GBATS4M Model Update
METROWEST Highway Model Local Model Validation Report
West of England AutPhreoprairteidefosr
08 October 2015
1 The Square Temple Quay
Bristol
BS1 6DG
Document History
GBATS4M Model Update METROWEST Highway Model LMVR West of England Authorities
This document has been issued and amended as follows:
- Version
- Date
- Description
- Created by
- Verified by
- Approved by
- 1.0
- 17.10.2014
- Initial Draft Report
- Pete
Knightbridge
1.1
1.2
- 14.4.2015
- Draft Report
Final Report
Pete Knightbridge
Katherine Williams
Chris Bushell
- Chris Bushell
- 08.10.2015
- Pete
Knightbridge
Katherine Williams
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Contents
- Section
- Page
1.1 1.2
Background ................................................................................................................................6 Report Structure ........................................................................................................................7
2.1 2.2 2.3
MetroWest.................................................................................................................................8 Potential Further Uses ...............................................................................................................8 Model Design Considerations....................................................................................................8
Model Standards, Criteria and Acceptability Guidelines ..............................................................10
3.1 3.2 3.3 3.4
Overview..................................................................................................................................10 Validation Criteria and Acceptability Guidelines .....................................................................10 Convergence Criteria and Standards .......................................................................................11 Trip Matrix Changes.................................................................................................................11
Key Features of the Model .........................................................................................................13
4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9
Source Model...........................................................................................................................13 Modelling software..................................................................................................................13 Base Year..................................................................................................................................13 Model Network Area ...............................................................................................................13 Time Periods ............................................................................................................................15 Pre Peak Queuing.....................................................................................................................15 Zoning System..........................................................................................................................15 Signal Timings ..........................................................................................................................17 User Classes .............................................................................................................................17
4.10 Assignment Methodology........................................................................................................17 4.11 Representation of Car Parks ....................................................................................................18 4.12 Generalised Cost and Parameter Values .................................................................................18 4.12.1 Values of Time .........................................................................................................................18 4.12.2 Vehicle Operating Costs...........................................................................................................19
Survey Data ...............................................................................................................................20
5.1 5.2
Overview..................................................................................................................................20 Roadside Interview Sites..........................................................................................................21 Sample Size and Logic Checks..................................................................................................21 Traffic Counts on Cordons and Screenlines.............................................................................22 Data Processing........................................................................................................................27 Journey Time Surveys ..............................................................................................................27 Accuracy of Journey Time Surveys...........................................................................................28
5.3 5.4 5.5 5.6
Network Development...............................................................................................................30
6.1 6.2 6.3 6.4
Source Networks......................................................................................................................30 Link Coding...............................................................................................................................30 Junction Coding........................................................................................................................31 Centroid Connectors................................................................................................................31
GBATS4M HIGHWAY MODEL LMVR
Trip Matrix Development...........................................................................................................32
7.1 7.2 7.3 7.4 7.5
Matrix Development process .................................................................................................. 32 GBATS3 Matrix Merge............................................................................................................. 32 RSI Data ................................................................................................................................... 33 Merging RSI Data..................................................................................................................... 33 Calibration of the Initial Trip Matrices .................................................................................... 34
Network Calibration and Validation............................................................................................35
8.1 8.2 8.3
Network Calibration ................................................................................................................ 35 Route Choice Calibration......................................................................................................... 35 Route Choice Validation.......................................................................................................... 36
Trip Matrix Calibration and Validation........................................................................................37
9.1 9.2 9.3 9.4 9.5
Prior Trip Matrix ...................................................................................................................... 37 Application of Matrix Estimation............................................................................................. 37 Changes due to Matrix Estimation.......................................................................................... 37 Park and Ride Matrices............................................................................................................ 39 Further Trip Matrix Segmentation .......................................................................................... 39
Assignment Calibration and Validation .......................................................................................41
10.1 Overview.................................................................................................................................. 41 10.2 Cruise Times ............................................................................................................................ 41 10.3 Traffic Flows ............................................................................................................................ 43 10.4 Journey Times.......................................................................................................................... 49 10.5 Model Convergence ................................................................................................................ 50 10.6 Stress Test ............................................................................................................................... 50
Conclusion.................................................................................................................................51
11.1 Overview.................................................................................................................................. 51
Appendix A: Other Traffic Count Sites.....................................................................................................52 Appendix B: Network Coding Standards..................................................................................................54 Appendix C: Matrix Estimation Checks....................................................................................................56 Appendix D: Route Choice Calibration ....................................................................................................62 Appendix E: Traffic Link Flow Validation .................................................................................................77 Appendix F: Distance-Travel Time Graphs............................................................................................. 104 Appendix G: Model Convergence Graphs.............................................................................................. 105
