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Wycombe District Local Plan Highway Assignment Model Specification Report March 2013

Wycombe District Local Plan - HAMSR - Final.doc

Document Control Sheet BPP 04 F8 Version 16: October 2013

Project: Wycombe District Local Plan Client: Transport for Buckinghamshire Project No: B1279891/RE

Document Title: Highway Assignment Model Specification Report Ref. No: WDLP/HWMSR

Originated by Checked by Reviewed by

ORIGINAL

NAME NAME NAME

Christine Paine Dharmender Singh Theo Genis

Approved by NAME As Project Manager I confirm that the

above document(s) have been subjected to Jacobs’ Check and Review procedure and that I approve them for issue

INITIALS

Rich Smith

DATE 05/03/13 Document status: Draft

REVISION A NAME NAME NAME

Christine Paine Dharmender Singh Theo Genis



INITIALS

Rich Smith

DATE 15/03/13 Document status: Final

REVISION NAME NAME NAME



INITIALS

DATE Document status

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Contents

1 Introduction 1

1.1 Overview 1

1.2 Purpose of Report 1

1.3 Background 1

1.4 Model History 2

2 Proposed Uses of the Refresh Model and Key Design Considerations 3

2.1 Proposed Uses of the Model 3

2.2 Key Design Considerations 3

3 Model Standards 6

3.1 Validation Criteria and Acceptability Guidelines 6

3.2 Convergence Criteria and Standards 7

3.3 Traffic Volume and Journey Time Data 7

4 Key Features of the Model 10

4.1 Fully modelled Area and External Area 10

4.2 Zoning System 11

4.3 Network Structure 12

4.4 Centroid Connectors 12

4.5 Time Periods 13

4.6 User Classes 13

4.7 Assignment Methodology 13

4.8 Generalised Cost Formulations and Parameter Values 13

4.9 Capacity Restraint Mechanisms 14

4.10 Application of Variable Demand Modelling 14

5 Calibration and Validation Data Specification 15

5.1 Traffic Counts and Roadside Interview Sites 15

5.2 Traffic Counts for Matrix Estimation 15

5.3 Traffic Counts for Validation 16

5.4 Journey Time Surveys for Calibration and Validation 16

6 Network Development Methodology 17

6.1 Network Data, Coding and Checking 17

7 Trip Matrix Development 18

7.1 Travel Demand Data 18

7.2 Partial Trip Matrices from Surveys 18

7.3 Trip Synthesis 18

7.4 Merging Data from Surveys and Trip Synthesis 18

8 Network Calibration and Validation Methodology 19


8.1 Network Calibration 19

8.2 Network Validation 19

9 Route Choice Calibration and Validation 20

9.1 Route Choice Calibration 20

9.2 Route Choice Validation 20

10 Trip Matrix Calibration and Validation Methodology 21

10.1 Trip Matrix Calibration 21

10.2 Trip Matrix Validation 21

11 Assignment Calibration and Validation Methodology 22

11.1 Assignment Calibration 22

11.2 Assignment Validation 22

12 Summary of Model Development, Standards Proposed and Fitness for Purpose 23

12.1 Summary of Model Development 23

12.2 Summary of Standards Proposed 23

12.3 Proposed Assessment of Fitness for Purpose 23

Appendix A Current Local Model Validation Report Appendix B Traffic Volume Data Availability

Appendix C M40 Junction 4 (Handy Cross) TRADS Data

List of Tables Table 3-A Screenline flow validation criterion and acceptability guideline 6

Table 3-B Link flow and turning movement validation criteria and acceptability guidelines 7

Table 3-C Journey time validation criterion and acceptability guideline 7

List of Figures Figure 3-A Variation in daily traffic flow at M40 Junction 4 between 2008

and 2012 8

Figure 4-A Extent of fully modelled area 10

Figure 4-B Extent of external area 11

Figure 4-C Zoning system for High Wycombe urban area 12

Wycombe District Local Plan - HAMSR - Final.doc 1

1 Introduction

1.1 Overview

Jacobs are framework consultants to the Transport for Buckinghamshire Alliance between Ringway Jacobs and Buckinghamshire County Council (BCC). Under the terms of this contract, Jacobs are commissioned to undertake traffic planning, modelling and assessment studies on behalf of the County Council, working in partnership with District Councils. Jacobs was commissioned by Buckinghamshire County Council and Wycombe District Council (WDC) in November 2012 to develop undertake a transport and land use assessment to support and inform the development of the new Wycombe District Local Plan (WDLP). Jacobs manages a suite of transport models and assessment tools on behalf of the Councils and these models are used to inform local planning processes. Jacobs have undertaken a review of the existing highway assignment model for High Wycombe in preparation for the development and assessment of options in support of the WDLP. The model will be used to perform comparative assessments of new land use quantums and the impacts of different locations for new land use. The existing VISUM model1 (“the existing model”) has a 2010 base (i.e. it has been validated to count data from 2010) and was developed using matrices from the 2006 CONTRAM model. These matrices were developed using Roadside Interview Data from May 2006. The existing model was developed according to the guidelines in DMRB and WebTAG for highway assignment modelling at the time. However, in August 2012 new guidance in the form of WebTAG unit 3.19 (“the guidance”) was released with a specific focus on highway assignment modelling. It was deemed prudent to review the existing model against this guidance and to create an updated model (“the refresh model”) before proceeding with the Wycombe Local Plan testing.

1.2 Purpose of Report

The purpose of this report is to set out the changes proposed to the existing model to adapt it to the guidance set out in WebTAG 3.19, and to provide a technical overview of the specification to which the refresh model will adhere. More detailed information on the existing base model is included in the Local Model Validation Report1.

1.3 Background

In March 2012 the National Planning Policy Framework (NPPF) was published, consolidating policy statements, circulars and guidance documents into a single concise framework. The NPPF outlines the Government's economic, environmental and social planning priorities for England and assists the production of robust local and neighbourhood plans and development management decisions. Local planning authorities are required to prepare plans that accommodate new development; meeting objectively assessed local needs and priorities.

1 as described in the High Wycombe Transport Model - Local Model Validation Report (Nov 2011)


WDC is developing a new Local Plan for the District. The Plan will replace the adopted Core Strategy (2008) as well as the saved policies from the existing Local Plan (2004). The new Local Plan will sit alongside the Delivery and Site Allocations (DSA) Plan for Town Centres and Managing Development document, once this is adopted. WDC states that the new Wycombe District Local Plan will:

• set housing targets for the district and address strategic housing issues including housing and mixed use allocations;

• include policies and proposals for the protection and provision of employment land; and

• include site-specific proposals for local communities setting out detailed policies to manage development.

1.4 Model History

An existing strategic highway assignment model built using the PTV VISUM modelling suite includes the urban area of High Wycombe1. This model has a 2010 base for the morning (AM) and afternoon (PM) peak hours and was developed using matrices from a 2006 CONTRAM model. A forecast “Do Minimum” model for 2022 was developed to represent conditions on the highway network under forecast demand with committed land use and transport infrastructure included. The assumptions informing this model as described in the Forecasting and Assumptions Report2. In addition, a detailed TRANSYT model of the M40 Handy Cross junction (reviewed and approved by the Highways Agency) and a VISSIM model of High Wycombe Town Centre (developed by Jacobs on behalf of BCC) are also available. All these models have base years of 2010 or earlier.

2 High Wycombe Transport Model – Traffic Forecasting and Assumptions (July 2012)


2 Proposed Uses of the Refresh Model and Key Design Considerations

2.1 Proposed Uses of the Model

The refreshed highway assignment model (base and forecast) for Wycombe will be used to provide technical input to:

• the assessment of current and forecast traffic demand to identify opportunities and constraints within High Wycombe and surrounds (i.e. set out current transport deficits and identify future deficits)

• establish an up-to-date traffic baseline and a forecast of future traffic conditions under a ‘Do Minimum’ scenario, which includes committed land use and infrastructure

• the assessment of the impact of additional housing and employment-related land use in and on the edge-of the urban area of High Wycombe and at other locations across Wycombe district to inform decisions about overall quantums of development

• the provision of a comparative assessment of the traffic and transportation implications of locating new land use development in particular areas

• the consideration of the impact and performance of potential new transport infrastructure and more localised transport network improvements

• the assessment of strategic site options on their absolute and relative performance and identify potential/indicative mitigation measures

2.2 Key Design Considerations

The key design aspects considered in this model specification report are:

• adapting the existing model reporting to conform to the new WebTAG guidance (Unit 3.19)

• consideration of the age of the underlying RSI data used to inform the highway assignment matrices.

A) Improvements to be made to the existing model Improvements required by the guidance:

• review of journey time validation and its reporting;

• Confirmation that convergence criteria are met over four continuous iterations;

• validation of (and associated reporting) key junctions in the network such as Handy Cross, the Abbey Way roundabouts and the junction of West Wycombe (A40)/Chapel Lane. During model validation additional key junctions will be identified;

• review and reporting of the independence of traffic counts used for validation, as well as application of screenlines and cordons in matrix calibration;

• review of saturation flow values and minimum gap values assumed at junctions.

General improvements to the existing model:


• review and update of traffic signal junction timing plans;

• application of stress tests (increase/decrease of traffic demand by 10%) to the model as a whole and a review of the resulting junction operation and route selection;

• application of stress tests (application of new trips from a specific development locations including in new zones) and a review of the resulting junction operation and route selection. in order to check the model for overall robustness;

• review of user classes (in particular Heavy and Light goods vehicles) included in the assignment matrices in the light of available traffic composition data;

• check of the VDM requirement by testing elasticity values in accordance with WebTAG unit 3.10;

• revalidation of the model to 2013 traffic levels (incorporating some new traffic count data, existing counts where available and permanent automatic traffic count data to update the 2010/2011 database of traffic flows). 2013 journey time data from Trafficmaster data will be incorporated into the revalidation.

More details on the traffic data to be used for model validation are included under Chapter 3.3 and Appendices B and C. B) Improvements to be made to the Local Model Validation Report The report will be restructured in accordance with Appendix F of WebTAG unit 3.19, and the following sections reviewed:

• improved definition of Heavy and Light Goods Vehicles in the model;

• description of user classes included in the model;

• description of speed-flow curves applied in the model;

• description of generalised cost formulation applied in the model;

• mapping out of validation and calibration count locations, screenlines and cordons;

• validation against 2011 census land use data (as available);

• descriptions of route choice and network calibration and validation;

• changes resulting from the application of matrix estimation to be described;

• convergence results to be provided in greater detail;

• more information/links to the previous 2007 CONTRAM model Local Model Validation Report, in particular with reference to the matrix development and validation;

• sections describing the detailed model validation of key junctions such as Handy Cross junction; and

• updated model calibration and validation results to 2013 equivalent count data.

C) Consideration of the Age of Underlying RSI Data According to paragraph 8.1.1 of the new guidance, RSI data taken from previous models should not be older than 6 years. As the existing model is based on RSI data collected in May 2006, this part of the guidance would not be met. In order to rectify this, a series of costly and inconvenient Roadside Interview Surveys would need to be arranged in Spring 2013 at a minimum of 12 locations in and around High Wycombe (with preliminary costs estimated at more than £90k).


As the cost and programme impacts of such a survey requirement cannot be accommodated within the Local Plan programme, an alternative course of verifying the suitability of the existing model with the District and County authorities, as well as the Highways Agency will be pursued. This verification and justification for the approach is based on the following:

• The refresh model would be improved according to the new guidance, and updated to a 2013 base, taking into account the latest traffic count data and network conditions;

• Data analysis (using counts from different years) will be used to demonstrate whether there have been any strategically significant changes in traffic volumes as a result of new land use and transport network changes. This will inform the hypothesis that traffic distribution and composition has not changed significantly from May 2006 (local land use changes excluded), and that the 2006 data can be confidently used.

• The outcome of this analysis will be reviewed with the District and County Councils, as well as the Highways Agency.

• Limited matrix estimation will be applied to the 2006 RSI data and where undertaken the impact/changes will be clearly quantified as part of trip matrix validation.

• A series of ‘stress tests’ will be undertaken to confirm that the refresh model is fit for its stated purpose, in particular in reflecting the impact on the Highways Agency network.

The refresh model will also consider the study area boundary and zoning system of the model in order to ensure that areas of potential land use development are covered within the scope of the model.


3 Model Standards

3.1 Validation Criteria and Acceptability Guidelines

In accordance with the guidelines in TAG Unit 3.19, the validation of the highway assignment model will include comparisons of the following:

• assigned flows and counts totalled for each screenline or cordon, as a check on the quality of the trip matrices;

• assigned flows and counts on individual links and turning movements at junctions as a check on the quality of the assignment;

• assigned turning flows and counts at key junctions in the highway network;

• modelled and observed journey times along routes, as a check on the quality of the network and the assignment.

A) Trip Matrix Validation

For trip matrix validation, the measure which will be used is the percentage differences between modelled flows and counts at screenline level. The reporting will provide information on the quality of the trip matrices in accordance with the validation criterion and acceptability guideline for screenline flows as defined in Table 3-A.

Criterion Acceptability Guideline

Differences between modelled flows and counts should be less than 5% of the counts

All or nearly all screenlines

Table 3-A Screenline flow validation criterion and acceptability guideline

The screenlines will be designed to satisfy as many of the following as possible:

• normally be made up of 5 links or more;

• comparisons presented separately for

• (a) roadside interview screenlines;

• (b) screenlines used as constraints in matrix

• (c) screenlines used for independent validation;

• comparisons presented separately for each modelled period

B) Link Flow and Turning Movement Validation Link flow validation will be based on the following measures:

• the absolute and percentage differences between modelled flows and counts

• the GEH statistic, which is a form of the Chi-squared statistic that incorporates both relative and absolute errors

( )

+

−

=

2

2

CM

CM

GEH

where M is the modelled flow and C is the observed flow.


The validation criteria and acceptability guidelines for link flows and turning movements are defined in Table 3-B.

Criterion Description of Criterion Acceptability Guideline

1 Individual flows within 100 veh/h of counts for flows less than 700 veh/h

> 85% of cases

Individual flows within 15% of counts for flows from 700 to 2,700 veh/h

> 85% of cases

Individual flows within 400 veh/h of counts for flows more than 2,700 veh/h

> 85% of cases

2 GEH < 5 for individual flows > 85% of cases

Table 3-B Link flow and turning movement validation criteria and acceptability guidelines

C) Journey Time Validation For journey time validation, the measure which should be used is the percentage difference between modelled and observed journey times, subject to an absolute maximum difference. The validation criterion and acceptability guideline for journey times are defined in Table 3-C.

Criterion Acceptability Guideline

Modelled times along routes should be within 15% of surveyed times (or 1 minute, if higher)

> 85% of cases

Table 3-C Journey time validation criterion and acceptability guideline

Journey time validation will be presented separately for each modelled period for all vehicle types together.

3.2 Convergence Criteria and Standards

The convergence criteria for the model will be set to match those set out in Table 4 of the guidelines (Unit 3.19). The VISUM software platform provides output from the model assignment run in the form of %GAP and the % change in link or turning flows over consecutive assignments in the form of a GEH statistic. This GEH statistic will be adapted to represent the same standards as set out in the guidance. Convergence statistics over at least four consecutive iterations will be included in the reporting.

3.3 Traffic Volume and Journey Time Data

Traffic Volume Data - General The traffic data that will be used in the refresh of the highway assignment model includes the majority of the strategic road network throughout the detailed modeled area, as shown in Appendix B, and is a combination of existing count data from BCC and new count data. Existing count data from June 2012 or later will be used (and scaled up appropriately from nearby ATC counts) to supplement new data collected in March and April 2013.


Traffic Volume Data – M40 Junction 4 (Handy Cross) M40 Junction 4 (Handy Cross) is a key junction in the network, and specific attention has been given to the traffic data to be used to validate this node. The collection of new traffic data presents programming issues, as the indication from suppliers are that counts could only be performed after the Easter school holidays. The Local Plan development programme requires the model to be updated during April and the data would not be available before early May. Furthermore, there is the risk that the day of the surveys could be affected by unusual traffic conditions. Hence, the approach proposed for the validation of the movements through this junction is a dual approach. Video surveys of the junction during April (following the Easter break) will be pursued. But should the updated data not be available in time for the model refresh, or technical issues compromise the outputs, data collected in 2008 (origin-destination surveys) will be used. The 2008 data will be scaled from 2008 to 2013 traffic levels using data from the HA Traffic Information database (TRADS) for all the approaches to the junction (as shown in Appendix C). This approach is supported by the following:

• The change in traffic levels on the approaches between 2008 and 2013 has been reviewed and it confirms that there has been very little change in daily traffic demand through the junction. This is demonstrated by Figure 3-A, which shows the variation in daily volumes for an average 2-week weekday period in June between 2008 and 2012 (TRADS sites with available data).

TRADS Average Weekday Traffic (AWT) Data for the Month of June

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

2008_AWT 2009_AWT 2010_AWT 2011_AWT 2012_AWT

5605

5606

5607

5608

30025552

4095

4096

4098

4099

4100

4107

30012911

Figure 3-A Variation in daily traffic flow at M40 Junction 4 between 2008 and 2012

• Based on the lack of major land use and road network changes over this time period (with the exception of the opening of the Eden Shopping Centre), the distribution of turning movements through the junction would not be expected to have changed.


Journey Time Data Journey time data gathered from ANPR surveys in 2010 was used as part of the existing model validation. This data will be supplemented with Trafficmaster journey time data for key routes collected during 2012 in order to validate journey times in the refreshed model.


4 Key Features of the Model

4.1 Fully modelled Area and External Area

The fully modelled area of the existing strategic model is shown in Figure 4-A. This area is slightly larger than the urban area of High Wycombe. As required by the guidance, the modelling of this area is characterised by:

• small zones, decreasing in size in proportion to the density of land use in the zone (i.e. smaller zones in the town centre);

• all trip movements are represented;

• the network and junctions are modelled in detail, providing a close representation of the network as it is on the ground.

As part of the update process, the boundary of the fully modelled area will be examined in relation to potential development sites (applicable to any forecast modelling) and amended if necessary.

Figure 4-A Extent of fully modelled area


The external area is the remainder of the network lying outside the fully modelled area. The extent of the external area is shown in Figure 4-B. This area has:

• larger zones

• fixed speed links

• a skeleton road network

• only trips to, from and through the fully modelled area (with the exception of the M40)

The main purpose of this wider network is to allow trips to re-route through or avoid the fully modelled area.

Figure 4-B Extent of external area

4.2 Zoning System

The zones in the original CONTRAM model were based on 2001 Census Enumeration Districts. This zoning system was maintained in the 2010 models. The detailed zoning system for the fully modelled area of the existing model is shown in Figure 4-C. It may be necessary to make minor adjustments to the zone


structure to ensure that specialised land uses such as schools and car parks are included in their own zones, and that the model is compatible with census output areas. Empty zones will also be added to facilitate testing of new land uses in the future.

Figure 4-C Zoning system for High Wycombe urban area

4.3 Network Structure

Within the fully modelled area all roads that carry vehicular traffic, including those in residential areas, are represented. Junction modelling is very detailed (including junction form, operation, gap acceptance criteria and fixed time signal settings) and zones are quite small (refer to Figure 4-C). In the external area only major roads and other roads known to be used as “rat runs” are included. Links are fixed speed and few junctions are modelled in detail. Most zones are based on wards or larger administrative areas.

4.4 Centroid Connectors

Trips to and from zones are loaded onto the network from the zone centroid (centre of gravity of the zone) using specialised links known as centroid connectors. The points at which these connectors load on to the network have been chosen to reflect actual access points and to avoid major junctions.


Ideally, a zone should have only one connector. The model will be examined to review whether any zones need to be split or connectors adjusted in order to stabilise loading during assignment.

4.5 Time Periods

The model time periods were inherited from the original CONTRAM model and are set as the morning (AM) peak hour (08:00-09:00) and afternoon (PM) peak hour (17:00-18:00). These were confirmed through examination of ATC data for a number of sites in the town. It is not intended to change these peak hours. Inter-peak or off-peak models have not been developed.

4.6 User Classes

The existing model includes three private transport modes - the 2006 vehicle purpose split was not incorporated into the base model as no intensive economic analyses was planned. Hence only car, LGV and HGV were included as user classes, with one matrix for each mode. For the existing model, specific calibration of the LGV and HGV matrices was not applied due to a lack of observed traffic count data. This will be reviewed in the updated model – if adequate data is available the LGV and HGV matrices will be calibrated to 2013 traffic counts. If adequate data is not available then the LGV and HGV matrices will be adjusted by factors representing the overall growth in vehicle movements observed between 2006 and 2013. For the updated model, the underlying trip purpose data from the 2006 RSI matrices will be retained and their reliability determined through a review of the required changes to the 2006 matrices in order to match observed traffic volumes in 2013.

4.7 Assignment Methodology

The assignment procedure to be adopted for the highway model is based on an equilibrium assignment with multiple demand segments for a typical hour in the morning and evening peaks, operating within the constraints of the convergence criteria set out in this report. The assignment will be path-based and will not include disaggregated time-slices or blocking-back responses.

4.8 Generalised Cost Formulations and Parameter Values

VISUM can be set to consider route costs as a “generalised cost” which is a combination of time, distance and monetary charges e.g. tolls. The formula used is as follows:

C = PPM*T + PPK*D + M

Where:

C = Generalised Cost PPK = Pence per Kilometre – converts distances into generalised costs. PPM = Pence per Minute – converts times into generalised cost. T is time in units of minutes D is distance in kilometres M is monetary charge in pence


The value of M will be set to 0 as there are no fixed tolls in the base model network. Values for the PPM and PPK parameters will be derived from Unit 3.5.6 of WebTAG for 2013 conditions and similarly for future year scenarios.

4.9 Capacity Restraint Mechanisms

Capacity restraint will be applied in the fully modelled area using a combination of link-based speed/flow relationships and detailed junction modelling. VISUM applies what is called Intersection Capacity Analysis (ICA) to detailed junctions during the highway assignment, which reflects the algorithms in the US-based Highway Capacity Manual. This reflects the available capacity for turning movements at a junction against the opposing movements.

4.10 Application of Variable Demand Modelling

Whilst the inclusion of a Variable Demand Modelling (VDM) component to the Wycombe model would theoretically add an additional response to the assignment results produced by the model, the added complexity and cost of incorporating this against limited data sources means that a simpler highway assignment-only approach will be adopted. The proposed approach is to incorporate basic VDM testing (as set out in WebTAG units 3.10) alongside stress tests applied to the calibrated model. If the VDM test results indicate a need for some form of VDM to be applied, this will be approached through the application of sensitivity testing to the forecast model results.


5 Calibration and Validation Data Specification

5.1 Traffic Counts and Roadside Interview Sites

Traffic counts (existing and planned) will be applied to the following purposes:

• re-expanding the 2006 roadside interview matrices;

• calibrating 2013 trip matrices by means of matrix estimation; and

• validation of the 2013 trip matrices. The following 95% confidence intervals for traffic counts will be assumed:

• automatic Traffic Counts: total vehicles: ± 5%;

• manual Classified Counts: total vehicles: ± 10%;

• manual Classified Counts: cars and taxis: ± 10%;

• manual Classified Counts: light goods vehicles: ± 24%;

• manual Classified Counts: all goods vehicles: ± 18%. A) Roadside Interview Survey (RSI) Sites Roadside interviews were carried out at twelve sites in High Wycombe in May 2006 as part of the CONTRAM model building process. They form a cordon around the fully modelled area No new RSI surveys are planned. B) Automatic Traffic Count (ATC) Data A good quantity of recent ATC data is available for the Wycombe urban area from both permanent and temporary sites. Additional data collected in 2013 will be incorporated into the model. C) Manual Classified Count (MCC) Data There are a good number of recent manual classifies junction counts available throughout the Wycombe urban area. Data from additional sites surveyed in 2013, particularly along the eastern A40, where there has been considerable commercial development since 2010, will be incorporated into the model.

5.2 Traffic Counts for Matrix Estimation

When calibrating the existing model, a comparison of traffic survey data from 2006 and 2010 indicated that traffic growth was not uniform across the network. Therefore the 2006 matrix was calibrated to 2010 counts by scaling the matrix on a cordon and screenline basis. It is proposed to adopt a similar strategy to update from 2006 to 2013. In order to facilitate this process, ATC counts are planned at all twelve of the 2006 RSI locations. A selection of new and existing counts organised into screenlines will be used to assist in this process. The impact of matrix validation on the source 2006 RSI matrices will be recorded and reported in the revised Local Model Validation Report.


5.3 Traffic Counts for Validation

As in 2010, a selection of link counts, mainly from MCCs, will be retained for the purpose of trip matrix validation.

5.4 Journey Time Surveys for Calibration and Validation

Journey times are required for:

• calibrating cruise speeds (speeds between junction queues); and

• validating the model. It is proposed to use the extensive automatic numberplate recognition data (ANPR) collected in 2010 for calibration. Any new journey time data recorded by BCC or WDC will be incorporated. Validation will be performed by means of in-vehicle journey time observations along key routes.


6 Network Development Methodology

6.1 Network Data, Coding and Checking

The data for the model area was imported from the OS MeridianTM2 mapping. It includes information for links, such as length, geometry and the road type (e.g. A-road, B-road, minor road). Each link and junction was assigned a model-specific reference number. Additional characteristics were coded using aerial images, street level photographs and on-site observations. OS MeridianTM2 is updated regularly, so the opportunity will be taken to import any amendments to the network. A) Links

Links are coded by direction and the following characteristics are included:

• Number of lanes

• Link capacity (vehicles per hour)

• Maximum free-flow speed in kilometres per hour

• Class(es) of vehicles permitted to traverse the link (e.g. car, HGV, pedestrian, bus only)

• Traffic counts (for comparison with modelled flows). Link capacities are assigned based on a number of factors including link type, number of lanes, single or dual carriageway, street characteristics and amount of on-street parking. These factors and the speed limit pertaining to each link are used to determine the appropriate maximum free-flow speed. Tools available within the VISUM program suite will be used to check the “logic” of the network. The links are derived from a geographically correct source, therefore the link length parameter will be checked against both “crow flies” distance and the length of the link calculated by VISUM. B) Junctions Junctions are described by the following parameters:

• the junction type (traffic signals, roundabout, priority);

• the number of approach arms

• the number and width of lanes on each approach, flare length and lane discipline

• permitted and prohibited turns by vehicle type

• additional parameters according to junction type (e.g. saturation flows, signal timings and phasing, and gap acceptance)

As part of the validation of key junctions to be performed within the model refresh, the junction coding will be checked. The existing TRANSYT model of M40 Junction 4 (Handy Cross) will be used to verify the signal setting and delay assumptions in the VISUM model.


7 Trip Matrix Development

7.1 Travel Demand Data

The zones in the 2006 and 2010 models are built up from 2001 Census OAs. There is very close correspondence between 2001 and 2011 Census OAs in the Wycombe urban area, therefore Census data can be used to validate the level of demand in each model zone. 2011 census data available is at OA level for a number of variables including:

• number of households

• household size

• car/van availability

• mode of travel to work

• age profile

• employment status The 2011 Census journey to work matrices will not be available in time to inform this model refresh, but may be incorporated at a future date.

7.2 Partial Trip Matrices from Surveys

Observed matrices developed from 2006 survey data are available for each vehicle class and will be adapted according to the changes in observed traffic movements.

7.3 Trip Synthesis

Synthesised trip matrices for 2006 will be used as a basis for producing 2013 synthesised trip matrices for each vehicle type. For areas of new land use, trips will be synthesised using trip generation levels from the TRICS database and trip distributions from neighbouring zones with similar land use characteristics.

7.4 Merging Data from Surveys and Trip Synthesis

This will be an iterative process, whereby matrix estimation will be performed on the RSI cordon using the partial matrix. The 2006 synthesised trips will then be subject to matrix estimation while the 2013 partial matrix will be held constant. Some manual adjustments may be necessary in areas of the model where there have been land use changes since 2006 using the trip generation and distributions as set out in Section 7.3.


8 Network Calibration and Validation Methodology

8.1 Network Calibration

An initial trip matrix will be assigned to the coded network and checked to ensure that speeds and flows on links and delays at junctions are as expected. Routes between key origins and destinations will be checked to ensure that trips are not being diverted by faulty link or junction coding. Appropriate adjustments will be made to link and junction parameters.

8.2 Network Validation

The network validation will take the form of a thorough review of all the validation results from flows and journey times to ensure that there are no remaining areas for improvement.


9 Route Choice Calibration and Validation

9.1 Route Choice Calibration

The flow bundle capability of VISUM (which is similar to the “select link” function in SATURN) will be used to check that traffic routing is logical and accords with observed routing. Routing will be reviewed with BCC and WDC officers as required.

9.2 Route Choice Validation

The modelled routes between a selection of origin and destination zone pairs will be selected for route choice validation where these routes:

• relate to significant numbers of trips;

• are of significant length or cost;

• pass through areas of interest (e.g. key junctions or scheme impacted areas);

• include both directions of travel;

• link different compass areas (e.g. north to south, east to west, etc.); and

• coincide with journey time routes.

The routes modelled for each user class will be examined separately.


