When evaluating a toll road project with respect to a public good, the impacts
and their risks that are borne by the host government on behalf of its constituents
should be considered in the evaluation. In this regard, the risk that is borne by the
Chapter 6: Evaluating a Toll Tunnel Project 99
private operator can effectively be sequestered from the evaluation under the TC
perspective. Therefore, the evaluation of a privately operated toll road project can
reflect this shift of the risk between the host government and the private operator under
the TC perspective.
Risk profiles of “toll as a financial transfer” (TT) and TC perspectives
appropriately reflected the shift of risk in two scenarios. Coefficient of variation (CV)
was lowered in the TC risk profile, which indicates the shift of the risk.
Due to the assumptions applied in the models used in this study, the risk profiles
of three scenarios of TC perspective did not show significant variations with respect
to the risk. Applications of various assumptions, in order to model toll road project
specific payments would further extend the knowledge in terms of how the risk varies
with each assumption.
The synthesised case was found to benefit the community between 57% and 61%
of trials, depending on perspectives and scenarios. The decision-maker may consider
it risky to proceed due to the risk that is quantified, which indicated a reasonably high
probability of BCR being less than 1.0.
The calculated baseline toll price for this synthesised case was $ 4.89. This is
slightly lower than the car toll prices of the existing toll road tunnels in Brisbane,
Australia, the Clem Jones Tunnel and Legacy Way, which are $ 4.93 to $ 4.94,
including goods and services tax (Australian Department of Infrastructure and
Regional Development, 2013). This difference can be explained by the difference
between the theoretical assumptions and the higher complexities of the real toll roads.
The one-way probabilistic sensitivity analysis of variation in risk characteristics
further investigated the vulnerability across perspectives and scenarios towards each
source of risks. The findings of the sensitivity analysis highly rely on the case synthesis
and model assumptions. However, the analysis carried out in this study demonstrated
the methodology to assess the vulnerability of the project.
6.6 SUMMARY
This study examined alternative treatments of tolls and other toll road project-related
payments in Cost-Benefit Analysis (CBA) for a privately operated toll road project
when two perspectives of “toll as a financial transfer” (TT) and “toll as an end-user
100 Chapter 6: Evaluating a Toll Tunnel Project
cost” (TC) were considered. The previously synthesised toll tunnel project case was
evaluated using CBA across various scenarios. In those scenarios, various payments
were considered and their treatments were explored under the two perspectives. The
risk of the synthesised case was quantified by incorporating the Monte Carlo
simulation approach.
Stochastic representations of risk profiles across perspectives and scenarios
illustrated detailed profile, including the sources of risks the most influence the
outcome and the perspectives or scenarios that are most vulnerable to certain risks.
These key considerations related to risks were displayed visually using probability
distribution graphs and box-and-whisker plots. This allowed the results to be easily
interpreted.
This study enhanced the knowledge in terms of the treatment of tolls and other
payments by examining different perspectives in CBA. Furthermore, this study
considered the impacts that are not accounted in financial analysis. This allowed an
exploration of the overall impacts to the community, including transport benefits and
concession payments to the community of a privately operated toll road project.
The assumptions used in this study to develop the models of various payments
can differ between projects in practice. One of the key contributions of the
methodology presented in this study is that it can incorporate various assumptions to
model the payments. Additionally, the risks of input variables, including traffic
forecasts and toll price, can be quantified in the methodology. These risks tend to
reduce towards the opening of the toll road. As has been previously discussed, the risk
that is borne by the host government varies between projects. Various risk-sharing
arrangements and shifts of risk can also be quantified using the methodology. The
quantified risk is one of the key pieces of information that assists in decision making
for a major project. The contributions of this study include the methodology that can
readily be used in practice and are not limited to academic contributions.
The risk of discount rate was not considered in this study. Discount rate depends
on the risk shared between public and private sectors for any Public-Private and
Partnership (PPP) projects. This is because the systematic risk premium is adjusted to
reflect the proportion of risks that the public sector is bearing (Australian Department
of Infrastructure and Regional Development, 2013). The impact of the risk of discount
rate can be explored in the future study. Detailed case studies of existing toll road
Chapter 6: Evaluating a Toll Tunnel Project 101
projects can also be conducted to further explore the impacts of the ramp-up period,
discount rates and various risk-sharing arrangements.
Chapter 7: Evaluating a Toll Road Project 103
Chapter 7: Evaluating a Toll Road Project
This chapter provides an evaluation of a toll road project using Cost-Benefit Analysis
(CBA) for the purposes of comparison and contrast with the findings from previous
chapters. The previous chapters studied a tunnel project case, instead, this chapter
examines an at-grade road project case. A toll road project case is synthesised on the
basis of the overarching characteristics of Australian toll road projects. The
synthesised case is evaluated using the methodologies and the models presented in
Chapter 5 and Chapter 6.
This chapter first summarises the overarching characteristics of Australian toll
road projects, and presents the characteristics of the synthesised case. It then provides
the results of the CBA. The findings are summarised in the final section.
7.1 SYNTHESISING A TOLL ROAD PROJECT CASE
The key difference between an at-grade toll road (termed toll road from hereon) and a
toll tunnel project is the scale of the project. Due to the large construction cost of a
tunnel, the length of the proposed tunnel is often shorter than many other proposed
roads. Therefore, vehicle hours travelled saving (VHTS) and vehicle kilometres
travelled saving (VKTS) of a toll road project can differ from those of a tunnel project.
Table 7.1 summarises the characteristics of three Australian urban toll road
facilities of Hills M2, Logan Motorway and M5 South West. These toll roads were
reviewed, because, first, they are all located in Australian urban area, and second, the
lengths of each road section are all similar, ranging between 21 and 28 kilometres, as
shown in Table 7.1. There are large variations in VKTS between toll roads. This can
be due to the longer length of the roads. VHTS is also noticeably larger than other
tunnels. M5 South West occasionally fails to provide shorter travel distance. This can
be explained by the road network in Sydney, NSW. There are major arterials parallel
to M5 South West that are not tolled, which can provide shorter travel distance
depending on the origin and the destination of an itinerary. However, travel time along
these arterials tends to be significantly higher than M5 South West, which can also
been seen in Table 7.1. This argument suggests that travel time saving depends on the
104 Chapter 7: Evaluating a Toll Road Project
typology of the surrounding transport network and does not necessary depend on the
length of the road.