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Figures
Figure 1.1 - GBATS3 Localised Core Areas ............................................................................................................................6 Figure 1.2 - GBATS4M Modelling Suite.................................................................................................................................7 Figure 2.1 - Metro Corridors .................................................................................................................................................8 Figure 4.1 - GBATS4M Highway Model Central Modelled Area..........................................................................................14 Figure 4.2 - GBATS4M Highway Model Fully Modelled Are a . .............................................................................................14 Figure 4.3 - GBATS4M Central Model Area Zones ..............................................................................................................16 Figure 4.4 - GBATS4M Wider Model Area Zones ................................................................................................................16 Figure 5.1 - City Centre RSI Locations .................................................................................................................................21 Figure 5.2- Calibration Traffic Count Sites ..........................................................................................................................26 Figure 5.3- Validation Traffic Count Sites ...........................................................................................................................26 Figure 5.4 - GBATS4M Highway Model Journey Time Survey Routes .................................................................................28 Figure 6.1 - GBATS4M Free Flow Spee d . .............................................................................................................................31 Figure 9.1 - GBATS4M Sector Pla n . .....................................................................................................................................38 Figure 10.1 - AM Peak Traffic Flow Validation and Calibration Screenlines .......................................................................44 Figure 10.2 - Inter Peak Traffic Flow Validation and Calibration Screenlines .....................................................................46 Figure 10.3 - PM Peak Traffic Flow Validation and Calibration Screenlines .......................................................................48
Tables
Table 3.1 - DMRB Acceptability Guidelines.........................................................................................................................10 Table 3.2- TAG M3.1 Convergence Criteria.........................................................................................................................11 Table 3.3 - TAG M3.1 Significance of Matrix Estimation changes ......................................................................................12 Table 4.1 - Vehicle to PCU Factors ......................................................................................................................................17 Table 4.2 - Generalised User Class - Value of Time and Distance .......................................................................................19 Table 5.1 - Calibration Traffic Count Data ..........................................................................................................................23 Table 5.2 - Validation Traffic Count Data ...........................................................................................................................25 Table 5.3 – Monthly Traffic Flow Factors ...........................................................................................................................27 Table 5.4 - Annual Traffic Flow Factors ..............................................................................................................................27 Table 5.5 - Accuracy of Journey Time Data.........................................................................................................................29 Table 7.1 – CSM RSI Locations Used ...................................................................................................................................32 Table 7.2 - Initial Trip Matrix Comparison ..........................................................................................................................34 Table 9.1 - Matrix Estimation (Prior vs Post ME2 matrix) Regression Analysis Summary ..................................................38 Table 9.2 - Matrix Estimation (Prior vs Post ME2 matrix) Total Mean Trip Length ............................................................38 Table 9.3 - Matrix Estimation (Prior vs Post ME2 matrix) Sector Matrix Changes .............................................................39 Table 9.4 - RSI Light Vehicle User Class Splits .....................................................................................................................39 Table 9.5 - RSI Light Vehicle User Class Splits .....................................................................................................................40 Table 10.1 – Inter-Peak Model Cruise Time Check..............................................................................................................42 Table 10.2 – AM Peak Link Flow Validation Summary........................................................................................................43 Table 10.3 – Inter Peak Link Flow Validation Summary......................................................................................................45 Table 10.4 – PM Peak Link Flow Validation Summar y . .......................................................................................................47 Table 10.5 - GBATS4M Net Journey Time (mins) Validation ...............................................................................................49 Table 10.6 - GBATS4M Convergence Summary ..................................................................................................................50
Figures contain Ordnance Survey Data - Crown Copyright All Rights Reserved. Bristol City Council 100023406
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SECTION 1
Introduction
1.1 Background
This report has been prepared by CH2M Hill as part of their commission to update the Greater Bristol Area Transport Study (GBATS) modelling suite for Bristol City Council (BCC), on behalf of the West of England authorities.
The updated GBATS model has been specified to be suitable for assessing the MetroWest major scheme Phases 1 and 2. The Bristol Area Traffic Study (BATS) model was originally built and validated to a base year of 2001. Since then it has been updated to BATS2 as a part of the Greater Bristol Bus Network study in 2004 and further updated to the GBATS3 strategic model with a base year of 2006. The GBATS3 model was used as the starting point for four localised studies. In each case the model was updated, recalibrated and revalidated with the local study area core as its focus. Figure 1.1 shows the core areas of the localised models. The four studies are below:
Ashton Vale to Temple Meads Rapid Transit (AVTM, 2006 Base year, 580 active zones); Northern Fringe to Hengrove Package (NFHP, 2009, 584); South Bristol Link (SBL, 2009 & 2012, 616); and South Gloucestershire Core Strategy (SGCS, 2011, 591).
Figure 1.1 - GBATS3 Localised Core Areas
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The updated model is called the GBATS4 Metro Model (GBATS4M). The GBATS4M model consists of:
A Highway Assignment Model representing vehicle based movements across the Greater Bristol area for a 2013 autumn weekday morning peak hour (08:00-09:00), an average inter-peak hour (10:00-16:00) and an evening peak hour (17:00-18:00);
A Public Transport (PT) Assignment Model representing bus and rail based movements across the same area and time periods; and A five-stage multi-modal incremental Variable Demand Model (VDM) that forecasts changes in trip frequency and choice of main mode, time period of travel, destination, and sub-mode choice, in response to changes in generalised costs across the 12-hour period (07:00 – 19:00).
The GBATS4M highway model is closely integrated with the GBATS4M PT model. The two models use different software packages (SATURN and EMME, respectively) but are identical in terms of road network structure, and zone system. The bus routes and frequencies in the PT model are used in the highway model.
The GBATS4M highway model is fully integrated within the GBATS4M VDM. The GBATS4M highway model provides highway transport costs to the GBATS4M VDM which, in turn, provides trip matrices for the GBATS4M highway model. The relationship between the elements of the modelling system is shown in Figure 1.2.
Figure 1.2 - GBATS4M Modelling Suite
1.2 Report Structure
This model development report consists of the following sections, after the Introduction:
Section 2 – Model Usage and Design Considerations; Section 3 – Model Standards, Criteria and Acceptability Guidelines; Section 4 – Key Features of the model; Section 5 – Survey Data; Section 6 – Network Development; Section 7 – Trip Matrix Development; Section 8 – Network Calibration and Validation; Section 9 – Trip Matrix Calibration and Validation; Section 10 – Assignment Calibration and Validation and Section 11 – Conclusion
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GBATS4M HIGHWAY MODEL LMVR
SECTION 2
Model Usage and Design Considerations
2.1 MetroWest
The GBATS4M modelling suite provides a tool with which to test the ability of future transport proposals to support forecast travel demand. At a general level this includes:
