rims update - best practice: traffic count estimation
DESCRIPTION
RIMS Forum 22 March 2012 by Matthew Rodwell Hastings District CouncilTRANSCRIPT
![Page 1: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/1.jpg)
RIMS Best Practice:Traffic Count Estimation
2012 Road Asset & InformationManagement Forum
![Page 2: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/2.jpg)
Ministry of TransportStuart Badger
Acknowledgements
MWH New ZealandFergus Tate
![Page 3: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/3.jpg)
Traffic Count Estimation:
research result is a proposed traffic monitoring framework that significantly
improves the overall accuracy and efficiency (and therefore value for
money) of typical traffic data collection regimes
![Page 4: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/4.jpg)
Proposed Traffic Monitoring Framework
• creation of a traffic link model• core annual monitoring sample • rotational sample (80/20)• Linking estimates
![Page 5: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/5.jpg)
•Why is it important•RIMS Objective•Background
•Sampling Framework• Improving Traffic Estimates•Other Considerations
Contents
![Page 6: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/6.jpg)
•AADT shows network traffic levels•Basis for local & national traffic monitoring•Reasons for RCAs to have accurate estimates
1. Better Decision Making2. Used in LoS & Benchmarking3. Funding Decisions
Why is it Important?
![Page 7: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/7.jpg)
Uses of Traffic Count DataLong term planning
Network Renewal & Development
Customer Service Operational
Network traffic levels
Project planning Responding to enquiries
TM requirements
TSA & Predictive modelling
Pavement &capacity design
Development control & planning
Regulatory requirements
Safety studies & crash analysis
Loading for bridge design
Network monitoring
Traffic modelling & simulation
Project economics (BCR)
MIS
LOS & Policy Development
HCV management
![Page 8: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/8.jpg)
1. RIMS intention: an applied guide2. Improve traffic counting outcomes and
value for money3. Presentation will cover some of the
technical research details & elements of the applied guide
RIMS Objective
![Page 9: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/9.jpg)
Ministry of Transport Research: “Updating National Traffic Data: Stage 1 and 2 Final Report” (HyderConsulting and MWH New Zealand Limited, 2005)
Prompted due to realisation that data held across RCAs was very unreliable
Background
![Page 10: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/10.jpg)
0% 50% 100%
50%
30%
0%
10%
40%
20%
25% 75%
Net
wor
k %
with
Cou
nts
< 5
yrs
old
% of RCAs
Data Confidence
![Page 11: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/11.jpg)
![Page 12: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/12.jpg)
1. Improving the efficiency of traffic counting programmes• Increasing the coverage• Improve relevancy of data collected
2. Improving Traffic Estimates• Improving the estimates on uncounted road sections• Improving the updating of estimates
3. Facilitate RCA implementation
Research Goals
![Page 13: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/13.jpg)
1. Pilot the proposed framework in three RCAs: • Upper Hutt [urban], Southland [rural] & Hastings [mixed]
2. Nation-wide survey of traffic monitoring practices in RCAs.
Latest Work
![Page 14: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/14.jpg)
• creating a traffic link network from the spatially referenced RAMM database
• fitting the proposed stratified sampling method to this network
Approach
![Page 15: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/15.jpg)
1. Create Spatial Network2. Aggregate sections that carry the same traffic 3. Relate sections subject to the same growth
effects (parent/child)• Maximises network coverage• Optimises size of sampling framework
Traffic Link Network / Model
![Page 16: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/16.jpg)
RAMM Cway id: 1949
RAMM Cway_id: 1952
Node 2000 Node 2001 Node 2003 Node 2004 Node 2007
RAMM Cway_id: 1953
RAMM Cway id: 1950
RAMM Cway id: 1951
Node 2005Node 2006
Legend: RAMM C_way section node point
![Page 17: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/17.jpg)
RAMM Cway id: 1949
RAMM Cway_id: 1952
T.Link_id: 949 T.Link_id: 1950 T.Link id: 1951
Node 2000 Node 2001 Node 2003 Node 2004 Node 2007
RAMM Cway_id: 1953
RAMM Cway id: 1950
RAMM Cway id: 1951
Node 2005Node 2006
Legend:Node point derived from Spatial model RAMM C_way section node point Combined spatial and RAMM C_way section node point
![Page 18: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/18.jpg)
0%
80%
60%
100%
40%
20%
Size
of T
raff
ic L
ink
Mod
el
RCA
![Page 19: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/19.jpg)
Two distinct needs for traffic count data. • monitoring of travel activity, at a local, regional, or national level• determining traffic volumes and travel on individual roads
1. core sample - for monitoring travel activity2. rotational sample - to cover the road network.