10 Trip Matrix Calibration and Validation Methodology

10.1 Trip Matrix Calibration

Matrix estimation will be used to refine the observed and synthesised matrices. The changes brought about by matrix estimation will be measured by the following means:

• scatter plots of matrix zonal cell values, prior to and post matrix estimation with regression statistics (slopes, intercepts and R2 values);

• scatter plots of zonal trip ends, prior to and post matrix estimation with regression statistics (slopes, intercepts and R2 values);

• trip length distributions, prior to and post matrix estimation, with means and standard deviations

• sector to sector level matrices, prior to and post matrix estimation, with absolute and percentage changes.

10.2 Trip Matrix Validation

Trip matrix validation will be measured by the comparison of observed and modelled flows across screenlines and cordons (which will be similar to those selected in the existing model).


11 Assignment Calibration and Validation Methodology

11.1 Assignment Calibration

The methodology proposed for the calibration of the network, routes and trip matrices has been described above. However, further steps can be taken to improve areas of weakness in the validation of these separate elements:

• the number of zone centroid connectors, their coded times and the points at which they connect to the network reconsidered and adjusted if necessary;

• flow bundle analysis used to understand routing and adjustments made to competing routes;

• modelled and surveyed journey times compared and analysed in order to identify queue locations and check outturn capacities on congested approaches and hence adjust signal timings, saturation flows, lane use, etc.; and

• ‘stress tests’ will be applied and the model response evaluated. The model will be “stressed” by increasing the trip demand in the matrices by 10% or 20%, or by the inclusion of new zones. This may reveal errors in the network which previous checks have not detected.

11.2 Assignment Validation

In addition to evidence of network, route and trip matrix validation, the Local Model Validation Report will include evidence of the validation of the assignment, in the following terms.

• Traffic flows on links - modelled flows and counts will compared per time period, for roadside interview survey screenlines, for screenlines used as constraints in matrix estimation and for screenlines used for independent validation. The measures, criteria and acceptability guidelines given in Table 3-B will be used.

• Journey times - modelled and surveyed journey times will be compared along routes, by time period. End to end route times will be analysed, with the means and 95% confidence intervals of observed times being presented alongside the modelled times. The measures, criteria and acceptability guidelines given in Table 3-C will be used.

• Turning movements at key junctions will be validated by time period. Because most available counts will be single day MCCs, turning movements may not validate to the standards achieved for link flows. Nevertheless, modelled turning flows and counts will be compared by time period and assessed using the link flow criteria and acceptability guidelines given in Table 3-B.


12 Summary of Model Development, Standards Proposed and Fitness for Purpose

12.1 Summary of Model Development

The 2013 AM and PM peak traffic models for Wycombe will be developed using PTV VISUM software, based on roadside interview data collected in May 2006 and highway assignment matrices development as part of 2006 CONTRAM models. The proposed methodology is described above. A Local Model Validation Report (LMVR) will be produced to document the methodology employed and the results of model validation, and will adhere to the advised structure and content as set out in the guidance in WebTAG unit 3.19.

12.2 Summary of Standards Proposed

As far as possible, given the constraints of programme and budget, the guidance set out in WebTAG Unit 3.19 and summarised in Section 3 of this report will be followed.

12.3 Proposed Assessment of Fitness for Purpose

The aim of the process set out in this report is to produce well validated models, with evidence of their fit to the 2013 traffic conditions and confidence in their application to forecast scenarios based on stress testing. Further evidence of the fitness for purpose will include validation of key junctions within the network area. The assessment of the application of 2006 RSI data to the models will be based on evidence of the changes in traffic between 2006 and 2013 at the RSI sites, and the changes applied to the 2006 matrices through matrix estimation.


Appendix A Current Local Model Validation Report

High Wycombe Transport Model - Local Model Validation Report (November 2011)

High Wycombe Transport Model Local Model Validation Report June 2012

Final

Document Control Sheet BPP 04 F8 Version 7 April 2011

Client: Transport for Buckinghamshire Project No: B1279860/TM01 Project: High Wycombe Transport Model Document Title: Local Model Validation Report Ref. No:

Originated by Checked by Reviewed by Approved by

NAME NAME NAME NAME ORIGINAL Dharmender Singh

Richard Verrall Anna Booth Richard Smith

DATE INITIALS DS INITIALS RV INITIALS AB INITIALS RS

19 Oct 2011 Draft

NAME NAME NAME NAME REVISION A Richard Verrall Hadley D-Lovett Richard Verrall Richard Smith

DATE INITIALS RV INITIALS HDL INITIALS RV INITIALS RS

11 Nov 2011 Final

NAME NAME NAME NAME REVISION B Dharmender Singh

Richard Verrall Richard Smith Richard Smith

DATE INITIALS DS INITIALS RV INITIALS RS INITIALS RS

19 Jun 2012 Final

NAME NAME NAME NAME REVISION

DATE INITIALS INITIALS INITIALS INITIALS

Document Status

NAME NAME NAME NAME REVISION

DATE INITIALS INITIALS INITIALS INITIALS

Document Status

Jacobs Engineering U.K. Limited This document has been prepared by a division, subsidiary or affiliate of Jacobs Engineering U.K. Limited (“Jacobs”) in its professional capacity as consultants in accordance with the terms and conditions of Jacobs’ contract with the commissioning party (the “Client”). Regard should be had to those terms and conditions when considering and/or placing any reliance on this document. No part of this document may be copied or reproduced by any means without prior written permission from Jacobs. If you have received this document in error, please destroy all copies in your possession or control and notify Jacobs. Any advice, opinions, or recommendations within this document (a) should be read and relied upon only in the context of the document as a whole; (b) do not, in any way, purport to include any manner of legal advice or opinion; (c) are based upon the information made available to Jacobs at the date of this document and on current UK standards, codes, technology and construction practices as at the date of this document. It should be noted and it is expressly stated that no independent verification of any of the documents or information supplied to Jacobs has been made. No liability is accepted by Jacobs for any use of this document, other than for the purposes for which it was originally prepared and provided. Following final delivery of this document to the Client, Jacobs will have no further obligations or duty to advise the Client on any matters, including development affecting the information or advice provided in this document. This document has been prepared for the exclusive use of the Client and unless otherwise agreed in writing by Jacobs, no other party may use, make use of or rely on the contents of this document. Should the Client wish to release this document to a third party, Jacobs may, at its discretion, agree to such release provided that (a) Jacobs’ written agreement is obtained prior to such release; and (b) by release of the document to the third party, that third party does not acquire any rights, contractual or otherwise, whatsoever against Jacobs and Jacobs, accordingly, assume no duties, liabilities or obligations to that third party; and (c) Jacobs accepts no responsibility for any loss or damage incurred by the Client or for any conflict of Jacobs’ interests arising out of the Client's release of this document to the third party.

Executive Summary

Transport for Buckinghamshire (TfB) commissioned Jacobs to update the 2006 CONTRAM highway assignment model for High Wycombe to a 2010 base year using the VISUM modelling software suite because of the need to reflect significant land use changes since 2006. The model is capable of assessing a range of scenarios including highway infrastructure and land-use changes. This report explains the steps taken to develop the model network and update the 2006 highway traffic matrices in order to calibrate to traffic surveys undertaken in 2010. The traffic surveys provided by TfB consist of manual classified counts of junction turning movements, automatic traffic counts and ANPR surveys. The 2006 matrices were updated by calibrating the modelled traffic to the 2010 AM and PM peak hour counts on a cordon and screenline basis. The model was calibrated and validated in line with DMRB guidance, and is considered to provide an accurate representation of traffic volumes and journey times. Overall, the AM and PM peak hour traffic models provide a suitable modelling platform for assessing the impact of highway and land-use changes in High Wycombe.

Contents

1 Introduction 1

1.1 Purpose of Report 1

1.2 Background 1

1.3 Study Area 1

1.4 Report Structure 2

2 Model Overview 3

2.1 History of the Wycombe Transport Model 3

2.2 Model Update Methodology 3

2.3 Model Description 3

3 Review of Existing Data 4

3.1 Introduction 4

3.2 WTS2 Data 4

3.3 Traffic Counts 4

3.4 2010 Journey Times 4

3.5 Land-use Changes between 2006 and 2010 7

4 Network Development 8

4.1 Introduction 8

4.2 Node and Link Data 8

4.2.1 Link Characteristics 9

4.2.2 Junction Characteristics 9

4.3 Zoning System 10

5 Matrix Development 12

5.1 CONTRAM 2006 Base Model 12

5.2 Matrix Estimation 12

5.2.1 Cordon and Screenline Adjustment 12

5.2.2 Trip Length Distribution Check 13

5.2.3 Matrix Adjustment Check 14

6 Assignment 15

6.1 Introduction 15

6.2 Assignment Convergence 15

7 Calibration and Validation 16

7.1 Calibration and Validation Criteria 16

7.1.1 Link Flow Criteria 16

7.1.2 Journey Time Criteria 16

7.2 Comparison of Calibration Flows 17

7.3 Link Flow Validation 18

7.4 Journey Time Validation 19

8 Summary 21

Table 2-A Characteristics of the High Wycombe Transport Model 3

Table 3-A Traffic Surveys used in the Model Development 6

Table 3-B Change in Land-Use 7

Table 6-A Convergence Criteria 15

Table 6-B Highway Assignment Analysis 15

Table 7-A Summary of Link Flow Calibration 17

Table 7-B AM Peak Cordon and Screenline Calibration 17

Table 7-C PM Peak Cordon and Screenline Calibration 18

Table 7-D Summary of Cordon and Screenline Calibration 18

Table 7-E AM & PM Peak Link Flow Validation 18

Table 7-F AM Peak Journey Time Validation 19

Table 7-G PM Peak Journey Time Validation 19

Figure 1-A 2010 Base Model Study Area 2

Figure 3-A Count Locations 5

Figure 3-B Journey Time Routes Surveyed 7

Figure 4-A Network Link Types 8

Figure 4-B Detailed Junction Coding in the Wycombe Transport Model 10

Figure 4-C Zone Plan for Wycombe Study Area 11

Figure 5-A Cordons and Screenlines 12

Figure 5-B AM Trip Length Distribution 13

Figure 5-C PM Trip Length Distribution 14

Appendix A Glossary of Commonly Used Terms

Appendix B Location of RSI Sites in 2006 Model Appendix C AM & PM Assignment - Traffic Volume Results

Appendix D AM & PM Calibration

Appendix E AM & PM Validation

Wycombe Transport Model - Local Model Validation Report_RevisionB_Final.doc

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1 Introduction

1.1 Purpose of Report

The Transport for Buckinghamshire (TfB) Alliance between Buckinghamshire County Council (BCC) and Ringway Jacobs was established to deliver all transportation services across the county. In March 2010 the findings of a Transportation Modelling Scoping Study were presented to the Alliance Strategic Board which outlined a strategy to develop a robust modelling platform with which to meet the future transport assessment needs of TfB. This Local Model Validation Report (LMVR) outlines the steps taken to update a 2006 base model of High Wycombe to 2010 and presents evidence in accordance with DMRB guidance which demonstrates that it is an accurate representation of existing traffic conditions.

1.2 Background

A 2006 base transport model for High Wycombe including demand, mode choice and assignment modelling was developed by Halcrow. The highway assignment element utilised the CONTRAM modelling package. Jacobs was commissioned to update the highway assignment model to a 2010 base year, with data from the CONTRAM model used as a foundation for the updated model. The 2010 base year model reflects updated traffic conditions providing a platform from which future traffic levels and patterns of movement can be assessed. A scoping exercise for the model update identified the VISUM software suite as a suitable replacement for CONTRAM that will meet the future assessment requirements of TfB. The key applications of the model are:

• To inform the assessment of highway infrastructure changes

• To assess the strategic impact of new land-use development proposals in the High Wycombe urban area

1.3 Study Area

High Wycombe is located in the Wycombe District of Buckinghamshire, with a current population of around 100,000. The town is situated north of the M40 motorway, at the hub of five radial highway corridors which include the A40 (east and west), A404 (north and south) and the A4128 Hughenden Road. The A4010, situated in the west of the town, provides a route for north – south movements towards Aylesbury. The 2010 transport model detailed study area includes the urban area of High Wycombe as shown in Figure 1-A. A wider buffer area with less detail is included which allows for route choice of traffic towards and away from the town.


2

Figure 1-A 2010 Base Model Study Area

1.4 Report Structure

Following the introduction, this report is structured as follows:

• Section 2 - provides an outline of the existing model and describes the steps taken to update the model to 2010

• Section 3 - describes the data used for model development, matrix building and model validation

• Section 4 - provides details of the development of the highway network

• Section 5 - provides details of the development of the assignment matrices

• Section 6 - provides details of the traffic assignment and model convergence

• Section 7 - provides details of the model calibration and validation processes and results

• Section 8 - presents the conclusions.

A glossary of terms used in this report is provided in Appendix A.

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Contains Ordnance Survey data © Crown copyright and database right 2011


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2 Model Overview

2.1 History of the Wycombe Transport Model

In 1992 Halcrow was appointed by BCC to develop a transport model of High Wycombe to assist in the development of a transport strategy as part of the Wycombe Transport Study (WTS). This model, known as WTS1, was developed using data collected in 1991 and 1992. In 2006, a new programme of data collection enabled a renewal of the model, referred to as WTS2. The WTS2 model has been used as the foundation for the development of the 2010 model.

2.2 Model Update Methodology

An outline of the model update methodology is given below. Further details of each stage are found in Sections 3, 4 and 5.

• Review of available traffic data

• Development of new highway network using GIS data

• Coding of junction details to reflect latest layouts and signal settings

• Extraction of matrices from WTS2 model

• Identification of data for use in calibration and validation

• Update of 2006 matrices to 2010 using calibration traffic data

• Validation of 2010 model using traffic counts and journey time data

2.3 Model Description

The 2010 Wycombe transport model has been developed using the VISUM software suite. The key characteristics of the transport model are summarised in Table 2-A below.

Since the model is intended to be used for assessing the traffic impact of highway schemes and new land-use development, Jacobs agreed with TfB to develop a highway assignment model. The selected time periods and the vehicle types included are those used in the 2006 model.

Key Characteristics High Wycombe 2010 Base

Model Structure Highway assignment model

Base Model Year 2010

Zoning System 205 zones (the CONTRAM model had 203 zones)

Time Periods AM Peak hour (08:00-09:00); PM Peak hour (17:00-18:00)

Model Area High Wycombe study area (see Figure 1-A), plus buffer network

Trip Matrices (Private Transport Modes)

Car matrix based on 2006 observed and synthesised trips combined

Light goods vehicles (LGV)

Heavy goods vehicles (HGV)

Trip Matrices (Public Transport Modes)

None (but software platform allows future inclusion of public transport)

Modelling Package VISUM 11.52

Calibration/Validation To comply with DMRB standards

Table 2-A Characteristics of the High Wycombe Transport Model


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3 Review of Existing Data

3.1 Introduction

Traffic count surveys from the previous Halcrow modelling work were available from TfB. The available surveys since 2006 were reviewed to assess what could be used to support the 2010 update and whether any additional data collection was required.

3.2 WTS2 Data

Jacobs received a range of datasets from TfB used to produce and update the WTS2 model, including the following:

• Roadside interview data (RSIs)

• Traffic count data - automatic traffic counts (ATCs) - manual classified counts (MCCs)

• Journey time data Full details of the WTS2 data sources are given in Chapter 3 of the Model Development Report1. The locations of the RSI sites used for the 2006 model are presented in Appendix B. These are included to demonstrate that the traffic surveys used in the 2010 update cover the locations of the RSI sites used for the development of the 2006 matrices. Therefore, using the 2006 matrices as the foundation for the model update is appropriate as the approach maintains the origin – destination (OD) data from the RSIs.

3.3 Traffic Counts

As part of the review of traffic and land-use data, TfB provided an inventory of all traffic count data available for 2010 which included MCC and ATC traffic counts. Further counts, which were conducted more recently to improve calibration, are assumed to be representative of 2010 conditions and can therefore be included in the calibration data. This assumption has been justified by a comparison of ATC data at the same location in 2010 and 2012 on the A40 London Road, which has shown no substantial change in peak traffic volumes. Figure 3-A presents the locations of all the traffic counts used in the calibration and validation of the 2010 base model. These locations are also listed in Table 3-A.

3.4 2010 Journey Times

The complete set of journey time routes extracted from ANPR surveys and used in the validation is presented in Figure 3-B. Further detail and the validation of the modelled journey times are presented in Section 7.4.

1 ‘Wycombe Transport Model Highway Model Development Report’ (Halcrow, October 2007)


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Figure 3-A Count Locations

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No. Location Details Weekday Date of Survey

Survey Type

Junction Type

1 A40 / A4010 West Wycombe: The Pedestal Roundabout

Tue 08/06/10 MCC Roundabout

2 Lane End Rd / Horns Lane Tue 22/06/10 MCC Priority

3 Cressex Rd / Horns Lane Tue 22/06/10 MCC Priority

4 Cressex Rd / Holmers Farm Way Fri 08/06/07 MCC Priority

5 New Rd / Lane End Rd Wed 16/06/10 MCC Roundabout

6 A4010 New Rd/Turnpike Rd Wed 12/03/08 MCC Priority

7 Cressex Rd / John Hall Way / New Rd Wed 12/03/08 MCC Roundabout

8 Mill End Rd / Dashwood Ave / Mill End Rd / Gallows Lane

Wed 09/06/10 MCC Priority

9 Plomer Hill/A40 West Wycombe Rd Weekday Average

Jun 10 ATC Link

10 Chalfont Way / A4010 John Hall Way / Holmers Farm Way

Wed 12/03/08 MCC Roundabout

11 Cressex Rd / Coronation Rd / Cressex Link Rd Wed 12/03/08 MCC Signal

12 Marlow Rd / Cressex Rd Tue 29/06/10 MCC Roundabout

13 M40 2 week

Midweek Average

Jun 10 TRADS Motorway

14 Desborough Rd / Deeds Grove Thu 04/03/10 MCC Priority

15 A404 Marlow Hill / Handy Cross Sports Centre Tue 22/06/10 MCC Signal

16 The Pastures / A40 West Wycombe Rd / Desborough Ave

Thu 24/06/10 MCC Signal

17 A404 Marlow Hill / Daws Hill Lane Tue 29/06/10 MCC Signal

18 Parker Knoll Way / entrance to Morrisons Wed 09/06/10 MCC Roundabout

19 A4128 Archway / A40 Abbey Way / A40 Oxford Rd Thu 24/06/10 MCC Roundabout

20 Hughenden Valley Rd / Cryers Hill Rd Tue 15/06/10 MCC Roundabout

21 Abbey Way Gyratory Thu 24/06/10 MCC Ring

22 Amersham Hill / Totteridge Rd Thu 17/06/10 MCC Priority

23 A404 Easton St Thu 24/09/10 MCC Ring

24 Four Ashes Rd / Kingshill Rd / North Rd Tue 15/06/10 MCC Priority

25 A404 Amersham Rd / Arnison Ave Fri 25/06/10 MCC Signal

26 Gordon Rd Weekday Average

Jun 10 ATC Link

27 A404 Amersham Rd / Totteridge Lane Thu 17/06/10 MCC Roundabout

28 Hatters Lane Weekday Average

Jun 10 ATC Link

29 Abbey Barn Rd / Kingsmead Rd / Abbey Barn Lane Wed 06/10/10 MCC Priority

30 Micklefield Rd / A40 London Rd Thu 17/06/10 MCC Signal

31 Cock Lane Weekday Average

Jun 10 ATC Link

32 Hazlemere Cross Rds Tue 29/06/10 MCC Roundabout

33 Hammersley Lane / A40 London Rd Tue 12/10/10 MCC Signal

34 Rayners Avenue Weekday Average

Jun 10 ATC Link

35 A4094 Knaves Beech Way / Boundary Rd Tue 25/05/10 MCC Roundabout

36 Hazlemere Rd / Elm Rd / New Rd / Common Wood Lane

Wed 06/10/10 MCC Priority

37 Tesco Access / London Rd / Knave’s Beech / A4094 Thu 22/03/12 MCC Roundabout

38 A40 London Rd/ Station Rd Thu 22/03/12 MCC Roundabout

39 Swains Lane / Treadaway Hill / Treadaway Rd Fri 18/06/10 MCC Priority

40 Heath End Rd / Swains Ln / Chapel Rd Thu 22/03/12 MCC Roundabout

Note 1: MCC Surveys are 0700 – 1900. ATC Surveys are 24hr.

Table 3-A Traffic Surveys used in the Model Development


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Figure 3-B Journey Time Routes Surveyed

3.5 Land-use Changes between 2006 and 2010

Land-use changes between 2006 and 2010 were identified in consultation with Wycombe District Council (WDC) and TfB. Significant changes in land-use are at the Eden Shopping Centre where an additional zone has been added to model the car park, and at the Wycombe Marsh development. The overall estimates of changes in residential land-use and employment are presented below in Table 3-B. These are extracted from data provided by TfB and interpolated to provide the estimates to 2010.

Development Type 2006 2010 % Change

Residential (no. of dwellings)

37078 38423 3.6

Employment (no. of jobs)

47909 48388 1.0

Table 3-B Change in Land-Use

The changes in land-use, other than those identified above, are spread through the town and individually are not substantial. These changes are accommodated in the model update through the process of calibrating the modelled traffic flows to 2010 count data.

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West Wycombe

Amersham Road Hughenden Valley Road

Handy Cross

London Road



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4 Network Development

4.1 Introduction

This section describes the development of the highway network for the 2010 model. The network data was derived from a variety of sources in order to represent the network elements with the best possible accuracy. The MeridianTM2 mid-scale vector dataset was used as the basis for building the model network. MeridianTM2 was deemed a suitable product due to ease of availability and high compatibility with VISUM. The MeridianTM2 Layer is in Geographic Information System (GIS) format which means that the resulting model network will be a geographically accurate representation of the actual road network, allowing results from the model to be overlaid on OS mapping. VISUM provides a direct interface with GIS-based datasets. Aerial photography and observations made on site visits were used to refine sections of the network and to code junction details. The resulting VISUM network is an accurate geographic representation of the road network, classified by link type into Motorways, A-roads, B-roads and local roads. The model highway network, with link type indicated by the colour, is presented in Figure 4-A.

Figure 4-A Network Link Types

4.2 Node and Link Data

The data for the model area was imported from the MeridianTM2 Layer into a VISUM file, which provided the model with link information, such as length, geometry and the road type (e.g. A-road, B-road, minor road). Each link and junction was assigned a model-specific reference number.

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The Meridian TM2 data is regularly updated by OS and so provides an up-to-date basis for the model development. Important changes to the network since 2006 include the Oxford Road / Archway junction with the Eden Car Park access, the Cressex Link Road between John Hall Way and Coronation Road, and the connection between Abbey Barn Road and London Road through the Wycombe Marsh development.

4.2.1 Link Characteristics

Additional characteristics were coded on to each link using aerial images, street level photographs and on-site observations. In VISUM links are coded by direction and the following characteristics are included:

• Number of lanes

• Link capacity (vehicles per hour)

• Maximum free-flow speed in kilometres per hour

• Class(es) of vehicles permitted to traverse the link (e.g. car, HGV, pedestrian, bus only)

• Traffic count(s) (for comparison with modelled flows). Link capacities were assigned based on a number of factors including link type, number of lanes, single or dual carriageway, street characteristics and amount of on-street parking. These factors and the speed limit pertaining to each link were used to determine the appropriate maximum free-flow speed. The resulting modelled speed on all links is dependant upon the volume of traffic using the link. Data that informs the setting of these parameters is given in DMRB Volume 5 Section 1 Part 32.

4.2.2 Junction Characteristics

Junction coding is an important part of the model development, as it is the delay encountered at roundabouts, signalised junctions and at side roads of give-way junctions which affects the impedance of a route and, therefore, the model assignment. Each junction is assigned a default geometry based on the number of arms (links) and the number of lanes. This basic geometry is refined by adding additional stopline lanes and flares (called ‘pockets’), using aerial photography and on-site observations. The traffic signal settings at signalised junctions were determined from configuration records provided by TfB where these were available, or from an appropriate assumed setup. The delays were balanced to prioritise the main road or principal movements. Pedestrian crossings have not been explicitly modelled, unless these are incorporated into signalised junctions and, therefore, included within the signal timings. The impact of other pedestrian crossings has been allowed for through the validation against journey times.

2 DMRB Volume 5 Section 1 Part 3 TA 79/99 Amendment No 1


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In the transport model the detailed evaluation of junction performance is enabled by Intersection Capacity Analysis (ICA), which encompasses procedures from the Highway Capacity Manual (HCM). These are similar to those used in the Transport Research Laboratory (TRL) junction analysis methods. The HCM contains guidelines for the calculation of junction level of service and performance for a wide range of control systems, from give-ways to roundabouts and signals, based on empirical data. VISUM uses the calculation steps within the HCM to calculate junction performance within a procedure called Intersection Capacity Analysis (ICA). During each iteration of an assignment, VISUM calculates the delay for each turn within a junction, based on the traffic volume, control system and opposing flows. The time taken to pass through the junction is combined with the link flow time to give the route impedance, which affects the assignment route choice on the successive iteration. A typical junction coding from the Wycombe Transport Model network is presented below in Figure 4-B.

Figure 4-B Detailed Junction Coding in the Wycombe Transport Model

4.3 Zoning System

The zoning system for the 2010 model is almost identical to that used for the 2006 WTS2 model. Two additional zones were inserted to include the Eden Shopping Centre Car Park and John Lewis in the south of the town. These were given an initial distribution from a nearby zone of a similar land-use, and the traffic volumes adjusted in the calibration process. There are 205 zones in the 2010 transport model, 93 of which are within the study area. In the model each zone centroid is connected to the highway network at one

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or more nodes by zone connectors. The nodes to which these connectors are joined were chosen to reflect the connectors in the 2006 WTS2 model and appropriate loading points in the network. The zone plan for the study area is presented in Figure 4-C .

Figure 4-C Zone Plan for Wycombe Study Area

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5 Matrix Development

5.1 CONTRAM 2006 Base Model

The CONTRAM 2006 base year highway assignment matrices were used as the source for origin – destination data in the model update. The 2006 matrices were originally developed from observed data (based on RSI surveys, LATS roadside interview data, ATC and MCC data), household survey and planning data, and from land-use trip rates and a gravity model for synthesised trips.

The 2006 model included separate OD matrices for cars, LGVs and HGVs.

5.2 Matrix Estimation

A comparison of traffic survey data from 2006 and 2010 indicated that there has not been uniform growth in traffic. It would, therefore, be inappropriate to estimate the 2010 matrix by application of a growth factor to the 2006 matrix. Instead, a methodology was followed to calibrate the 2006 matrix to 2010 counts by scaling the matrix on a cordon and screenline basis. 5.2.1 Cordon and Screenline Adjustment

The cordons and screenlines used in the model update are presented below in Figure 5-A.

Figure 5-A Cordons and Screenlines

The ‘flow-bundle’ function in VISUM (which is equivalent to the ‘select link’ function in software such as SATURN) was used to identify the OD routing of traffic through a link on a cordon or screenline. By comparing the modelled flow volume with the 2010 observed traffic volume, a ‘local’ growth factor was applied to the specific OD

Outer Cordon (green)

Railway screenline (red)

Inner Cordon (yellow)

North South Screenline (purple)

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South Wycombe Screenline (blue)


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movements through the link. The matrix was systematically adjusted across individual screenlines or cordons, maintaining the OD information within the 2006 RSI-based matrices. The LGV and HGV matrices were not updated; however, these vehicle types represent a small percentage of the overall traffic.

5.2.2 Trip Length Distribution Check

The trip length distributions for the AM and PM 2010 matrices were checked against the trip length distributions for the 2006 matrices. These are presented below in Figure 5-B and Figure 5-C, which show the number of trips in distance intervals of 0.5 km. Although there are a few points with substantial change, particularly at 2km and 19.5km in the AM peak, the overall pattern of high numbers of trips occurring at short distances and fewer trips occurring at longer distances has been maintained. Therefore, the figures indicate that the trip length distribution has not significantly changed in either peak hour model during the matrix update from 2006 to 2010.

0

200

400

600

800

1000

1200

1400

1600

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Journey Distance (km)

Nu

mb

er

of

Tri

ps

2006 AM

2010 AM

Figure 5-B AM Trip Length Distribution


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0

200

400

600

800

1000

1200

1400

1600

1800

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Journey Distance (km)

Nu

mb

er

of

Tri

ps

2006 PM

2010 PM

Figure 5-C PM Trip Length Distribution

5.2.3 Matrix Adjustment Check

In addition to checking the trip length distribution, the patterns of movement across the study area were checked by a sector matrix analysis. This grouped the zones into regions of the study area and wider area, and compared the original 2006 sector matrices with the 2010 sector matrices. This indicated that the matrix update process did not significantly change the overall pattern of movement, and therefore provides further confirmation that the matrix update did not alter the OD information contained within the 2006 matrices.


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6 Assignment

6.1 Introduction

The assignment procedure adopted for the highway model is based on an equilibrium assignment with multiple demand segments (Car/LGV and HGV). The assignment process ends when a satisfactory level of convergence is achieved. The traffic flow results of the highway assignment are presented in Appendix C.