Table 7.1 Characteristics of Australian toll roads
Characteristic Hills M2 Logan Motorway M5 South West
VKTS (Google,
2016)
Between 0.7 and 1.8
km
Between 5.6 and 6.4
km
Between - 2.7 and 2.3
km (negative shows
that the travel distance
was longer)
VHTS (Google,
2016)
12 minutes depending
on the time of the day
17 minutes depending
on the time of the day
Between 19 and 23
minutes depending on
the time of the day
State VIC QLD NSW
Length 21 km (Transurban,
2016c)
28.9 km (Transurban,
2016e)
22 km (Transurban,
2016f)
Many recent major toll road projects in Australia are tunnel projects. Australian
toll road projects, Hills M2, Logan Motorway and M5 South West all have been built
many years ago and their cost figures do not represent appropriate cost figures for the
synthesis of the case for this study. It is also difficult to gain access to the original
project cost calculations of old road projects. Construction costs of tolled and non-
tolled roads do not particularly differ. Therefore, the costs of West Petrie Bypass
(WPB) were reviewed as a model project. The WPB is not a toll road, however is one
of the recent major road projects in Brisbane, Australia. The business case of the WPB
was developed in 2013 (GHD, 2013) and provides the most recent cost figures. Table
7.2 summarises the project costs of the WPB. All costs are shown with conversion to
2015 dollars for equitable comparison, using the inflation methodology of the Reserve
Bank of Australia (2017).
Chapter 7: Evaluating a Toll Road Project 105
Table 7.2 Project costs of West Petrie Bypass project in 2015 dollars (GHD, 2013)
Cost item Cost
Capital cost AU$ 130,480,078
Operation and maintenance (O&M) cost AU$ 68,000 per year
State QLD
Length 1.9 km
7.2 SYNTHESISED TOLL ROAD PROJECT CASE CHARACTERISTICS
Input variables, including annual average daily traffic (AADT), traffic growth rate,
proportion of heavy vehicles (HV%), unit prices of transport costs, and other
assumptions that are not discussed below are the same as the previously synthesised
toll tunnel project case. Table 7.3 summarises the input variables and the assumptions
that are different from the previously synthesised tunnel case. The synthesised case is
a 25 km toll road. The capital cost was assumed to be AU$ 1.7 billion on the basis of
the capital cost per km of the West Petrie Bypass (WRB). The characteristics of the
synthesised case only represents a typical Australian toll road project that provides
shorter travel time and distance. The projects with unusual characteristics are beyond
the scope of this study.
106 Chapter 7: Evaluating a Toll Road Project
Table 7.3 Assumptions made in Cost-Benefit Analysis (CBA) calculation of the synthesised toll road
project case
Item Assumption and distribution characteristic
VKTS Normal distribution with an expected value of 4.0 km and a
CV of 10 %.
VHTS Normal distribution (Salling & Leleur, 2011) with an
expected value of 15 min = 0.25 h and a CV of 20 % (Salling
& Leleur, 2011).
Type of project A toll road project in the greater South East Queensland
region, Australia.
The expected economic life of
a road
50 years (Australian Transport Council, 2006b)
Capital cost Cowan’s M3 distribution with 𝐶𝑎𝑝𝑚𝑖𝑛 = AU$ 1.58 billion
and probability of actual cost being greater than the
minimum, 𝜙 = 65 %, while maintaining an expected value of
AU$ 1.7 billion and a CV of 10 %. Capital cost was assumed
to be AU$ 69 million per kilometre on the basis of the West
Petrie Bypass project (GHD, 2013).
Proportion of capital cost and
operation and maintenance
(O&M) cost
The proportions of O&M and capital cost are 3 % and 97 %
respectively over the whole planning horizon. This was
assumed on the basis of the O&M cost of AU$ 900,000 per
year. O&M cost per kilometre was assumed to be AU$ 36
million per year on the basis of the West Petrie Bypass
project (GHD, 2013).
Upfront capital cost
contribution
One third of the expected capital, and operation and
maintenance (O&M) costs (AU$ 580 million).
7.3 RESULTS
7.3.1 Evaluation and Decision making of the Synthesised Toll Road Project
Case
Table 7.4 summarises the calculation of the point Benefit-Cost Ratio (BCR) when all
variables were equal to the expected values of their stochastic distributions. The
measure that most contributed to the overall benefit was the travel time saving. It is
noted that this would be impacted by the risks of annual average daily traffic (AADT),
Chapter 7: Evaluating a Toll Road Project 107
traffic growth, travel time unit price, and vehicle hours travelled saving (VHTS). The
resultant BCR was 1.41, which reflects a net positive impact of the synthesised toll
road case.
Table 7.4 Impacts of the synthesised toll road project case when all variables were deterministically
equal to their expected values in present value
Project impact Amount Proportion
Travel time saving AU$ 1,452,313,461 58.9 %
Vehicle operating cost (VOC)
saving
AU$ 783,471,356 31.8 %
Crash cost (CC) saving AU$ $22,157,181 0.9 %
Environmental and external cost
(EEC) saving
AU$ 207,938,285 8.4 %
RV AU$ 0 0 %
Total saving of transport costs AU$ 2,465,880,283 -
Capital cost AU$ 1,700,000,000 97.1 %
Operation and maintenance (O&M)
cost
AU$ 51,000,000 2.9 %
Total cost AU$ 1,751,000,000 -
Net present value AU$ 714,880,283 -
BCR 1.41 -
Table 7.5 summarises the risk profiles of the synthesised case. The perspectives
of “toll as a transfer payment” (TT) and “toll as an end-user cost” (TC), and the
scenarios of “baseline toll with no guarantee” (BNG), “baseline toll with minimum
revenue guarantee” (BRG) and “premium toll with no guarantee” (PNG) were
considered. All perspectives and scenarios showed similar results of the expected
Benefit-Cost Ratio (BCR) between 1.36 and 1.42. This similarity can be explained by
the assumptions used in the model development in this study. The outcome BCR may
differ with the different assumptions used. The expected and medians of BCR across
perspectives and scenarios showed great similarities, which indicated that sufficient
Monte Carlo trials were conducted for each scenario. The TT perspective showed the
108 Chapter 7: Evaluating a Toll Road Project
highest coefficient of variation (CV). All scenarios under the TC perspective resulted
in similarly high proportions of BCR trials greater than 1.0.
Table 7.5 Risk profiles of the synthesised toll road project case across scenarios
Perspective Scenario Expected
BCR Median CV
Proportion of BCR
trials greater than 1.0
Toll as a transfer payment (TT) 1.42 1.41 18% 96%
Toll as an
end-user cost
(TC)
Baseline toll, no
guarantee (BNG)
1.40 1.40 13% 99%
Baseline toll,
minimum revenue
guarantee (BRG)
1.37 1.36 14% 98%
Premium toll, no
guarantee (PNG)
1.36 1.36 13% 99%
Figure 7.1 shows the cumulative stochastic BCR distributions of the synthesised
case. The cumulative graph clearly illustrates the wider spread in the BCR distribution
under the TT perspective.
