A428 Black Cat to Caxton Gibbet improvements TR010044 Volume 7 7.10 Combined Modelling and Appraisal Report Planning Act 2008 Regulation 5(2)(q) Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009 26 February 2021 A428 Black Cat to Caxton Gibbet improvements Combined Modelling and Appraisal Report Infrastructure Planning Planning Act 2008 The Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009 A428 Black Cat to Caxton Gibbet improvements Development Consent Order 202[ ] Combined Modelling and Appraisal Report Regulation Reference: Regulation 5(2)(q) Planning Inspectorate Scheme TR010044 Reference Application Document Reference TR010044/APP/) 7.10 Author A428 Black Cat to Caxton Gibbet Project Team, Highways England Version Date Status of Version Rev 1 26 February 2021 DCO Application Planning Inspectorate Scheme Ref: TR010044 Application Document Ref: TR010044/APP/7.10 A428 Black Cat to Caxton Gibbet improvements Combined Modelling and Appraisal Report Table of contents Chapter Pages Executive Summary 1 1 Introduction 5 1.1 Purpose 5 1.2 Background 6 1.3 Scheme description 8 1.4 Report structure 10 2 Local transport summary 11 2.1 Overview 11 2.2 Description of the local transport system 11 2.3 Description of traffic conditions in the Scheme area 13 2.4 Current transport issues 18 2.5 Data sources 20 2.6 ComMA data requirements 26 3 Model development 27 3.1 Introduction 27 3.2 Overview of the A428 strategic traffic model 27 3.3 The A428 strategic traffic model 28 3.4 Guidance applicable for development 31 3.5 A428 strategic traffic model development 32 3.6 Calibration and validation 37 3.7 Variable demand model 47 3.8 ComMA data requirements 48 4 Forecasting 50 4.1 Introduction 50 4.2 Assumptions 51 4.3 Forecast scenarios 54 4.4 Annual Average Daily Traffic (AADT) and other time period factors 56 4.5 Traffic forecasting outcomes 57 4.6 Operational models 82 4.7 ComMA Data Requirements 94 5 Economic appraisal 96 5.1 Economic appraisal approach 96 5.2 Scheme costs 102 5.3 Scheme benefits 104 5.4 Comparison of costs and benefits (including alternative growth scenarios) 116 5.5 ComMA data requirements 120 Planning Inspectorate Scheme Ref: TR010044 Application Document Ref: TR010044/APP/7.10 A428 Black Cat to Caxton Gibbet improvements Combined Modelling and Appraisal Report 6 Summary 122 6.1 The Scheme 122 6.2 Model development 122 6.3 Forecasts of future flows 123 6.4 Summary of economic appraisal 128 6.5 Consideration of results against scheme objectives 134 7 Glossary 135 Table of Figures Figure 1-1: Strategic Context ............................................................................................... 6 Figure 1-2: Local Context ..................................................................................................... 7 Figure 1-3: The Scheme ...................................................................................................... 8 Figure 2-1: Road Network in the vicinity of the Scheme .................................................... 12 Figure 2-2: Average Annual Daily Flow.............................................................................. 14 Figure 2-3: Daily Traffic Profile on A428 between Wyboston and Barford Road ................ 15 Figure 2-4: Daily Traffic Profile on A428 between Cambridge Road and Eltisley .............. 15 Figure 2-5: Observed Accident Locations (2011 – 2018) ................................................... 19 Figure 2-6: Depiction of Strategic Journey Time Routes for Model Validation ................... 24 Figure 2-7: Competing Journey Time Routes for Model Validation .................................... 25 Figure 3-1: Regional Traffic Model (RTM) Suite Design .................................................... 29 Figure 3-2: A428 Strategic Traffic Model Network Coding Level of Detail ......................... 30 Figure 3-3: Boundary of Area of Detailed Modelling .......................................................... 32 Figure 3-4: Zone System for Area of Detailed Modelling (AoDM) ...................................... 33 Figure 3-5: A428 Strategic Traffic Model Survey Cordon and Screenlines ........................ 34 Figure 3-6: SATURN ‘ME2’ Matrix Calibration Process ..................................................... 39 Figure 3-7: A428 Strategic Traffic Model Cordon and Screenlines .................................... 42 Figure 3-8: Demand Model Choice Hierarchy .................................................................... 48 Figure 4-1: Uncertainty Log Study Area ............................................................................. 51 Figure 4-2: Sections of Existing and Proposed Route........................................................ 