Sampling Framework
![Page 20: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/20.jpg)
National Traffic Database Project - Dr M K Mara developed a sampling framework to estimate the total vehicle travel within an RCA, to a given level of precision.
Core Sample
![Page 21: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/21.jpg)
0% 60% 100%
B5
15,000
0
5,000
20,000
10,000
40% 80%
ADT
Proportion of Links
90%
B4 B3 B2 B1
![Page 22: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/22.jpg)
Nominal Precision
Hastings District Council
+/-10% +/-5%AA
DT
Qua
ntile
<40% 2 7
40-60% 3 8
60-80% 8 31
80-90% 6 23
90-100% 27 107
Total 46 175
Core Sample Size Requirements
![Page 23: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/23.jpg)
•The aim of the rotational sample is to ensure that over time traffic data is collected on, or is applicable to, as much of the network as possible.
•Focuses on capturing majority of network VKT
Rotational Sample
![Page 24: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/24.jpg)
RCA
Proportion of Total Vehicle Kilometres of Travel Contained in the Model
25% Model 50% Model
Hastings District Council 87% 97%
Upper Hutt City Council 86% 97%
Southland District Council 84% 95%
Rotational Sample Coverage
![Page 25: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/25.jpg)
Sample Size vs. Network Coverage
![Page 26: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/26.jpg)
Sample Size vs. Network Coverage
![Page 27: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/27.jpg)
Counting approximately 17% of the traffic links p.a. would:
1. satisfy the core sampling requirements2. Cover 80% of the total vkt (two year rotational cycle),3. provide sufficient additional capacity to retain the
investment in the historic monitoring programme
Pilot Area Results
![Page 28: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/28.jpg)
•Sections of road are linked•Approximate relationships (e.g. growth trends) can be assumed
•Linking sections can improve confidence on unmonitored sections
Traffic Estimates
![Page 29: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/29.jpg)
Traffic Estimates
Z
Z0.95Z0.65Z
Y=0.45Z
0.2Z
Y
0.5Y
0.5Y
A B
C
![Page 30: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/30.jpg)
1. Data use / type of data you want2. HCV Traffic3. Growth Node4. Seasonality5. Traffic modelling
Other Considerations
![Page 31: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/31.jpg)
Traffic ModellingCapture movement patterns
• Cordons• Screen-lines
![Page 32: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/32.jpg)
• Traffic count data is important
• Monitoring framework improves the overall accuracy and efficiency
• 3 Key foundations to strategy:• creation of a traffic link model• core annual monitoring sample of between 3% and 7% links• 2 year rotational sample (top 20% of VKT links)
• Other considerations to make• HCVs• Seasonality• Network Change• Cordons & screen-lines
Summary
![Page 33: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/33.jpg)
Process Review
1 2 3 4
9 10 11
8 7 6 5
![Page 34: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/34.jpg)
2 3 4
9 10 11
8 7 6 5
SpatialiseRAMM Data
![Page 35: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/35.jpg)
3 4
9 10 11
8 7 6 5
1Update ADT estimates to same base
![Page 36: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/36.jpg)
1 2 4
9 10 11
8 7 6 5
Homogenise network to form traffic
links
![Page 37: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/37.jpg)
1 2 3
9 10 11
8 7 6 5
Relate Links (e.g. by ADT % or Growth
etc.)
![Page 38: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/38.jpg)
1 2 3 4
9 10 11
8 7 6 Stratify Network
![Page 39: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/39.jpg)
1 2 3 4
9 10 11
8 7 5Select
random sample for
CORE SITES
![Page 40: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/40.jpg)
1 2 3 4
9 10 11
8 6 5Select 20% with highest
VKT for ROTATIONAL
SITES
![Page 41: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/41.jpg)
1 2 3 4
9 10 11
7 6 5Substitute
sites:Core sample Historic sites Other goals
![Page 42: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/42.jpg)
1 2 3 4
10 11
8 7 6 5
Set Frequency for Counts
![Page 43: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/43.jpg)
1 2 3 4
9 11
8 7 6 5
Produce Programme
![Page 44: RIMS Update - Best Practice: Traffic Count Estimation](https://reader034.vdocuments.mx/reader034/viewer/2022050807/545b3191af79592b448b614e/html5/thumbnails/44.jpg)
1 2 3 4
9 10
8 7 56
Aim to count 15-20% of your links annually