Chapter 7: Evaluating a Toll Road Project 109
Figure 7.1 Cumulative stochastic Benefit-Cost Ratio (BCR) distributions of the synthesised toll road
project case
Figure 7.2 shows box-and-whisker plots of the stochastic BCR distributions of
the synthesised case. The 9th and 91st percentiles were used as the minimum and the
maximum of the whiskers to effectively highlight the characteristics of each
distribution.
110 Chapter 7: Evaluating a Toll Road Project
Figure 7.2 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll road project
case
7.3.2 Sensitivity Analysis of Variation in Risk Characteristics
Similar to Chapter 6, the impacts of the risks of annual average daily traffic (AADT),
traffic growth rate, capital cost and vehicle hours travelled saving (VHTS) were
investigated. Again, BCR distributions were calculated individually, using a
combination of deterministic variables and each of these variables were treated as
stochastic.
Table 7.6 summarises risk profiles across perspectives, as each input variable
was varied according to its defined distribution, while in each case holding all other
variables at their expected value. When the AADT and the traffic growth rate variables
were treated as stochastic, the difference in CV between scenarios BNG, BRG and C
became apparent, compared to when all variables were treated as stochastic. This
indicates that the scenario BRG is more vulnerable to the AADT and the traffic growth
rate risks than scenarios BNG and PNG. When the capital cost variable was treated as
stochastic, the expected BCR for BRG and PNG scenarios significantly decreased in
comparison to when all variables were treated as stochastic. Scenarios BNG and PNG
showed no spread and this indicates that the capital cost risk does not influence the
Chapter 7: Evaluating a Toll Road Project 111
outcome BCR under these scenarios. When the VHTS variable was treated as
stochastic, again, the expected BCR for BRG and PNG scenarios significantly
decreased in comparison to when all variables were treated as stochastic. The
proportion of BCR trials greater than 1.0 across perspectives and scenarios were
sufficiently high, apart from scenarios BRG and PNG, which indicates the
vulnerability of these scenarios against the VHTS risk.
Table 7.6 Risk profiles of the synthesised toll road project case across scenarios when each variable
was treated as stochastic
Stochastic
variable Perspective Scenario
Expected
BCR Median CV
Proportion of
BCR trials
greater than
1.0
Annual average
daily traffic
(AADT) and
traffic growth
rate
TT 1.41 1.41 10% 100%
TC BNG 1.40 1.41 3% 100%
BRG 1.37 1.38 5% 100%
PNG 1.37 1.38 3% 100%
Capital cost TT 1.42 1.47 9% 100%
TC BNG 1.41 1.41 <0% 100%
BRG 1.20 1.22 5% 99%
PNG 1.19 1.19 <0% 100%
Vehicle travelled
hours saving
(VHTS)
TT 1.41 1.41 12% 100%
TC BNG 1.41 1.41 12% 100%
BRG 1.19 1.19 12% 92%
PNG 1.19 1.19 12% 92%
Figure 7.3 to Figure 7.8 show the cumulative stochastic BCR distributions, and
box-and-whisker plots of the synthesised case when each variable is treated as
stochastic. The 9th and 91st percentiles were used as the minimum and the maximum
of the whiskers to effectively highlight the characteristics of each distribution. The
cumulative graph and the box-and-whisker plots clearly illustrate the wider spread in
the BCR distribution under the TT perspective. The perspective TT and the scenario
112 Chapter 7: Evaluating a Toll Road Project
BNG showed the same distribution characteristics when VHTS is treated as stochastic.
Scenarios BRG and PNG showed the same distribution characteristics that are
different from the perspective TT and the scenario BNG when VHTS is treated as
stochastic.
Figure 7.3 Cumulative stochastic BCR distributions of the synthesised toll road project case when the
annual average daily traffic (AADT) and the traffic growth rate variables are treated as stochastic
Chapter 7: Evaluating a Toll Road Project 113
Figure 7.4 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll road project
case when the AADT and the traffic growth rate variables are treated as stochastic
Figure 7.4 indicates that the TT perspective is most vulnerable to AADT and
traffic growth rate risks compared to the TC perspective. This indicates that a toll road
project is vulnerable to traffic risk the most when it is fully delivered the host
government.
114 Chapter 7: Evaluating a Toll Road Project
Figure 7.5 Cumulative stochastic BCR distributions of the synthesised toll road project case when the
capital cost variable is treated as stochastic
Figure 7.6 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll road project
case when the capital cost variable is treated as stochastic
Chapter 7: Evaluating a Toll Road Project 115
Figure 7.6 showed that the scenarios BNG and BRG resulted in minimal CV
when capital cost risk exists. This indicates that the capital cost risk does not impact
the project outcome when the project is delivered by the private operator and the host
government does not provide the minimum revenue guarantees.
Figure 7.7 Cumulative stochastic BCR distributions of the synthesised toll road project case when the
vehicle hours travelled saving (VHTS) variable is treated as stochastic
116 Chapter 7: Evaluating a Toll Road Project
Figure 7.8 Box-and-whisker plots of stochastic BCR distributions of the synthesised toll road project
case when the VHTS variable is treated as stochastic
Figure 7.8 showed that all perspectives and scenarios resulted in equivalent CV
when vehicle hours travelled saving (VHTS) risk exists. This indicates that the
delivery method does not influence the level of VHTS risk that the host government is
bearing. The TT perspective resulted in higher CV compared to the TC perspective
across all variables tested. While, the CV of the TC perspective varied across all
variables tested. This indicates that the outcome risk profile varies depending on the
sources of risks that the project contains.
7.4 COMPARISON BETWEEN TOLL TUNNEL AND ROAD PROJECTS
7.4.1 A Review of Benefit-Cost Ratio
The synthesised toll road project case resulted in a higher expected Benefit-Cost Ratio
(BCR) than the previously synthesised toll tunnel project case, although the total cost
of the tunnel case was lower. This is due to higher total benefits accrued from larger
vehicle kilometre travelled saving (VKTS). The proportions of travel time saving and
vehicle operating cost saving values also reflected the increase of VKTS. The savings
in crash cost (CC) and environmental and external cost (EEC) were insignificant
similarly to the synthesised toll tunnel project case.
Chapter 7: Evaluating a Toll Road Project 117
7.4.2 A Review of Risk Profiles and Perspectives
An overall increase of Benefit-Cost Ratio (BCR) of the synthesised road case was
observed and this resulted in the higher expected BCR, the higher medians and larger
proportions of BCR trials greater than 1.0 across perspectives and scenarios. For both
of the synthesised tunnel and road cases, the “toll as a transfer payment” (TT)
perspective showed a higher coefficient of variation (CV) than the “toll as an end-user
cost” (TC) perspective. This indicates that the shift of risk was successfully illustrated
in the risk profiles for both cases. An overall CV of the synthesised tunnel case showed
higher values than the overall CV values of the synthesised road case across
perspectives and scenarios. This indicates that the risk of the synthesised road case is
less than the one of the synthesised tunnel case.
7.5 SUMMARY
This chapter detailed the evaluation of a synthesised toll road project for the purposes
of comparison and contrast with the findings of previous chapters. A toll road project
case was synthesised on the basis of the overarching characteristics of existing
Australian major road projects. Previously proposed Cost-Benefit Analysis (CBA) and
the Monte Carlo simulation methodologies were used for the purpose of the evaluation.
Similar to Chapter 6, the perspectives of “toll as a financial transfer” (TT) and “toll as
an end-user cost” (TC) were examined in the evaluation.
This chapter assesses the applicability of the proposed CBA methodology by
directly applying it to the synthesised toll road project case. The results were consistent
with the findings in Chapter 6, which examined the evaluation of the synthesised toll
tunnel case, and indicated that the findings of this study are applicable to both toll road
projects and toll tunnel projects.
The synthesised case resulted in an expected Benefit-Cost Ratio (BCR) of 1.41
and was therefore found to benefit the community. The significant benefits of the
synthesised case were travel time saving and vehicle operating cost saving (VOCS),
which showed proportions of 58.9 % and 31.8 % respectively. The risk profile
measures were found to be useful, however due to the high outcome BCR, the
proportion of BCR trials greater than 1.0 failed to indicate the level of risk across
perspectives and scenarios. Instead, coefficient of variation (CV) effectively
represented the risk of the synthesised case. This indicates that CV and stochastic
118 Chapter 7: Evaluating a Toll Road Project
results better represent the risk profile, especially when the outcome BCR is highly
likely to meet the required cut-off value.
The calculated baseline toll price was $5.21 for the synthesised road case, which
is a little higher than the calculated baseline toll price of the synthesised tunnel case.
This increase is due to the higher capital cost and the higher capital cost contribution
as a result. However, this price is only slightly higher than the existing toll prices in
Brisbane, Australia, which indicates that the baseline toll price model assumptions
used in this study are valid and realistic for both tunnel and road cases.
Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects 119
Chapter 8: Proposed Methodology for
Evaluations of Toll Road
Projects
This chapter proposes the Cost-Benefit Analysis (CBA) methodology for toll road
projects that was developed in this study. A typical project appraisal process that is
commonly used by Australian government bodies is reviewed, then how the proposed
methodology can be implemented in the existing process is discussed. The framework
of the methodology is developed on the basis of the existing CBA methodology that is
documented in the Australian Transport Council’s guideline (Australian Transport
Council, 2006a). Practical considerations are also discussed. Further research that is
needed to refine the methodology is discussed in the final section.
8.1 TYPICAL PROJECT APPRAISAL PROCESS
The project appraisal process can vary greatly between jurisdictions. This study refers
to the project appraisal process that is presented by the Australian Transport Council,
which is a transport authority within the Australian Department of Infrastructure and
Regional Development (Australian Department of Infrastructure and Regional
Development, 2016). Austroads also refers to the Australian Transport Council
Guidelines (Tsolakis, Preski, & Patrick, 2009) and these guidelines can be referred to
as typical Australian practice. Figure 8.1 shows the project appraisal process that is
advised in the Australian Transport Council’s guideline (Australian Transport Council,
2006a). CBA is abbreviated as “BCA” in that guideline. The steps with a dashed box
represent where the proposed methodology can be implemented. The proposed
methodology is suitable as a detailed CBA methodology as it involves numerical risk
assessment, which is not typically needed in the indicative assessment that only
considers main benefits and costs (Australian Transport Council, 2006a).
120 Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects
Figure 8.1 Project appraisal process (Australian Transport Council, 2006a)
Particularly in Queensland, Australia, CBA is included in the phases of
preliminary evaluation and business case development within the project assurance
framework of Queensland Government (Queensland Department of Infrastructure and
Planning, 2009, 2011). Detailed procedures of CBA is documented in the CBA manual
(Queensland Department of Transport and Main Roads, 2011).
8.2 FRAMEWORK OF THE PROPOSED METHODOLOGY
The Australian Transport Council (2006a) provides guidance on Cost-Benefit Analysis
(CBA) methodology for transport projects. Figure 8.2 illustrates the framework of the
proposed CBA for major road projects that was developed in this study on the basis of
Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects 121
the Australian Transport Council’s CBA methodology. The thick lined boxes represent
the steps that are added or changed. This framework complements the framework that
was used in this study previously, which was shown in Figure 6.4.
Figure 8.2 The proposed Cost-Benefit Analysis (CBA) framework for major road projects
First, the initiative is specified and analysis options are defined. Then, the
required data are acquired. For major road project CBA, the required data include
annual average daily traffic (AADT), traffic growth rate, proportion of heavy vehicles
122 Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects
(HV%), vehicle hours travelled saving (VHTS), vehicle kilometres travelled saving
(VKTS) and various transport cost unit prices. Many of these variables can be
determined through traffic modelling and forecasting. Then the risk allocations are
examined, in order to determine the movements of various payments. The risk
allocations need to align with the previously defined analysis options (see Figure 8.2).
The identified payment movements determine how project impacts need to be treated
in the CBA. Probability distributions then can be applied to each input variable. This
can be determined by the traffic modellers, or otherwise the probability distributions
used in this study can be implemented. However, it is more appropriate to implement
the probability distributions that are determined by the modellers for accurate analysis
outcomes. The probability distributions used in this study were selected on the basis
of a number of previous studies, which may not directly be relevant to a particular
project. Stochastic CBA is then conducted on the basis of the probability distributions
applied to input variables and the treatment of project impacts. Through the stochastic
CBA, risk profiles can be developed. Benefit-Cost Ratio (BCR) and coefficient of
variation (CV) represent the net impacts and risks of the project in the risk profiles.
An option with a higher BCR represents more beneficial option to the community than
other options. An option with a lower CV represents the option with less risk that is
borne by the host government than other options.
The key contribution of the proposed methodology is that the CBA outcome
represents the impacts to the community. This is particularly useful to evaluate a
project solely from the public perspective. The host government acts as the decision-
maker in the project appraisal of major road projects and the decision needs to be made
based on the impacts to the community.
8.3 PRACTICAL CONSIDERATIONS
8.3.1 Conducting the Analysis
The required numerical calculations for the proposed methodology can be conducted
easily using a spreadsheet platform, such as Microsoft Excel, which was used for the
purpose of this study. A spreadsheet is capable of incorporating various probability
distributions. This allows a number of the Monte Carlo simulations to be conducted
rapidly. The simulated values can be used in the Cost-Benefit Analysis (CBA)
calculation, which only involves additions and multiplications. Calculation of
Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects 123
concession payments and other financial analysis that may be needed as part of the
CBA calculation can also easily be conducted using a spreadsheet.
Practitioners could use tools other than spreadsheet to conduct the stochastic
CBA, however their preferred tool needs to be able to simulate or incorporate
stochastic input variables and analyse the stochastic Benefit-Cost Ratio (BCR) for the
purpose of developing risk profiles.
Practitioners may also use other tools to assist with the analysis, such as various
traffic modelling or financial analysis tools. These tools may produce outcomes in
stochastic forms or percentages representing confidence levels. These can be
incorporated into the analysis using a spreadsheet, when practitioners wish to use these
forms.
Additionally, it is important to note that, when software is used to conduct
analyses, every step of the calculations needs to be shown transparently. For instance,
Microsoft Excel has a feature called “macro” or “visual basic for applications (VBA)”
to automate tasks within the Excel workbook. Although VBA is an efficient tool to
simplify the analysis, the practitioner needs to be able to effectively communicate the
analysis outcomes and calculations to the decision-makers when explanations are
needed.
8.3.2 Interpreting the Results
A spreadsheet can be used to present the outcome stochastic BCR using various
measures and graphs. This study used the expected BCR, median, coefficient of
variation (CV), the proportion of BCR trials greater than 1.0, the cumulative
probability distribution graph, and the box-and-whisker plots as the measures to
develop risk profiles. The interpretations of these measures were developed on the
basis of the interpretations of various statistical inferences that are detailed by Mun
(2010).
Table 8.1 summarises the risk profiles that can be developed using the proposed
Cost-Benefit Analysis (CBA) methodology and their interpretations. This summary
can maintain consistencies of interpretations of the analysis outcomes. As has been
highlighted previously, the probability of Benefit-Cost Ratio (BCR) greater than 1.0 is
not an effective measure when all of analysis options are highly likely to result with
BCR greater than 1.0.
124 Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects
Table 8.1 Interpretations of the risk profiles in the proposed methodology
Measure Outcome Interpretation
Expected Benefit-Cost
Ratio (BCR)
Below 1.0 Not economically viable, on average
Greater than 1.0 Economically viable, on average
Higher than other
options
More beneficial to the community than
other options
Lower than other
options
More costly to the community than other
options
Median Similar to the
expected BCR
A sufficient number of Monte Carlo trials
have been conducted
Varies from the
expected BCR
An insufficient number of Monte Carlo
trials have been conducted
Coefficient of variation
(CV)
Higher than other
options
The option involves greater risk than other
options
Lower than other
options
The option involves less risk than other
options
Proportion of BCR trials
greater than 1.0
Higher than other
options
The option is more likely to benefit the
community than other options
Lower than other
options
The option is less likely to benefit the
community than other options
Table 8.2 summarises the interpretation of the cumulative probability
distribution graph, and box-and-whisker plots. These graph and plots are useful tools
to represent the risk profiles visually.
Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects 125
Table 8.2 Interpretations of cumulative probability distribution graphs, and box-and-whisker plots in
the proposed methodology
Item Outcome Interpretation
The cumulative
probability
distribution graph
Wide/flatter Larger coefficient of variation (CV)
therefore the option involves greater
risk than other options
Vertical/steeper Smaller CV therefore the option
involves less risk than other options
Skewed to right compared to
other options
Higher expected Benefit-Cost Ratio
(BCR) than other options therefore
more beneficial to the community
than other options
Skewed to left compared to
other options
Lower expected Benefit-Cost Ratio
(BCR) than other options
Box-and-whisker
plots
Longer box Larger CV therefore the option
involves greater risk than other
options
Shorter box Smaller CV therefore the option
involves less risk than other options
Distance between the top
whisker end and bottom
whisker end is wider than other
options
Larger CV therefore the option
involves greater risk than other
options
Distance between the top
whisker end and bottom
whisker end is narrower than
other options
Smaller CV therefore the option
involves less risk than other options
Centre of box is located higher
than other options
Higher expected BCR than other
options therefore more beneficial to
the community than other options
Centre of box is located lower
than other options
Lower expected BCR than other
options therefore more costly to the
community than other options
126 Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects
8.4 ENHANCEMENT AND REFINEMENT OF THE PROPOSED
METHODOLOGY
As has been discussed in previous chapters, the key issue that needs to be studied
further is about determination of the appropriate forms of probability distributions of
input variables, particularly of those that have not been studied previously. Statistical
studies can be conducted by reviewing past projects, as the available data increases, to
generalise the probability distributions that should be used for each input variable.
However, different types of modelling or estimation techniques can be used between
different projects for the same variable. For instance, there are a number of traffic
forecasting modelling techniques that traffic modellers can use to forecast traffic
demand. The forecasted traffic produced from different techniques can have different
probability distributions depending on the assumptions incorporated in the models
used. This suggests that, when modellers produce the forecasts, they should also be
able to determine the appropriate distribution form for the variables that were
forecasted.
For the input variable with well-established estimation methodology, such as
project cost, previously estimated costs of various projects can be studied statistically
for the purpose of determining the appropriate form of probability distribution. There
are studies found in the literature (Berthelot et al., 1996; Hensher, 2001; Salling &
Leleur, 2011) with regard to appropriate form of probability distribution of some input
variables, which were considered in this study.
8.5 SUGGESTED FUTURE STUDIES
Future studies can be conducted to investigate the impacts of variation in discount rate
on the analysis outcome. Additionally, various concession arrangements and payment
models that were not considered in this study can be studied, using the proposed
methodology. These studies would further extend the knowledge of the CBA of toll
road projects.
Studies can also be conducted on the Cost-Benefit Analysis (CBA) of other types
of transport infrastructure projects, while considering the perspectives and payment
movements. For instance, many public transport projects are often delivered through
a form of Public-Private Partnership (PPP) scheme (Bonnafous, 2012). Types of
benefits and costs may differ from the benefits and costs of a major road project,
Chapter 8: Proposed Methodology for Evaluations of Toll Road Projects 127
however, considering the perspectives in the CBA of public transport projects would
further extend the knowledge of CBA. Similar studies can also be conducted for other
types of PPP projects intended for the public good, such as hospital projects and other
larger health care initiatives, social welfare initiatives, knowledge precinct projects
and the like.
8.6 SUMMARY
This chapter discussed how the proposed methodology can be incorporated in the
existing Australian project appraisal process. Well-regarded guideline was reviewed
to determine the phase in which the proposed methodology can be used. The
framework of the proposed methodology was presented, which was developed on the
basis of the existing Cost-Benefit Analysis methodology. Practical considerations
included how the analysis can be conducted and how the analysis outcomes can be
interpreted. The analysis can be conducted by using a spreadsheet platform such as
Microsoft Excel, however modelling and estimations of input variables may need to
be conducted using various other tools. This chapter also summarised appropriate
interpretations of risk profiles, in order to maintain the interpretations of the analysis
consistent. The issues that need to be further studied were then discussed. Further study
to determine the appropriate forms of probability distributions of input variables,
particularly of those that have not been studied previously, will contribute to
enhancement and refinement of the methodology proposed in this study.
Chapter 9: Conclusion 129
Chapter 9: Conclusion
This chapter first provides a brief summary of the findings of this study. Contributions
to the academic study and practice are then discussed. This is followed by discussion
of the limitations and recommendations of this study. The aim of this study is then
reviewed to examine whether it was achieved and the conclusion of this study is drawn.
9.1 SUMMARY OF FINDINGS
9.1.1 Literature Review
The literature review discussed the key issues of the project evaluation of a toll road
project. It particularly focused on highlighting potential barriers against proper
evaluations and identifying research gaps. Cost-Benefit Analysis (CBA) is the most
commonly used and well-established project evaluation methodology (van Wee &
Rietveld, 2014). The review highlighted limited studies found with regard to CBA of
a toll road project. The representation of risk, using one-way sensitivity analysis in
CBA, is limited by point assumptions of Benefit-Cost Ratio (BCR). Effectively
illustrating risks of a toll road project is particularly important, because toll road
projects can have complex risk characteristics that differ from the risk characteristics
of a general major road project. The risk allocations of a toll road project can also be
unique to each project. This review suggested further examinations of the treatment of
tolls in CBA, because tolls may be collected by the private operator, depending on the
concession arrangement of the project.
9.1.2 A Review of Australian Practice of Cost-Benefit Analysis
Chapter 4 reviewed previously conducted CBA of a number of Australian and UK
major road projects. The review highlighted limitations and difficulties in the CBA
practices, such as time and resource limitations, the complexity of CBA, the level of
comprehensiveness of the CBA that the host government may be expecting, and the
complexity of transport planning. The review also identified a number of technical
inconsistencies, such as the residual value (RV) calculation and the treatment of tolls
in CBA. Further study was suggested to examine the complex mechanisms of risk
allocations, discount rate, and the treatment of tolls in CBA.
130 Chapter 9: Conclusion
9.1.3 Incorporating Stochastic Approach in Cost-Benefit Analysis
Chapter 5 presented the methodology to incorporate the stochastic approach in CBA.
The proposed methodology represents the outcome BCR in a stochastic form, using
the Monte Carlo simulation approach. A toll tunnel project case was synthesised on
the basis of the overarching characteristics of recent toll road projects. The sources of
risks that the most influence the outcome BCR were capital cost, annual average daily
traffic (AADT), travel time unit price, and vehicle hours travelled saving (VHTS). The
risk profile that is developed using the stochastic BCR was found to be extremely
useful in decision making by providing detailed illustration of the project risk.
9.1.4 Evaluating a Toll Tunnel Project
Chapter 6 examined the treatment of tolls and other impacts in CBA of a privately
operated toll road project. Payment movements of various impacts, including tolls and
other concession payments were examined to explore appropriate treatments of the
impacts. Two perspectives of “toll as a financial transfer” (TT) and “toll as an end-
user cost” (TC) were considered in this examination. The previously synthesised toll
tunnel project case was evaluated using the stochastic CBA methodology, in order to
observe shifts of risk across perspectives and scenarios. It was concluded that the
evaluation of the project can reflect the shift of risk between the host government and
the private operator under the TC perspective. The analysis outcomes also suggested
that treating tolls as the cost to the community is a reasonable and valid approach under
the TC perspective.
The expected BCR of the synthesised case was found to be beneficial between
57 % and 61 % of trials, depending on the perspectives and scenarios. The calculated
baseline toll price indicated that the baseline toll price assumption was realistic.
The stochastic CBA illustrated detailed risk profiles across perspectives and
scenarios using. The risk profiles provided insightful CBA outcomes, including the
sources of risks the most influence the outcome and the perspectives or scenarios that
are most vulnerable to certain risks. These key considerations related to risks were
displayed visually, which allowed the results to be easily interpreted.
This evaluation highlighted some of the key contributions of the proposed
methodology. One is the ability to incorporate various assumptions within the model
development. For instance, various financial models can be incorporated within the
Chapter 9: Conclusion 131
baseline toll price model. Different types of concession payments that were not
considered in this study can also be incorporated into the proposed CBA methodology.
Also important is the ability to quantify the risk. Quantifying risks enables comparison
of the risk across perspectives and scenarios. This also allows the shift of risk to be
represented in an empirical manner.
9.1.5 Evaluating a Toll Road Project
Chapter 7 investigated the evaluation of a toll road project, which was synthesised on
the basis of the overarching characteristics of major road projects. Similar to the
previous chapter, the perspectives of TT and TC were considered.
The evaluation resulted in findings consistent with the previous findings. The
shift of risk was observed under the TC perspective for the synthesised case.
Additionally, the analysis outcomes indicated that treating toll as the cost to the
community is a reasonable and valid approach for a privately operated toll road project
under the TC perspective.
The toll road project resulted in a higher BCR due to greater vehicle kilometres
travelled saving (VKTS). Risk profiles across perspectives and scenarios showed that
the coefficient of variation (CV) was useful to observe the level of risk. However, the
proportion of BCR trials greater than 1.0 failed to represent the risk effectively. This
is because the expected BCR across perspectives and scenarios were highly likely to
result in BCR greater than 1.0. The calculated baseline toll price was only slightly
higher than existing toll prices in Australia. This indicates that the baseline toll price
model assumption was also realistic for a road project case, along with a tunnel project
case.
9.1.6 Proposed Methodology
Chapter 8 presented the framework of the proposed CBA methodology and discussed
how it can be used in practice. The existing project appraisal process (Australian
Transport Council, 2006a) was reviewed to determine how the proposed methodology
can be incorporated into the existing process. Detailed framework of the proposed
methodology was then presented and the added steps to the existing CBA methodology
were highlighted. Practical considerations, such as how the analysis can be conducted
and how the outcomes can be interpreted, were discussed. Future research needed to
improve the proposed methodology was discussed in the final section. The key future
132 Chapter 9: Conclusion
research will be to determine the appropriate forms of probability distributions of input
variables, particularly of those that have not been previously studied.
9.2 REVIEW OF THE RESEARCH QUESTIONS
The following sections address the research questions, which are restated as follows:
1. How have various toll road projects been evaluated using CBA in practice?
2. Does the extant CBA methodology that is used to evaluate toll road projects
properly reflect the net impacts and risks to the community of a toll road?
3. Can CBA results properly reflect the source/s of risks of a toll road project
by incorporating a stochastic approach?
4. How does altering treatments of some impacts of a toll road project in CBA
improve its outcomes in terms of reflecting net impacts and risks to the
community?