6.2 Assignment Convergence

The assignment was set to run for a maximum of 50 iterations and, in both the AM and PM models, the assignment achieved the convergence criteria in less than 50 iterations. The DMRB guidance is to check the percentage change in link flows over successive iterations; however, VISUM provides the GEH of the change in turning flows over successive iterations, which will provide a similar indication of convergence. The convergence criteria used are presented in Table 6-A below.

Comparison with Previous Iteration

Required Criteria for Convergence

% Turning Movements with GEH > 1 < 5%

Gap (difference in journey costs) < 0.0001

Table 6-A Convergence Criteria

Details of the highway assignment convergence are summarised in Table 6-B below.

Criteria Iteration

AM Model 8 9 10 11 12

% of turns with Volume GEH >1

12.8 9.0 7.3 5.9 4.6

Gap 0.00003171 0.00004928 0.00004940 0.00001655 0.00002079

PM Model 7 8 9 10 11

% of turns with Volume GEH >1

16.9 11.4 8.5 6.0 4.0

Gap 0.00003349 0.00000987 0.00003254 0.00002456 0.00000754

Table 6-B Highway Assignment Analysis

This table demonstrates that the AM and PM models achieved a good level of convergence in accordance with DMRB standards.


16

7 Calibration and Validation

7.1 Calibration and Validation Criteria

After the development of the highway network and matrices, the traffic assignment was assessed against observed traffic flow and journey time data. The Department for Transport sets various criteria to be met before a transport model can be said to be representing base year conditions to an acceptable standard. These criteria are set out in the DMRB and comprise:

• Good comparison between observed and modelled flow volumes on screenlines across the study area

• Good comparison between observed and modelled journey times through the study area.

Modelled flows were calibrated to observed data forming cordons and screenlines in High Wycombe and validated against an independent set of count data. For validation, a number of journey times were extracted from 2010 ANPR surveys. The journey time data represented nine major routes through the town. 7.1.1 Link Flow Criteria

Over 85% of flow volume comparisons are required to have a GEH value of less than 5.0 for individual flows and screenline totals should have a GEH of less than 4.0 for all or nearly all screenlines. The GEH value is a form of the CHI-squared statistic and shows the goodness of fit between modelled and observed data. It is defined as:

Where M is the modelled flow and C is the observed flow.

At least 85% of modelled flows should also meet the following requirements.

• Individual flows within 15% for flows of 700-2700 vehicles per hour (vph)

• Individual flows within 100 vph for flows <700 vph

• Individual flows within 400 vph for flows >2700 vph Screenline totals should be within 5% of observed traffic volumes for all or nearly all screenlines. 7.1.2 Journey Time Criteria

The journey time validation was based on the DMRB criteria which requires the difference between the modelled and observed journey times to be within 15% (or 1 minute, if higher than 15% of the observed journey time) for at least 85% of routes tested.

( )

+

−

=

2

2

CM

CM

GEH


17

7.2 Comparison of Calibration Flows

A summary of the calibration results for the link flows which form the cordons and screenlines, and the degree to which the criteria were achieved are presented in Table 7-A. AM Peak PM Peak

No. of Link Flow Comparisons 84 84

% Link Flows GEH < 5 89 83

% of Modelled Flows Criterion 86 80

Table 7-A Summary of Link Flow Calibration

Whilst the calibration result for PM is marginally less than the 85% threshold described in DMRB guidance, if the percentage of links at a GEH of less than 6 were considered, then the AM and PM peak models would pass at 94% and 88% respectively. Overall, the link flow calibration results provide confidence that the model is closely replicating the observed traffic volumes. Table 7-B and Table 7-C present a comparison of the cordon and screenline totals with the observed counts for the AM and PM peak hours. The results of the comparison between observed and modelled flows at each individual site of the cordons and screenlines are presented in Appendix D.

Cordon / Screenline

Dir. Observed

(no. of vehicles)

Modelled (no. of

vehicles)

Difference (Mod-Obs)

% Difference

GEH Criteria GEH <5

Criteria Flow

Outer Cordon (Green)

In 9792 9483 -309 -3.2 3.1 Pass Pass


Out 9937 9885 -52 -0.5 0.5 Pass Pass

Inner Cordon (Yellow)

In 5912 5862 -50 -0.8 0.7 Pass Pass


Out 4920 4913 -7 -0.1 0.1 Pass Pass

Railway (Red) S 6452 6567 115 1.8 1.4 Pass Pass

Railway (Red) N 3366 3346 -20 -0.6 0.3 Pass Pass

South Wycombe(Blue)

N 5919 5693 -226 -3.8 3 Pass Pass

South Wycombe(Blue)

S 6992 6974 -18 -0.3 0.2 Pass Pass

North-South (Purple)

W 3845 3624 -221 -5.7 3.6 Pass Fail


E 3861 3679 -182 -4.7 3 Pass Pass

Table 7-B AM Peak Cordon and Screenline Calibration


18

Cordon / Screenline

Dir. Observed

(no. of vehicles)

Modelled (no. of

vehicles)


% Difference

GEH Criteria GEH <5

Criteria Flow


In 9482 9588 106 1.1 1.1 Pass Pass


Out 10322 10685 363 3.5 3.5 Pass Pass


In 4880 4968 88 1.8 1.3 Pass Pass


Out 5683 5700 17 0.3 0.2 Pass Pass

Railway (Red) S 3733 3649 -84 -2.3 1.4 Pass Pass

Railway (Red) N 5943 5782 -161 -2.7 2.1 Pass Pass

South Wycombe(Blue)

N 6998 6871 -127 -1.8 1.5 Pass Pass

South Wycombe(Blue)

S 6106 5728 -378 -6.2 4.9 Fail Fail


W 3673 3582 -91 -2.5 1.5 Pass Pass


E 3804 3915 111 2.9 1.8 Pass Pass

Table 7-C PM Peak Cordon and Screenline Calibration

Table 7-D presents a summary of the cordon and screenline calibration, which shows a good calibration to the observed volumes. DMRB guidance is for all, or nearly all of comparisons to have a GEH of less than 4 and be within 5% of the observed volume. AM Peak PM Peak

No. of cordon / screenline comparisons 10 10

% GEH < 4 100 90

% of acceptable totals 90 90

Table 7-D Summary of Cordon and Screenline Calibration

Both the AM peak and PM peak satisfy the DMRB guidance well. Therefore, the cordon and screenline calibration results, together with the individual link flow results, provide confidence that the observed traffic volumes are well reflected in the model.

7.3 Link Flow Validation

The comparison of the link flows for validation is presented in Appendix E, and is summarised below in Table 7-E. AM Peak PM Peak

No. of link flow comparisons 121 121

% Link Flows GEH < 5 79 87

% of modelled flows criterion 73 80

Table 7-E AM & PM Peak Link Flow Validation

The results show a good validation of the link flows in the PM Peak. Although the DMRB guidance criteria of 85% link flows passing is not met in the AM Peak, a large proportion of the links that fail do so marginally. If comparing with a GEH of 7 instead of 5, the AM model would validate at 91%. In light of the very high level of calibration of the base model, it is considered that the model demonstrates acceptable validation to the observed flows.


19

7.4 Journey Time Validation

Journey time validation was undertaken as supplementary to the link flow validation of the base 2010 AM and PM peak models. The journey time routes (presented in Figure 3-B) extend across key routes in, through and out of the town. The observed data from the routes was derived from ANPR surveys. The journey time validation results are presented in Table 7-F and Table 7-G

Route Direction Observed

Mean (mm:ss)

Modelled (mm:ss)

% Difference

1 Handy X to West Wycombe 08:59 11:04 23.2 Fail

2 Handy X to Hughenden Valley Road 11:19 10:17 -9.1 Pass

3 Handy X to Amersham Road clockwise 12:51 12:03 -6.2 Pass

4 Handy X to Amersham Road anticlockwise 12:51 11:53 -7.5 Pass

5 Handy X to London Road 17:19 15:38 -9.7 Pass

6 West Wycombe to Handy X 10:16 08:39 -15.8 Fail

7 London Road to Hughenden Valley Road 19:49 18:15 -7.9 Pass

8 London Road to Handy X 17:00 14:27 -15 Pass

9 Amersham Road to Handy X 15:03 13:00 -13.7 Pass

10 Hughenden Valley Road to Handy X 13:32 14:16 5.4 Pass

11 Hughenden Valley Road to London Road 22:30 22:10 -1.5 Pass

12 West Wycombe to Amersham Road 19:28 16:51 -13.4 Pass

13 West Wycombe to Hughenden Valley Road 15:40 12:10 -22.4 Fail

14 West Wycombe to London Road 24:00 21:14 -11.6 Pass

15 London Road to West Wycombe 19:07 19:41 3 Pass

16 Amersham Road to West Wycombe 14:57 18:13 21.9 Fail

17 Hughenden Valley Road to West Wycombe 13:14 14:51 12.2 Pass

Table 7-F AM Peak Journey Time Validation

Route Direction Observed

Mean (mm:ss)

Modelled (mm:ss)

% Difference

1 Handy X to West Wycombe 12:20 12:10 -1.3 Pass

2 Handy X to Hughenden Valley Road 11:56 15:15 27.8 Fail

3 Handy X to Amersham Road clockwise 14:45 13:08 -11.0 Pass

4 Handy X to Amersham Road anticlockwise 14:45 13:05 -11.3 Pass

5 Handy X to London Road 17:09 14:52 -13.3 Pass

6 West Wycombe to Handy X 12:16 09:11 -25.2 Fail

7 London Road to Hughenden Valley Road 21:27 23:27 9.3 Pass

8 London Road to Handy X 18:47 15:19 -18.5 Fail

9 Amersham Road to Handy X 11:22 12:52 13.2 Pass

10 Hughenden Valley Road to Handy X 09:54 10:20 4.3 Pass

11 Hughenden Valley Road to London Road 19:28 17:31 -10.0 Pass

12 West Wycombe to Amersham Road 18:23 16:35 -9.8 Pass

13 West Wycombe to Hughenden Valley Road 12:38 14:01 10.9 Pass

14 West Wycombe to London Road 21:40 19:12 -11.4 Pass

15 London Road to West Wycombe 25:58 21:00 -19.2 Fail

16 Amersham Road to West Wycombe 18:20 18:33 1.2 Pass

17 Hughenden Valley Road to West Wycombe 13:42 11:43 -14.5 Pass

Table 7-G PM Peak Journey Time Validation


20

This comparison shows a good level of fit between observed and modelled journey times. However, the journey time validation does not meet the DMRB guidance in either the AM or PM peak. In both the AM peak and PM Peak, 76% of the journey times pass the DMRB criteria. The results show that, overall, the model reasonably represents the journey times in High Wycombe.


21

8 Summary

The Wycombe Transport Model has been updated from the 2006 CONTRAM model to a 2010 base year using VISUM software. The model includes the urban area and a representation of regional urban centres. The model has been developed to assess typical weekday morning and evening peak hour conditions. The model is a tool which can be used to assess the highway impact of new developments in and around High Wycombe, and the impact of transport schemes and other changes in land-use upon the traffic in the town. The model has been developed using the 2006 CONTRAM matrices as a basis for the origin-destination data. These matrices were updated to a 2010 base year by calibrating the modelled flows to 2010 traffic surveys. The traffic volume data was supplemented by journey time data across key routes through the town. The model has been calibrated according to DMRB guidance to ensure its suitability for use. The model has been successfully validated against observed traffic volumes and supplemented by journey time data comparisons which together provide comprehensive coverage across the complex network. The transport model is deemed to provide a robust platform for traffic forecasting and scheme assessment within the model study area.


Appendix A Glossary of Commonly Used Terms

Acronym Definition

ANPR Automatic Number Plate Recognition

ATC Automatic Traffic Count (using road-surface sensors)

BCC Buckinghamshire County Council

CONTRAM CONtinuous TRaffic Assignment Model (transport modelling software developed by TRL Ltd. & Mott MacDonald)

DfT Department for Transport

DMRB Design Manual for Roads and Bridges

GEH A statistic measuring how well model volumes compare with survey volumes

GIS Geographic Information System

Halcrow Halcrow Group Limited

HCM Highway Capacity Manual

HGV Heavy Goods Vehicle

ICA Intersection Capacity Analysis

Jacobs Jacobs Engineering UK Limited

LGV Light Goods Vehicle

LMVR Local Model Validation Report

MCC Manual Classified Traffic Count (often using video technology)

Meridian™2 GIS database of roads from Ordnance Survey

OD Origin to Destination

RSI Roadside Interview survey

TfB Transport for Buckinghamshire Alliance (between BCC and Ringway Jacobs)

TRL The UK’s Transport Research Laboratory

VISUM Macro Transport Modelling software developed by PTV AG

VPH Vehicles per Hour

WTS Wycombe Transport Study


Appendix B Location of RSI Sites in 2006 Model

N



Appendix C AM & PM Assignment - Traffic Volume Results

N



N



Appendix D AM & PM Calibration

AM Calibration Table

Group Name

Dir. Link Name Observed

(no. of vehicles)

Modelled (no. of

vehicles)


% Difference

GEH Criteria GEH <5

Criteria GEH <10

Criteria Flow

Valley Road 768 794 26 3.4 0.9 Pass Pass Pass

Kingshill Road 725 467 -258 -35.6 10.6 Fail Fail Fail

Amersham Road 748 583 -165 -22.1 6.4 Fail Pass Fail

Holmer Green Road 463 548 85 18.4 3.8 Pass Pass Pass

Common Wood Lane 224 182 -42 -18.8 2.9 Pass Pass Pass

Penn Road 304 280 -24 -7.9 1.4 Pass Pass Pass

Rayners Avenue 50 88 38 76 4.6 Pass Pass Pass

London Road 781 788 7 0.9 0.2 Pass Pass Pass

Kingsmead Road 187 210 23 12.3 1.6 Pass Pass Pass

Abbey Barn Lane 202 123 -79 -39.1 6.2 Fail Pass Pass

Daws Hill Lane 666 660 -6 -0.9 0.2 Pass Pass Pass

Marlow Hill 1014 1128 114 11.2 3.5 Pass Pass Pass

Marlow Road 712 756 44 6.2 1.6 Pass Pass Pass

John Hall Way 1033 997 -36 -3.5 1.1 Pass Pass Pass

Cressex Road 568 521 -47 -8.3 2 Pass Pass Pass

Lane End Road 320 245 -75 -23.4 4.5 Pass Pass Pass

Inb

ou

nd

West Wycombe Road 1027 1113 86 8.4 2.6 Pass Pass Pass

Screenline Total 9792 9483 -309 -3.2 3.1 Pass Pass Pass


Kingshill Road 661 493 -168 -25.4 7 Fail Pass Fail

Amersham Road 509 437 -72 -14.1 3.3 Pass Pass Pass

Holmer Green Road 328 306 -22 -6.7 1.2 Pass Pass Pass

Common Wood Lane 258 191 -67 -26 4.5 Pass Pass Pass

Penn Road 707 581 -126 -17.8 5 Fail Pass Fail


London Road 842 991 149 17.7 4.9 Pass Pass Fail

Kingsmead Road 484 437 -47 -9.7 2.2 Pass Pass Pass

Abbey Barn Lane 417 311 -106 -25.4 5.6 Fail Pass Fail




John Hall Way 619 650 31 5 1.2 Pass Pass Pass

Cressex Road 451 457 6 1.3 0.3 Pass Pass Pass

Lane End Road 172 203 31 18 2.3 Pass Pass Pass

Ou

ter

Co

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(Gre

en

)

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Crendon Street 749 814 65 8.7 2.3 Pass Pass Pass

London Road 1274 1136 -138 -10.8 4 Pass Pass Pass

Marlow Hill 1293 1508 215 16.6 5.7 Fail Pass Fail

Queen Alexandra Road 490 506 16 3.3 0.7 Pass Pass Pass

Oxford Road 737 643 -94 -12.8 3.6 Pass Pass Pass Inb

ou

nd

Archway 1369 1255 -114 -8.3 3.1 Pass Pass Pass



London Road 1156 1077 -79 -6.8 2.4 Pass Pass Pass


Queen Alexandra Road 755 800 45 6 1.6 Pass Pass Pass

Oxford Road 562 486 -76 -13.5 3.3 Pass Pass Pass

Inn

er

Co

rdo

n

(Yell

ow

)

Ou

tbo

un

d

Archway 396 439 43 10.9 2.1 Pass Pass Pass


Plomer Hill 653 723 64 9.7 2.4 Pass Pass Pass

The Pastures 709 668 -41 -5.8 1.6 Pass Pass Pass

Bellfield Road 549 474 -75 -13.7 3.3 Pass Pass Pass

Archway 1369 1255 -114 -8.3 3.1 Pass Pass Pass


Gordon Road 595 604 9 1.5 0.4 Pass Pass Pass

Hatter's Lane 430 449 19 4.4 0.9 Pass Pass Pass

Micklefield Road 452 502 50 11.1 2.3 Pass Pass Pass

Cock Lane 139 165 26 18.7 2.1 Pass Pass Pass

Hammersley Lane 481 545 64 13.3 2.8 Pass Pass Pass

So

uth

bo

un

d


Screenline Total 6446 6567 115 1.8 1.4 Pass Pass Pass

Plomer Hill 340 310 -60 -16.2 3.3 Pass Pass Pass

The Pastures 295 358 63 21.4 3.5 Pass Pass Pass




Gordon Road 282 342 60 21.3 3.4 Pass Pass Pass

Hatter's Lane 291 251 -40 -13.7 2.4 Pass Pass Pass

Micklefield Road 244 243 -1 -0.4 0.1 Pass Pass Pass

Cock Lane 270 194 -76 -28.1 5 Fail Pass Pass

Hammersley Lane 169 120 -49 -29 4.1 Pass Pass Pass

Rail

way S

cre

en

lin

e

(Red

)

No

rth

bo

un

d



Horns Lane 254 186 -68 -26.8 4.6 Pass Pass Fail

New Road 745 744 -1 -0.1 0 Pass Pass Pass

Desborough Avenue 773 827 54 7 1.9 Pass Pass Pass


Abbey Barn Lane(SW) 202 123 -79 -39.1 6.2 Fail Pass Fail

Treadaway Hill 642 534 -108 -16.8 4.5 Pass Pass Fail

Boundary Road 510 391 -119 -23.3 5.6 Fail Pass Fail

M40 Off Slip 875 858 -17 -1.9 0.6 Pass Pass Pass

No

rth

bo

un

d

A40 Knaves Beech 625 522 -103 -16.5 4.3 Pass Pass Fail

Screenline Total 5919 5693 -226 -3.8 3 Pass Pass Pass

Horns Lane 399 173 -226 -56.6 13.4 Fail Pass Fail

New Road 1091 1036 -55 -5 1.7 Pass Pass Pass

Desborough Avenue 866 914 48 5.5 1.6 Pass Pass Pass



Treadaway Hill 622 754 132 21.2 5 Fail Pass Fail

Boundary Road 503 502 -1 -0.2 0 Pass Pass Pass

M40 Off Slip 970 1057 87 9 2.7 Pass Pass Pass

So

uth

Wyco

mb

e S

cre

en

lin

e (

Blu

e)

So

uth

bo

un

d

A40 Knaves Beech 630 726 96 15.2 3.7 Pass Pass Pass



Penn Road 708 644 -64 -9 2.5 Pass Pass Pass Totteridge Lane 637 650 13 2 0.5 Pass Pass Pass

Arnison Avenue 252 205 -47 -18.7 3.1 Pass Pass Pass

Totteridge Road 308 329 21 6.8 1.2 Pass Pass Pass

London Road 1274 1136 -138 -10.8 4 Pass Pass Pass

Westb

ou

nd


Screenline Total 3845 3624 -221 -5.7 3.6 Pass Pass Fail


Totteridge Lane 473 465 -8 -1.7 0.4 Pass Pass Pass

Arnison Avenue 201 223 22 10.9 1.5 Pass Pass Pass



East-

West

Scre

en

lin

e

(Pu

rple

)

Eastb

ou

nd


Screenline Total 3861 3679 -182 -4.7 3 Pass Pass Pass

PM Calibration Table

Group Name

Dir. Link Name Observed

(no. of vehicles)

Modelled (no. of

vehicles)


% Difference

GEH Criteria GEH <5

Criteria GEH <10

Criteria Flow


Kingshill Road 357 301 -56 -15.7 3.1 Pass Pass Pass

Amersham Road 514 560 46 8.9 2 Pass Pass Pass

Holmer Green Road 660 560 -100 -15.2 4 Pass Pass Pass

Common Wood Lane 60 132 72 120 7.3 Fail Pass Pass


Rayners Avenue 170 137 -33 -19.4 2.7 Pass Pass Pass

London Road 1014 1136 122 12 3.7 Pass Pass Pass

Kingsmead Road 416 369 -47 -11.3 2.4 Pass Pass Pass

Abbey Barn Lane 429 306 -123 -28.7 6.4 Fail Pass Fail

Daws Hill Lane 556 558 2 0.4 0.1 Pass Pass Pass

Marlow Hill 1062 1200 138 13 4.1 Pass Pass Pass


John Hall Way 796 751 -45 -5.7 1.6 Pass Pass Pass

Cressex Road 439 422 -17 -3.9 0.8 Pass Pass Pass

Lane End Road 137 140 3 2.2 0.3 Pass Pass Pass

Inb

ou

nd

West Wycombe Road 903 1053 150 16.6 4.8 Pass Pass Fail


Valley Road 914 1114 200 21.9 6.3 Fail Pass Fail

Kingshill Road 604 471 -133 -22 5.7 Fail Pass Fail

Amersham Road 738 750 12 1.6 0.4 Pass Pass Pass

Holmer Green Road 531 467 -64 -12.1 2.9 Pass Pass Pass

Common Wood Lane 93 99 6 6.5 0.6 Pass Pass Pass

Penn Road 279 320 41 14.7 2.4 Pass Pass Pass

Rayners Avenue 89 141 52 58.4 4.8 Pass Pass Pass


Kingsmead Road 183 238 55 30.1 3.8 Pass Pass Pass

Abbey Barn Lane 240 177 -63 -26.3 4.4 Pass Pass Pass


Marlow Hill 1205 1482 277 23 7.6 Fail Pass Fail

Marlow Road 754 689 -65 -8.6 2.4 Pass Pass Pass

John Hall Way 1078 1235 157 14.6 4.6 Pass Pass Pass

Cressex Road 455 421 -34 -7.5 1.6 Pass Pass Pass

Lane End Road 337 180 -157 -46.6 9.8 Fail Pass Fail

Ou

ter

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n

(Gre

en

)

Ou

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d



Crendon Street 627 524 -103 -16.4 4.3 Pass Pass Fail



Queen Alexandra Road 527 448 -79 -15 3.6 Pass Pass Pass

Oxford Road 759 800 41 5.4 1.5 Pass Pass Pass Inb

ou

nd





Marlow Hill 1830 1654 -176 -9.6 4.2 Pass Pass Pass

Queen Alexandra Road 449 513 64 14.3 2.9 Pass Pass Pass

Oxford Road 609 523 -86 -14.1 3.6 Pass Pass Pass

Inn

er

Co

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n

(Yell

ow

)

Ou

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d



Plomer Hill 420 423 3 0.7 0.1 Pass Pass Pass

The Pastures 302 351 49 16.2 2.7 Pass Pass Pass

Bellfield Road 416 387 -29 -7 1.4 Pass Pass Pass


Crendon Street 627 524 -103 -16.4 4.3 Pass Pass Fail

Gordon Road 388 370 -18 -4.6 0.9 Pass Pass Pass

Hatter's Lane 275 258 -17 -6.2 1 Pass Pass Pass

Micklefield Road 314 337 23 7.3 1.3 Pass Pass Pass

Cock Lane 228 151 -77 -33.8 5.6 Fail Pass Pass

Hammersley Lane 164 190 26 15.9 2 Pass Pass Pass

So

uth

bo

un

d

Rayners Avenue 89 141 52 58.4 4.8 Pass Pass Pass


Plomer Hill 650 569 -81 -12.5 3.3 Pass Pass Pass

The Pastures 659 758 99 15 3.7 Pass Pass Pass




Gordon Road 453 280 -173 -38.2 9 Fail Pass Fail

Hatter's Lane 499 378 -121 -24.2 5.8 Fail Pass Fail

Micklefield Road 528 442 -86 -16.3 3.9 Pass Pass Pass

Cock Lane 141 238 97 68.8 7 Fail Pass Pass

Hammersley Lane 393 395 2 0.5 0.1 Pass Pass Pass

Rail

way S

cre

en

lin

e

(Red

)

No

rth

bo

un

d

Rayners Avenue 170 137 -33 -19.4 2.7 Pass Pass Pass


Criteria GEH <4

Criteria GEH <5

Criteria Flow

Pass 10 10 9

Fail 0 0 1

Total 10 10 10

Cordon / Screenline

Totals % 100 100 90

Criteria GEH <5

Criteria GEH <10

Criteria Flow

Pass 75 82 72

Fail 9 2 12

Total 84 84 84

Individual Link Flows

% 89 98 86


Horns Lane 317 202 -115 -36.3 7.1 Fail Pass Fail New Road 1155 1097 -58 -5 1.7 Pass Pass Pass

Desborough Avenue 950 1076 126 13.3 4 Pass Pass Pass



Treadaway Hill 629 668 39 6.2 1.5 Pass Pass Pass

Boundary Road 482 379 -103 -21.4 5 Fail Pass Fail

M40 Off Slip 1017 871 -146 -14.4 4.8 Pass Pass Pass N

ort

hb

ou

nd

A40 Knaves Beech 696 672 -24 -3.4 0.9 Pass Pass Pass


Horns Lane 225 189 -36 -16 2.5 Pass Pass Pass

New Road 802 807 5 0.6 0.2 Pass Pass Pass

Desborough Avenue 628 712 84 13.4 3.2 Pass Pass Pass

Marlow Hill 1830 1654 -176 -9.6 4.2 Pass Pass Pass

Abbey Barn Lane(SW) 240 177 -63 -26.3 4.4 Pass Pass Pass

Treadaway Hill 649 771 122 18.8 4.6 Pass Pass Fail

Boundary Road 451 335 -116 -25.7 5.9 Fail Pass Fail

M40 Off Slip 756 597 -159 -21 6.1 Fail Pass Fail

So

uth

Wyco

mb

e S

cre

en

lin

e (

Blu

e)

So

uth

bo

un

d

A40 Knaves Beech 525 486 -39 -7.4 1.7 Pass Pass Pass

Screenline Total 6106 5728 -378 -6.2 4.9 Fail Pass Fail


Totteridge Lane 557 672 115 20.6 4.6 Pass Pass Fail


Totteridge Road 273 215 -58 -21.2 3.7 Pass Pass Pass


Westb

ou

nd



Penn Road 857 874 17 2 0.6 Pass Pass Pass

Totteridge Lane 586 626 40 6.8 1.6 Pass Pass Pass




East-

West

Scre

en

lin

e

(Pu

rple

)

Eastb

ou

nd



Criteria GEH <4

Criteria GEH <5

Criteria Flow

Pass 9 10 9

Fail 1 0 1

Total 10 10 10

Cordon / Screenline

Totals % 90 100 90

Criteria GEH <5

Criteria GEH <10

Criteria Flow

Pass 70 84 67

Fail 14 0 17

Total 84 84 84 Individual Link

Flows

% 83 100 80


Appendix E AM & PM Validation

AM Validation Table

Link No.