59 Figure 4-3: Annual Average Daily Traffic (AADT), 2015 Base Year (Vehicles) .................. 65 Figure 4-4: Annual Average Daily Traffic (AADT), 2040 Do Minimum (Vehicles) .............. 66 Figure 4-5: Comparison of 2015 to 2040 DM - Percentage Change in AADT.................... 67 Figure 4-6: Annual Average Daily Traffic (AADT), 2040 Do Something (Vehicles) ............ 68 Figure 4-7: Annual Average Daily Traffic (AADT), 2040 Do Something Less 2040 Do Minimum (Vehicles) ........................................................................................................... 69 Figure 4-8: Comparison of 2040 DM to 2040 DS - Percentage Change in AADT .............. 70 Figure 4-9: Journey Time Routes (Long Distance) ............................................................ 71 Figure 4-10: Journey Time Routes (Local, Set 1) .............................................................. 72 Figure 4-11: Journey Time Routes (Local, Set 2) .............................................................. 72 Figure 4-12: Locations of the Local Modelled Junctions within the TA............................... 83 Figure 4-13: Locations of the Wide Area Modelled Junctions in the TAA .......................... 86 Figure 4-14: Summary of Impacts in Cambridgeshire ........................................................ 89 Figure 4-15: Summary of Impacts in Bedford Borough ...................................................... 92 Figure 4-16: Summary of Impacts in Central Bedfordshire ................................................ 94 Figure 5-1: Economics Sectors ........................................................................................ 101 Figure 5-2: Profile of Benefits 2025 to 2084 (£000s Discounted and Deflated to 2010) .. 106 Planning Inspectorate Scheme Ref: TR010044 Application Document Ref: TR010044/APP/7.10 A428 Black Cat to Caxton Gibbet improvements Combined Modelling and Appraisal Report Figure 5-3: Percentage of Total Journey Time / VOC benefits by Sector Origin .............. 109 Table of Tables Table 1-1: Client Scheme Requirements ............................................................................. 8 Table 2-1: Journey Time between Black Cat and Caxton Gibbet ...................................... 16 Table 2-2: Personal Injury Accidents by Severity and Year ............................................... 17 Table 2-3: Personal Injury Accidents by Route and Year................................................... 17 Table 2-4: Personal Injury Accidents Recorded as Serious in Severity by Scheme Area .. 17 Table 2-5: Observed Accidents and National Average Accidents ...................................... 19 Table 2-6: Sources of Existing Data and Use .................................................................... 20 Table 2-7: Additional Survey Data for A428 Strategic Traffic Model .................................. 21 Table 2-8: ComMA Data Requirements Summary – Chapter 2 ......................................... 26 Table 3-1: Model User Classes and Vehicle Classes ........................................................ 31 Table 3-2: Values of Time and Vehicle Operating Costs ................................................... 36 Table 3-3: TAG Unit M3.1: Significance of Matrix Estimation Changes ............................. 40 Table 3-4: Performance of Calibration Screenlines - Model Version ‘a’ ............................. 42 Table 3-5: Performance of Validation Screenlines - Model Version ‘a’ .............................. 42 Table 3-6: Performance of Calibration Screenlines - Model Version ‘b’ ............................. 43 Table 3-7: Performance of Validation Screenlines - Model Version ‘b’ .............................. 43 Table 3-8: TAG Link Flow and Turning Movement Calibration/Validation Criteria and Acceptability Guidelines ..................................................................................................... 44 Table 3-9: Total Calibration and Validation Counts (All Vehicles) – AM ............................ 44 Table 3-10: Total Calibration and Validation Counts (All Vehicles) – IP ............................ 45 Table 3-11: Total Calibration and Validation Counts (All Vehicles) – PM........................... 45 Table 3-12: Highway Model Convergence Results ............................................................ 47 Table 3-13: ComMA Data Requirements Summary – Chapter 3 ....................................... 49 Table 4-1: Summary of Forecast Scenarios ....................................................................... 56 Table 4-2: Light Vehicle Expansion Factors ....................................................................... 57 Table 4-3: Heavy Vehicle Expansion Factors ...................................................................