9.2.1 Research Question 1
The first research question was addressed in Chapter 4, by reviewing previously
conducted CBA for the purpose of evaluation of toll road projects. The Cost-Benefit
Analysis (CBA) of toll road projects generally include travel time saving, vehicle
operating cost saving, crash cost saving, environmental and external cost saving,
capital cost, and operation and maintenance cost. These impacts are monetised using
transport cost unit prices. The outcome of the CBA is represented as Benefit-Cost
Ratio (BCR), which is a ratio of benefits to costs.
There are often technical inconsistencies between the CBA that is conducted for
different projects. This can be explained by time and resource availabilities at the time
of the analysis. Many projects with insufficient BCR have still proceeded, which
indicates that other intangible factors that were not considered in CBA have been given
substantial consideration in the decision making. Also highlighted was the complexity
of evaluating a single transport infrastructure item while its performance depends on
its surrounding transport network. For instance, when several roads are opening within
a short span of time within the same network, their performance will be at their best
when all are opened.
Tolls are generally treated as financial transfers in practice. Further
considerations revealed that whether tolls should be treated as financial transfers for
Chapter 9: Conclusion 133
privately operated toll road projects, needs to be further examined. Additionally, the
calculation of RV, estimation of discount rate and the impacts of various risk-sharing
arrangements also needs to be investigated for Public-Private Partnership (PPP) toll
road projects.
9.2.2 Research Question 2
The second research question was addressed in Chapter 3 and Chapter 4. CBA is a
well-established project evaluation methodology (van Wee & Rietveld, 2014), which
considers project impacts from wide perspectives, including road users, non-road users
and the road operator (Decorla-Souza et al., 2013; Mackie et al., 2014). BCR reflects
the net impact of the project. However, with the variations of various delivering
strategies and risk-sharing arrangements, the treatment of some impacts need to be
considered carefully. For instance, tolls are generally treated as financial transfers by
assuming that the public operator collects the tolls. For many of the recent toll road
projects, tolls are instead collected by the private operator. The treatment of tolls
traditionally does not differ between a publicly operated toll road and a privately
operated toll road in CBA. Whether treatments of impacts need to be altered to
properly reflect the net impacts and risks in CBA need to be investigated.
9.2.3 Research Question 3
The third research question was addressed in Chapter 5. The Monte Carlo simulation
approach was incorporated into CBA to demonstrate stochastic representation of BCR.
Risk profiles can be developed using statistical inferences on the basis of the stochastic
BCR. The risk profile demonstrated the risk effectively in an empirical manner. The
risk can be assessed across perspectives and scenarios using the stochastic BCR.
Sources of risks can be identified by observing the outcome BCR for
combinations of deterministic input variables and stochastic input variables. This study
revealed that annual average daily traffic (AADT), vehicle hours travelled saving
(VHTS), travel time unit price and capital cost influence the outcome BCR most
significantly.
9.2.4 Research Question 4
The fourth research question was addressed in Chapter 6 and Chapter 7. A toll road
project case and a toll tunnel project case were synthesised on the basis of existing
major road projects and evaluated using CBA. Altering treatments of impacts were
134 Chapter 9: Conclusion
investigated by considering the perspectives of “toll as a financial transfer” (TT) and
“toll as an end-user cost” (TC). This revealed that treating tolls as the cost to the
community is a reasonable and valid approach. Other payments that are often used in
toll road projects, such as minimum revenue guarantee, were also considered and the
treatments of impacts were altered accordingly to each scenario across the
perspectives. The shift of risk when the project is operated by the private operator was
observed in the risk profile when treatments were altered. This indicates that
considering the perspectives of TT and TC and altering treatments of some impacts in
CBA appropriately reflects the net impacts and risks of a toll road project in the
outcome BCR and risk profiles.
9.3 CONTRIBUTION TO THEORY
Many past studies (Aldrete et al., 2012; Anas & Lindsey, 2011; Bain, 2009; Bel &
Foote, 2009; Carpintero, 2010; Li & Hensher, 2010; Liyanage & Villalba-Romero,
2015; Mishra et al., 2013; Odeck, 2008; José Manuel Vassallo et al., 2012; Welde,
2011; L. Zhang, 2008; Z. Zhang et al., 2013) evaluated toll road projects from different
points-of-view than CBA. Various studies exist with regard to financial analysis and
traffic forecasting studies of toll road projects (Bain, 2009; Li & Hensher, 2010;
Welde, 2011). In comparison, CBA evaluates a project with respect to transport
benefits and costs. This allows assessment of whether the project is beneficial to the
community, instead of evaluating projects solely based on financial impacts. This
study extended the knowledge of evaluation of a toll road project by considering
transport impacts using CBA.
Considering “toll as a financial transfer” (TT) and “toll as an end-user cost” (TC)
perspectives in CBA has not been studied, although different perspectives have
previously been examined in financial analysis (Mishra et al., 2013). Treatments of
some project impacts in CBA were altered by considering these perspectives in this
study. This allowed exploration of whether the TC perspective is a valid approach. The
outcomes of the evaluation confirmed that the shift of risk of a privately delivered
project can be observed using the proposed methodology under the TC perspective.
How CBA can be conducted by solely evaluating the project from the public
perspective was examined by considering the TT and TC perspectives. This is a
significant contribution to the academic study, which can suggest a number of future
Chapter 9: Conclusion 135
studies on incorporating different perspectives into CBA of various infrastructure
types.
Generally, tolls are considered as a financial transfer and enter into CBA
calculations only to the extent that they cause a change in micro-economic behaviour
(Decorla-Souza et al., 2013). This study determined that treating tolls as the cost to the
community is a valid approach under the TC perspective. This is a significant
contribution to the extent knowledge.
This study found that by incorporating a stochastic approach into CBA of a toll
road project, the shift of risk can be analysed empirically, which demonstrated
applications of the stochastic CBA. This study also examined the effectiveness of
various measures to evaluate toll road projects. Coefficient of variation (CV) was
found to be an effective measure of risk of projects with any Benefit-Cost Ratio (BCR).
Percentiles and cumulative probability distribution graphs can also represent the
spread of the outcome stochastic BCR, while CV quantifies the level of risk in an
empirical manner, which can easily be compared across scenarios.
Although, Asplund and Eliasson (2016) claim that transport investment and
transport demand risks affect the CBA results the most, this study showed that the risks
of travel time unit price, VHTS, and traffic growth, as well as AADT and capital cost
affected the outcome BCR the most. This is consistent with that the travel time savings
most contributed in the overall benefits.
The one-way probabilistic sensitivity analysis of variation in risk characteristics
demonstrated the assessment in terms of the vulnerability towards particular sources
of risks across perspectives and scenarios. The outcome of the assessment heavily
relies on the model assumptions, however, various sensitivity analyses can be
conducted to further investigate the relationship between the risk that the host
government is bearing and various risk-sharing arrangements using the proposed
methodology. This would extend knowledge, particularly in terms of better allocating
traffic and revenue risks of a toll road project through various risk-sharing
arrangements.