Location/Movement Observed

(no. of vehicles)

Modelled (no. of

vehicles)


% Difference

GEH Criteria GEH <5

Criteria GEH <10

Criteria Flow

1 A4010 New Road NB Towards Junction with Land End Rd 557 634 77 13.8 3.2 Pass Pass Pass

2 A4010 New Road SB Away from with Lands End Rd 497 745 248 49.9 10 Fail Fail Fail

3 A40 West Wycombe Rd WB Towards Junction with Plomer Hill 674 752 78 11.6 2.9 Pass Pass Pass

4 A40 West Wycombe Rd EB Away from Junction with Plomer Hill 889 999 110 12.3 3.6 Pass Pass Pass

5 A40 West Wycombe Rd WB Away from Junction with Plomer Hill 763 732 -31 -4.1 1.1 Pass Pass Pass

6 A40 West Wycombe Rd EB Towards Junction with Plomer Hill 689 566 -123 -17.9 4.9 Pass Pass Fail

7 A40 West Wycombe Way West WB Away from Junction with Desborough Ave 667 707 40 6 1.5 Pass Pass Pass

8 A40 West Wycombe Way West EB Towards Junction with Desborough Ave 679 657 -22 -3.3 0.9 Pass Pass Pass

9 A404 Amersham Road SB Towards Junction with Totteridge Ln 1061 834 -227 -21.4 7.4 Fail Pass Fail

10 A404 Amersham Road NB Away from Junction with Totteridge Ln 879 831 -48 -5.5 1.7 Pass Pass Pass

11 A404 Crendon Street SB Toward Junction with Totteridge Rd 557 641 84 15 3.4 Pass Pass Pass

12 A404 Crendon Street NB Away from Junction with Totteridge Rd 424 489 65 15.4 3 Pass Pass Pass

13 A404 Amersham Road SB Towards Junction with Green St 873 751 -122 -13.9 4.3 Pass Pass Pass

14 A404 Amersham Road NB Away from Junction with Green St 870 721 -149 -17.2 5.3 Fail Pass Fail

15 A404 Amersham Road SB Towards Junction with Hamilton Rd 775 845 70 9 2.5 Pass Pass Pass

16 A404 Amersham Road NB Away from Junction with Hamilton Rd 517 632 115 22.3 4.8 Pass Pass Fail

17 A40 London Road WB Towards Junction with Gomm Rd 803 877 74 9.3 2.6 Pass Pass Pass

18 A40 London Road EB Away from Junction with Gomm Rd 552 655 103 18.7 4.2 Pass Pass Fail

19 A404 Easton Street SB Towards Junction with A40 Abbey Way 716 850 134 18.7 4.8 Pass Pass Fail

20 A4010 New Rd SB Towards Junction with Lane End Rd 1273 1205 -68 -5.3 1.9 Pass Pass Pass

21 A4010 New Rd NB Away from Junction with Lane End Rd 926 1067 141 15.3 4.5 Pass Pass Fail

22 A4010 John Hall Way NB Towards Junction with Cressex Rd 531 423 -108 -20.3 4.9 Pass Pass Fail

23 A4010 John Hall Way SB Away from Junction with Cressex Rd 581 485 -96 -16.4 4.1 Pass Pass Pass

24 A4010 New Rd NB Towards Junction with Turnpike Rd 833 754 -79 -9.5 2.8 Pass Pass Pass

25 A4010 New Rd SB Away from Junction with Turnpike Rd 800 801 1 0.1 0 Pass Pass Pass

26 A40 Abbey Way West Away from Abbey Way Gyratory 959 1002 43 4.4 1.4 Pass Pass Pass

27 A40 Abbey Way West towards Abbey Way Gyratory 1268 1136 -132 -10.4 3.8 Pass Pass Pass

28 A40 Abbey Way NB Away from Junction with Lilys Walk 740 740 0 -0.1 0 Pass Pass Pass

29 A40 Abbey Way WB Towards Roundabout 1990 1986 -4 -0.2 0.1 Pass Pass Pass

30 A40 Abbey Way EB Away from Roundabout 756 847 91 12 3.2 Pass Pass Pass

31 A404 Amersham Rd SB Towards Junction with Amison Ave 814 876 62 7.6 2.1 Pass Pass Pass

32 A404 Amersham Rd NB Away from Junction with Amison Ave 607 644 37 6.1 1.5 Pass Pass Pass

33 A404 Amersham Road South Westbound between Totteridge Ln and Kingshill Rd 1192 987 -205 -17.2 6.2 Fail Pass Fail

34 A404 Amersham Road North East bound between Totteridge Ln and Kingshill Rd 846 798 -48 -5.7 1.7 Pass Pass Pass

35 A404 Easton Street East EB Towards Junction with A40 London Road 400 230 -170 -42.5 9.6 Fail Pass Fail

36 A40 London Road WB Towards Junction with Hatters Ln 818 865 47 5.8 1.6 Pass Pass Pass

37 A40 London Road EB Away from Junction with Hatters Ln 884 932 48 5.4 1.6 Pass Pass Pass

38 A40 London Road Westbound between Micklefield Rd and Cock Ln 978 986 8 0.8 0.2 Pass Pass Pass

39 A40 London Road Eastbound between Micklefield Rd and Cock Ln 1235 1196 -39 -3.1 1.1 Pass Pass Pass

40 A40 WB Away from Junction with Station Road 781 734 -47 -6 1.7 Pass Pass Pass

41 A40 EB Towards Junction with Station Road 1126 1217 91 8.1 2.7 Pass Pass Pass

42 A40 WB Towards Junction with Station Road 674 758 84 12.5 3.2 Pass Pass Pass

43 A40 EB Away from Junction with Station Road 969 1109 140 14.5 4.3 Pass Pass Pass

44 A4094 Knaves Beech Way SB Away from Tesco roundabout 760 640 -120 -15.8 4.5 Pass Pass Fail

45 A4094 Knaves Beech Way NB Towards Tesco roundabout 679 565 -114 -16.8 4.6 Pass Pass Fail

46 A40 London Road WB Away from Tesco roundabout 804 680 -124 -15.5 4.6 Pass Pass Fail

47 A40 London Road EB Towards Tesco roundabout 1061 1008 -53 -5 1.6 Pass Pass Pass

48 B474 Elm Road NB Towards Junction with Penn Bottom 304 331 27 8.9 1.5 Pass Pass Pass

49 B474 Elm Road SB Away from Junction with Penn Bottom 569 548 -21 -3.7 0.9 Pass Pass Pass

50 B474 Hazlemere Road NB Away from Junction with Penn Bottom 258 274 16 6.3 1 Pass Pass Pass

51 B474 Hazlemere Road SB Towards Junction with Penn Bottom 677 672 -5 -0.7 0.2 Pass Pass Pass

52 Straight Bit WB Towards Junction with Swains Lane 470 176 -294 -62.6 16.4 Fail Fail Fail

53 Straight Bit EB Away from Junction with Swains Lane 469 222 -247 -52.6 13.3 Fail Fail Fail

54 Treadaway Road SB Away from Junction with Swains Lane 194 299 105 54 6.7 Fail Pass Fail

55 Treadaway Road NB Towards Junction with Swains Lane 108 45 -63 -58.4 7.2 Fail Pass Pass

56 Heath End Road EB Towards Junction with Swains Lane 775 709 -66 -8.5 2.4 Pass Pass Pass

57 Heath End Road WB Away from Junction with Swains Lane 461 495 34 7.5 1.6 Pass Pass Pass

58 Swains Lane SB Towards Junction with Heath End Road 223 317 94 42 5.7 Fail Pass Pass

59 Swains Lane NB Away from Junction with Heath End Road 500 453 -47 -9.4 2.1 Pass Pass Pass

60 Lands End Rd SB Towards Junction with Horns Ln 422 340 -82 -19.4 4.2 Pass Pass Pass

61 Lands End Rd NB Away from Junction with Horns Ln 417 395 -22 -5.3 1.1 Pass Pass Pass

62 Lands End Rd WB Away from Junction with New Road 852 625 -227 -26.6 8.4 Fail Pass Fail

63 Lands End Rd EB Towards Junction with New Road 445 598 153 34.3 6.7 Fail Pass Fail

64 Cressex Road WB Towards Junction with Horns Lane 388 411 23 6 1.2 Pass Pass Pass

65 Cressex Road EB Away from Junction with Horns Lane 650 462 -188 -28.9 8 Fail Pass Fail

66 Desborough Ave SB Away from Junction with Plumer Rd 793 829 36 4.5 1.3 Pass Pass Pass

67 Desborough Ave NB Towards Junction with Plumer Rd 795 834 39 4.9 1.4 Pass Pass Pass

68 Swains Lane SB Away from Junction with Treadaway Road 493 455 -38 -7.7 1.7 Pass Pass Pass

69 Swains Lane NB Towards Junction with Treadaway Road 599 489 -110 -18.3 4.7 Pass Pass Fail

70 Desborough Ave SB Away from Junction with A40 West Wycombe Rd 617 513 -104 -16.9 4.4 Pass Pass Fail

71 Desborough Ave NB Towards Junction with A40 West Wycombe Rd 379 402 23 6.2 1.2 Pass Pass Pass

72 Dashwood Ave WB Towards Junction with Mill End Rd 176 101 -75 -42.4 6.3 Fail Pass Pass

73 Dashwood Ave EB Away from Junction with Mill End Rd 315 336 21 6.6 1.1 Pass Pass Pass

74 Abbey Barn Road WB Towards Junction with Kingsmead Rd 862 748 -114 -13.2 4 Pass Pass Pass

75 Abbey Barn Road EB Away from Junction with Kingsmead Rd 359 333 -26 -7.3 1.4 Pass Pass Pass

76 Cressex Road WB Away from Junction with Marlow Road 394 386 -8 -2 0.4 Pass Pass Pass

77 Cressex Road EB Towards Junction with Marlow Road 518 588 70 13.4 3 Pass Pass Pass

78 Marlow Road SB Towards Junction with Cressex Rd 914 987 73 8 2.4 Pass Pass Pass

79 Marlow Road NB Away from Junction with Cressex Rd 918 1050 132 14.4 4.2 Pass Pass Pass

80 Oxford Street WB Towards A40 Abbey Way Rbt 84 84 0 -0.3 0 Pass Pass Pass

81 Oxford Street EB Away from A40 Abbey Way Rbt 38 34 -4 -10.4 0.7 Pass Pass Pass


82 Cressex Road East WB Towards Junction with Holmers Farm Way 431 456 25 5.8 1.2 Pass Pass Pass

83 Cressex Rd East EB Away from Junction with Holmers Farm Way 390 288 -102 -26.3 5.6 Fail Pass Fail

84 Holmers Farm Way NB Towards Junction with Cressex Road 190 175 -15 -8.1 1.1 Pass Pass Pass

85 Holmers Farm Way SB Away from Junction with Cressex Road 440 500 60 13.6 2.8 Pass Pass Pass

86 Cressex Road West WB Away from Junction with Holmers Farm Way 463 414 -49 -10.6 2.4 Pass Pass Pass

87 Cressex Road West EB Towards Junction with Holmers Farm Way 672 570 -102 -15.1 4.1 Pass Pass Fail

88 Mill End Road South SB Towards Junction With Chapel Lane 558 687 129 23.2 5.2 Fail Pass Fail

89 Mill End Road South NB Away from Junction With Chapel Lane 621 547 -74 -11.9 3.1 Pass Pass Pass

90 Chalfont Way SB Towards Junction with A4010 John Hall Way 210 150 -60 -28.7 4.5 Pass Pass Pass

91 Chalfont Way NB Away from Junction with A4010 John Hall Way 572 494 -78 -13.6 3.4 Pass Pass Pass

92 Cressex Road East WB Towards Junction with A4010 John Hall Way 343 369 26 7.5 1.4 Pass Pass Pass

93 Cressex Road East EB Away from Junction with A4010 John Hall Way 532 452 -80 -15 3.6 Pass Pass Pass

94 Cressex Road West WB Away from Junction with A4010 John Hall Way 352 462 110 31.1 5.4 Fail Pass Fail

95 Cressex Road West EB Towards Junction with A4010 John Hall Way 605 560 -45 -7.4 1.9 Pass Pass Pass

96 Holmers Farm Way SB Away from Junction with A4010 John Hall Way 422 418 -4 -1 0.2 Pass Pass Pass

97 Holmers Farm Way NB Towards Junction with A4010 John Hall Way 320 353 33 10.2 1.8 Pass Pass Pass

98 Morrisons SB Away from Junction with A40 London Road 184 225 41 22.5 2.9 Pass Pass Pass

99 Morrisons NB Towards Junction with A40 London Road 102 110 8 7.5 0.7 Pass Pass Pass

100 Parker Knoll Way WB Away from Junction with A4128 Glenisters Rd 638 484 -154 -24.1 6.5 Fail Pass Fail

101 Parker Knoll Way EB Towards Junction with A4128 Glenisters Rd 474 341 -133 -28 6.6 Fail Pass Fail

102 New Road WB Away from Junction with Hazelmere Rd 287 345 58 20.4 3.3 Pass Pass Pass

103 New Road EB Towards Junction with Hazelmere Rd 167 173 6 3.7 0.5 Pass Pass Pass

104 Station Road SB Away from Junction with A40 479 365 -114 -23.9 5.6 Fail Pass Fail

105 Station Road NB Towards Junction with A40 429 232 -197 -45.8 10.8 Fail Fail Fail

106 Queen Victoria Rd NB Away from Junction with A40 Abbey Way 1008 951 -57 -5.6 1.8 Pass Pass Pass

107 A404 Easton Street West EB Towards Junction with A404 Easton Street East 1116 1080 -36 -3.2 1.1 Pass Pass Pass

108 A404 Marlow Hill South NB Towards Junction with Marlow Rd 1073 1220 147 13.7 4.3 Pass Pass Pass

109 A404 Marlow Hill South SB Away from Junction with Marlow Rd 1097 1140 43 4 1.3 Pass Pass Pass

110 West Wycombe Way East EB Away from Junction with Desborough Ave 885 909 24 2.7 0.8 Pass Pass Pass

111 West Wycombe Way East WB Towards Junction with Desborough Ave 697 760 63 9 2.3 Pass Pass Pass

112 A404 Marlow Hill Towards Junction 1643 1501 -142 -8.6 3.6 Pass Pass Pass

113 A404 Marlow Hill Away from Junction 1401 1291 -110 -7.8 3 Pass Pass Pass

114 Handycross M40 Westbound 1773 1984 211 11.9 4.9 Pass Pass Pass

115 Handycross M40 Eastbound 2778 2974 196 7 3.6 Pass Pass Pass

116 A404 Marlow Hill North Towards Junction 2050 1824 -226 -11 5.1 Fail Pass Pass

117 A404 Marlow Hill North Away from Junction 1862 1588 -274 -14.7 6.6 Fail Pass Pass

118 Turnpike Road EB Away from Junction with New Road 530 359 -171 -32.3 8.1 Fail Pass Fail

119 Turnpike Road WB Towards Junction with New Road 136 113 -23 -16.9 2.1 Pass Pass Pass

120 Mill End Road North NB Away from Junction with Dashwood Ave 377 222 -155 -41 8.9 Fail Pass Fail

121 Mill End Road North SB Towards Junction with Dashwood Ave 451 603 152 33.8 6.6 Fail Pass Fail

Summary Validation Statistics

Criteria GEH <5

Criteria GEH <10

Criteria Flow

Pass 95 117 88

Fail 26 4 33

Total 121 121 121

% 79% 97% 73%


PM Validation Table

Link No.