9.4 CONTRIBUTION TO PRACTICE
The key contribution of the proposed methodology is the representation of impacts to
the community by solely evaluating the project from the public perspective, using
136 Chapter 9: Conclusion
Cost-Benefit Analysis (CBA). Not only contributing to the academic study
significantly, this can also provide significant contribution to practice. The host
government acts as the decision-maker in the project appraisal of major road projects
and is responsible to ensure that the benefits of the decision outweigh the costs. Many
recent major road projects, such as those examined in this study (AECOM Australia,
2013, 2014; Arup, 2010a; Brisbane City Council, 2010; Connell Wagner, 2004;
Queensland Government, 2008; SKM & Connell Wagner, 2006; The Allen Consulting
Group, 1996), have been delivered through Public-Private Partnership (PPP) schemes.
The proposed methodology provides the host government with a tool to evaluate major
PPP projects from the public perspective. For the purpose of equitable decision
making, the proposed methodology can be used by government agencies, transport
economists and transport planners, in order to present CBA outcomes to the decision-
makers.
The proposed methodology can be implemented into the existing project
appraisal process by incorporating it into CBA phase. The framework of the proposed
methodology (see Figure 8.2) clearly displays the added steps and how it can be
conducted as part of the existing framework.
Decorla-Souza et al. (2013) argue that a broad view of the public as a whole,
including users and nonusers of the project, need to be considered, in order to assess
various delivery options including PPP schemes. The proposed methodology assesses
various delivery options by using CBA. This potentially provides a link between CBA
and procurement.
CBA calculation does not require any rigorous statistical or modelling
techniques and can be conducted easily using spreadsheet analysis. The Monte Carlo
simulation can also be conducted using a spreadsheet, such as Excel. Tools other than
spreadsheet can also be used, however they need to be able to conduct the Monte Carlo
simulations and analyse stochastic representation of the analysis outcome.
Interpretations of statistical inferences can be a complex task without knowledge of
statistics. Guidance on interpretations of risk profiles was therefore provided in this
thesis.
This study demonstrated graphical representations of the net impacts and risks
of the project using cumulative probability distributions, and box-and-whisker plots.
Interpretations of these graphs are summarised in Table 8.2. Visually representing the
Chapter 9: Conclusion 137
analysis outcome is particularly useful for the decision-maker. For instance, the length
and the position of each box in box-and-whisker plots represent the net impacts and
risks of the project visually across scenarios. The decision-makers can efficiently make
a well-informed decision without having to read and interpret numerously represented
outcomes.
9.5 RECOMMENDATIONS FOR FUTURE WORK
➢ Exploring variety of probability distributions
The impacts of using a range of different probability distributions for input variables
were not explored in this study. The level of impacts of using different probability
distributions on the CBA outcome can be explored. This allows to identify the input
variables that the most impact the outcome when types of probability distributions are
changed. Additionally, past data can be statistically studied to determine the types of
probability distributions that the real data follows.
➢ Incorporating ramp-up period
The length of ramp-up period can differ between projects. The impacts of
incorporating a range of ramp-up periods using the proposed methodology, in order to
investigate their influences on the CBA outcome.
➢ Testing the sensitivity of a range of discount rates
A wide range of discount rates are used in different countries. The sensitivity of using
different discount rates can be investigated, in order to explore their influences on the
CBA outcome.
➢ Conducting multi-way sensitivity
One-way probabilistic sensitivity was conducted in this study. Multi-way probabilistic
sensitivity can be conducted on a number of input variables. Particularly, the input
variables with some correlations can further be investigated through the multi-way
sensitivity analysis. For instance, this study showed that travel time saving is the major
benefit of a major road project. Therefore, multi-way probabilistic sensitivity analysis
is recommended for those input variables that influence the travel time saving.
Additionally, the elasticity of the toll price and traffic volume can be incorporated into
the analysis.
➢ Applying the proposed methodology to other types of projects
138 Chapter 9: Conclusion
Similar studies on various transport infrastructure projects other than toll road projects
are also recommended as future studies. Applications on various types of Public-
Private Partnership (PPP) projects would further extend the knowledge of Cost-Benefit
Analysis (CBA).
➢ Incorporating WEB
As has been highlighted in the literature review, the guidelines that provide guidance
on accounting wider economic benefits (WEB) in CBA will be published in Australia
in the near future. The WEB methodology needs to be reviewed when ready, in order
to incorporate the WEB in the proposed methodology.
9.6 CONCLUDING REMARKS
This study examined the impacts and risks of a toll road project to the community, in
order to reflect them in Cost-Benefit Analysis (CBA). Literature and previously
conducted CBA were reviewed to highlight any limitations and difficulties of CBA.
The outcomes of the stochastic CBA were examined to observe how the sources of
risks are reflected in the outcomes. A toll road project case and a toll tunnel project
case were synthesised on the basis of existing toll road projects, in order to determine
the methodology that best reflects the net impacts and risks of a toll road project to the
community. The outcomes of CBA of a toll road project, when treatments of project
impacts vary, were investigated by examining various payment movements. This study
concludes that the estimation of net impacts and risks of a toll road project to the
community for the purpose of project evaluation can be improved by considering the
treatment of project impacts and performing stochastic CBA. Additionally, this study
proposed the CBA methodology that incorporates considerations of multiple
perspectives, in order to best reflect the net impacts and risks to the community, and
demonstrates them in an empirical manner in risk profiles.
List of Publications and Awards 139
List of Publications and Awards
Journal publications:
Chi, Sae, Bunker, Jonathan M., & Teo, Melissa (2017) Measuring impacts and risks
to the public of a privately operated toll road project by considering perspectives
in cost-benefit analysis. Journal of Transportation Engineering, 143(12), Article
number-04017060
Conference publications:
Chi, Sae, Bunker, Jonathan M., & Kajewski, Stephen L. (2016) Comparative case
study on cost-benefit analysis for toll road projects. In 27th ARRB Conference
2016, 16-18 November 2016, Melbourne, Vic. (Peer reviewed conference paper)
Chi, Sae, Bunker, Jonathan M., & Kajewski, Stephen L. (2016) A review of project
evaluation methodologies to address net impacts and risks of toll road projects
to the community. In Conference of Australian Institutes of Transport Research
2016, 11-12 February 2016, Brisbane, Qld. (Non-peer reviewed conference
paper)
Awards:
• Young Research Award 2016 from ARRB Academy
• Regional Student Researcher Prize (Queensland and Northern Territory)
2016 from ARRB and Roads Australia
• Australasian Prize 2016 (Best Student Researcher at an Australian
University) from ARRB and Roads Australia
• High Degree Research Student Award for December 2016 from Science and
Engineering Faculty at Queensland University of Technology
References 141
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