Location / Movement Observed

(no. of vehicles)

Modelled (no. of

vehicles)


% Difference

GEH Criteria GEH <5

Criteria GEH <10

Criteria Flow

1 A4010 New Road NB Towards Junction with Land End Rd 738 835 97 13.2 3.5 Pass Pass Pass

2 A4010 New Road SB Away from with Lands End Rd 675 782 107 15.8 4 Pass Pass Fail

3 A40 West Wycombe Rd WB Towards Junction with Plomer Hill 1151 1106 -45 -3.9 1.3 Pass Pass Pass

4 A40 West Wycombe Rd EB Away from Junction with Plomer Hill 596 632 36 6 1.5 Pass Pass Pass

5 A40 West Wycombe Rd WB Away from Junction with Plomer Hill 981 889 -92 -9.4 3 Pass Pass Pass

6 A40 West Wycombe Rd EB Towards Junction with Plomer Hill 656 561 -95 -14.5 3.9 Pass Pass Pass

7 A40 West Wycombe Way West WB Away from Junction with Desborough Ave 745 810 65 8.8 2.3 Pass Pass Pass

8 A40 West Wycombe Way West EB Towards Junction with Desborough Ave 730 637 -93 -12.7 3.6 Pass Pass Pass

9 A404 Amersham Road SB Towards Junction with Totteridge Ln 898 938 40 4.5 1.3 Pass Pass Pass

10 A404 Amersham Road NB Away from Junction with Totteridge Ln 954 1042 88 9.2 2.8 Pass Pass Pass

11 A404 Crendon Street SB Toward Junction with Totteridge Rd 485 401 -84 -17.4 4 Pass Pass Pass

12 A404 Crendon Street NB Away from Junction with Totteridge Rd 640 699 59 9.3 2.3 Pass Pass Pass

13 A404 Amersham Road SB Towards Junction with Green St 950 851 -99 -10.4 3.3 Pass Pass Pass

14 A404 Amersham Road NB Away from Junction with Green St 975 945 -30 -3 1 Pass Pass Pass

15 A404 Amersham Road SB Towards Junction with Hamilton Rd 644 643 -1 -0.1 0 Pass Pass Pass

16 A404 Amersham Road NB Away from Junction with Hamilton Rd 867 997 130 15 4.3 Pass Pass Fail

17 A40 London Road WB Towards Junction with Gomm Rd 819 943 124 15.2 4.2 Pass Pass Fail

18 A40 London Road EB Away from Junction with Gomm Rd 885 816 -69 -7.8 2.4 Pass Pass Pass

19 A404 Easton Street SB Towards Junction with A40 Abbey Way 1013 961 -52 -5.1 1.7 Pass Pass Pass

20 A4010 New Rd SB Towards Junction with Lane End Rd 968 1058 90 9.3 2.8 Pass Pass Pass

21 A4010 New Rd NB Away from Junction with Lane End Rd 1111 1162 51 4.6 1.5 Pass Pass Pass

22 A4010 John Hall Way NB Towards Junction with Cressex Rd 854 741 -113 -13.2 4 Pass Pass Pass

23 A4010 John Hall Way SB Away from Junction with Cressex Rd 691 732 41 5.9 1.5 Pass Pass Pass

24 A4010 New Rd NB Towards Junction with Turnpike Rd 1035 939 -96 -9.3 3.1 Pass Pass Pass

25 A4010 New Rd SB Away from Junction with Turnpike Rd 885 813 -72 -8.2 2.5 Pass Pass Pass

26 A40 Abbey Way West Away from Abbey Way Gyratory 1343 1263 -80 -5.9 2.2 Pass Pass Pass

27 A40 Abbey Way West towards Abbey Way Gyratory 1081 898 -183 -17 5.8 Fail Pass Fail

28 A40 Abbey Way NB Away from Junction with Lilys Walk 1249 1050 -199 -16 5.9 Fail Pass Fail

29 A40 Abbey Way WB Towards Roundabout 2148 2040 -108 -5 2.4 Pass Pass Pass

30 A40 Abbey Way EB Away from Roundabout 748 703 -45 -6 1.7 Pass Pass Pass

31 A404 Amersham Rd SB Towards Junction with Amison Ave 671 648 -23 -3.4 0.9 Pass Pass Pass

32 A404 Amersham Rd NB Away from Junction with Amison Ave 843 957 114 13.5 3.8 Pass Pass Pass

33 A404 Amersham Road South Westbound between Totteridge Ln and Kingshill Rd 972 1003 31 3.2 1 Pass Pass Pass

34 A404 Amersham Road North East bound between Totteridge Ln and Kingshill Rd 1057 1060 3 0.3 0.1 Pass Pass Pass

35 A404 Easton Street East EB Towards Junction with A40 London Road 207 300 93 45.1 5.9 Fail Pass Pass

36 A40 London Road WB Towards Junction with Hatters Ln 1218 1166 -52 -4.3 1.5 Pass Pass Pass

37 A40 London Road EB Away from Junction with Hatters Ln 829 841 12 1.5 0.4 Pass Pass Pass

38 A40 London Road Westbound between Micklefield Rd and Cock Ln 1532 1394 -138 -9 3.6 Pass Pass Pass

39 A40 London Road Eastbound between Micklefield Rd and Cock Ln 1005 1100 95 9.5 2.9 Pass Pass Pass

40 A40 WB Away from Junction with Station Road 1092 1116 24 2.2 0.7 Pass Pass Pass

41 A40 EB Towards Junction with Station Road 989 789 -200 -20.3 6.7 Fail Pass Fail

42 A40 WB Towards Junction with Station Road 803 998 195 24.3 6.5 Fail Pass Fail

43 A40 EB Away from Junction with Station Road 922 803 -119 -12.9 4.1 Pass Pass Pass

44 A4094 Knaves Beech Way SB Away from Tesco roundabout 766 717 -49 -6.3 1.8 Pass Pass Pass

45 A4094 Knaves Beech Way NB Towards Tesco roundabout 535 471 -64 -12 2.9 Pass Pass Pass

46 A40 London Road WB Away from Tesco roundabout 1020 977 -43 -4.2 1.4 Pass Pass Pass

47 A40 London Road EB Towards Tesco roundabout 815 695 -120 -14.7 4.4 Pass Pass Pass

48 B474 Elm Road NB Towards Junction with Penn Bottom 597 710 113 18.9 4.4 Pass Pass Fail

49 B474 Elm Road SB Away from Junction with Penn Bottom 275 342 67 24.4 3.8 Pass Pass Pass

50 B474 Hazlemere Road NB Away from Junction with Penn Bottom 605 700 95 15.7 3.7 Pass Pass Pass

51 B474 Hazlemere Road SB Towards Junction with Penn Bottom 357 471 114 31.8 5.6 Fail Pass Fail

52 Straight Bit WB Towards Junction with Swains Lane 325 197 -128 -39.3 7.9 Fail Pass Fail

53 Straight Bit EB Away from Junction with Swains Lane 291 146 -145 -49.7 9.8 Fail Pass Fail

54 Treadaway Road SB Away from Junction with Swains Lane 162 201 39 23.9 2.9 Pass Pass Pass

55 Treadaway Road NB Towards Junction with Swains Lane 133 151 18 13.2 1.5 Pass Pass Pass

56 Heath End Road EB Towards Junction with Swains Lane 570 579 9 1.6 0.4 Pass Pass Pass

57 Heath End Road WB Away from Junction with Swains Lane 682 654 -28 -4.1 1.1 Pass Pass Pass

58 Swains Lane SB Towards Junction with Heath End Road 531 458 -73 -13.7 3.3 Pass Pass Pass

59 Swains Lane NB Away from Junction with Heath End Road 432 433 1 0.3 0.1 Pass Pass Pass

60 Lands End Rd SB Towards Junction with Horns Ln 345 366 21 6.1 1.1 Pass Pass Pass

61 Lands End Rd NB Away from Junction with Horns Ln 262 338 76 29.2 4.4 Pass Pass Pass

62 Lands End Rd WB Away from Junction with New Road 388 414 26 6.8 1.3 Pass Pass Pass

63 Lands End Rd EB Towards Junction with New Road 468 465 -3 -0.6 0.1 Pass Pass Pass

64 Cressex Road WB Towards Junction with Horns Lane 593 491 -102 -17.2 4.4 Pass Pass Fail

65 Cressex Road EB Away from Junction with Horns Lane 485 479 -6 -1.2 0.3 Pass Pass Pass

66 Desborough Ave SB Away from Junction with Plumer Rd 644 721 77 12 3 Pass Pass Pass

67 Desborough Ave NB Towards Junction with Plumer Rd 879 1019 140 15.9 4.5 Pass Pass Fail

68 Swains Lane SB Away from Junction with Treadaway Road 514 570 56 11 2.4 Pass Pass Pass

69 Swains Lane NB Towards Junction with Treadaway Road 523 517 -6 -1.1 0.3 Pass Pass Pass

70 Desborough Ave SB Away from Junction with A40 West Wycombe Rd 399 439 40 10 1.9 Pass Pass Pass

71 Desborough Ave NB Towards Junction with A40 West Wycombe Rd 500 588 88 17.6 3.8 Pass Pass Pass

72 Dashwood Ave WB Towards Junction with Mill End Rd 217 194 -23 -10.4 1.6 Pass Pass Pass

73 Dashwood Ave EB Away from Junction with Mill End Rd 256 306 50 19.7 3 Pass Pass Pass

74 Abbey Barn Road WB Towards Junction with Kingsmead Rd 391 415 24 6.1 1.2 Pass Pass Pass

75 Abbey Barn Road EB Away from Junction with Kingsmead Rd 802 675 -127 -15.8 4.7 Pass Pass Fail

76 Cressex Road WB Away from Junction with Marlow Road 504 556 52 10.4 2.3 Pass Pass Pass

77 Cressex Road EB Towards Junction with Marlow Road 473 611 138 29.1 5.9 Fail Pass Fail

78 Marlow Road SB Towards Junction with Cressex Rd 997 971 -26 -2.7 0.8 Pass Pass Pass

79 Marlow Road NB Away from Junction with Cressex Rd 939 1083 144 15.4 4.5 Pass Pass Fail

80 Oxford Street WB Towards A40 Abbey Way Rbt 170 126 -44 -26.2 3.7 Pass Pass Pass

81 Oxford Street EB Away from A40 Abbey Way Rbt 35 32 -3 -8 0.5 Pass Pass Pass

82 Cressex Road East WB Towards Junction with Holmers Farm Way 463 354 -109 -23.5 5.4 Fail Pass Fail

83 Cressex Rd East EB Away from Junction with Holmers Farm Way 479 485 6 1.2 0.3 Pass Pass Pass

84 Holmers Farm Way NB Towards Junction with Cressex Road 448 432 -16 -3.6 0.8 Pass Pass Pass

85 Holmers Farm Way SB Away from Junction with Cressex Road 295 371 76 25.8 4.2 Pass Pass Pass


86 Cressex Road West WB Away from Junction with Holmers Farm Way 686 508 -178 -26 7.3 Fail Pass Fail

87 Cressex Road West EB Towards Junction with Holmers Farm Way 549 577 28 5.1 1.2 Pass Pass Pass

88 Mill End Road South SB Towards Junction With Chapel Lane 540 577 37 6.9 1.6 Pass Pass Pass

89 Mill End Road South NB Away from Junction With Chapel Lane 656 700 44 6.7 1.7 Pass Pass Pass

90 Chalfont Way SB Towards Junction with A4010 John Hall Way 644 685 41 6.3 1.6 Pass Pass Pass

91 Chalfont Way NB Away from Junction with A4010 John Hall Way 129 127 -2 -1.6 0.2 Pass Pass Pass

92 Cressex Road East WB Towards Junction with A4010 John Hall Way 495 579 84 17.1 3.6 Pass Pass Pass

93 Cressex Road East EB Away from Junction with A4010 John Hall Way 450 556 106 23.5 4.7 Pass Pass Fail

94 Cressex Road West WB Away from Junction with A4010 John Hall Way 459 402 -57 -12.3 2.7 Pass Pass Pass

95 Cressex Road West EB Towards Junction with A4010 John Hall Way 401 495 94 23.5 4.5 Pass Pass Pass

96 Holmers Farm Way SB Away from Junction with A4010 John Hall Way 638 616 -22 -3.4 0.9 Pass Pass Pass

97 Holmers Farm Way NB Towards Junction with A4010 John Hall Way 569 551 -18 -3.1 0.7 Pass Pass Pass

98 Morrisons SB Away from Junction with A40 London Road 264 194 -70 -26.7 4.7 Pass Pass Pass

99 Morrisons NB Towards Junction with A40 London Road 342 330 -12 -3.6 0.7 Pass Pass Pass

100 Parker Knoll Way WB Away from Junction with A4128 Glenisters Rd 500 442 -58 -11.6 2.7 Pass Pass Pass

101 Parker Knoll Way EB Towards Junction with A4128 Glenisters Rd 794 664 -130 -16.4 4.8 Pass Pass Fail

102 New Road WB Away from Junction with Hazelmere Rd 188 281 93 49.5 6.1 Fail Pass Pass

103 New Road EB Towards Junction with Hazelmere Rd 147 110 -37 -25.1 3.2 Pass Pass Pass

104 Station Road SB Away from Junction with A40 292 220 -72 -24.8 4.5 Pass Pass Pass

105 Station Road NB Towards Junction with A40 514 352 -162 -31.4 7.8 Fail Pass Fail

106 Queen Victoria Rd NB Away from Junction with A40 Abbey Way 822 996 174 21.2 5.8 Fail Pass Fail

107 A404 Easton Street West EB Towards Junction with A404 Easton Street East 1220 1262 42 3.4 1.2 Pass Pass Pass

108 A404 Marlow Hill South NB Towards Junction with Marlow Rd 1100 1206 106 9.7 3.1 Pass Pass Pass

109 A404 Marlow Hill South SB Away from Junction with Marlow Rd 1330 1561 231 17.4 6.1 Fail Pass Fail

110 West Wycombe Way East EB Away from Junction with Desborough Ave 738 756 18 2.4 0.6 Pass Pass Pass

111 West Wycombe Way East WB Towards Junction with Desborough Ave 1009 1186 177 17.6 5.4 Fail Pass Fail

112 A404 Marlow Hill Towards Junction 1580 1654 74 4.7 1.8 Pass Pass Pass

113 A404 Marlow Hill Away from Junction 1187 1331 144 12.1 4 Pass Pass Pass

114 Handycross M40 Westbound 2529 2732 203 8 4 Pass Pass Pass

115 Handycross M40 Eastbound 2315 2439 124 5.4 2.5 Pass Pass Pass

116 A404 Marlow Hill North Towards Junction 1962 1986 24 1.2 0.5 Pass Pass Pass

117 A404 Marlow Hill North Away from Junction 1784 1907 123 6.9 2.9 Pass Pass Pass

118 Turnpike Road EB Away from Junction with New Road 102 58 -44 -43.4 4.9 Pass Pass Pass

119 Turnpike Road WB Towards Junction with New Road 289 222 -67 -23.2 4.2 Pass Pass Pass

120 Mill End Road North NB Away from Junction with Dashwood Ave 485 411 -74 -15.3 3.5 Pass Pass Pass

121 Mill End Road North SB Towards Junction with Dashwood Ave 403 410 7 1.8 0.4 Pass Pass Pass

Summary Validation Statistics

Criteria GEH <5

Criteria GEH <10

Criteria Flow

Pass 105 121 97

Fail 16 0 24

Total 121 121 121

% 87% 100% 80%


Appendix B Traffic Volume Data Availability

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High Wycombe Data Availability 2013


Appendix C M40 Junction 4 (Handy Cross) TRADS Data


TRADS data availability

January 2013

Working

Not working

Entry

Exit

The figure indicates all the TRADS locations. To supplement the sites not working along the approach from Wycombe Road (south) an ATC counter will be placed at this location during March 2013.

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