A303 Stonehenge Amesbury to Berwick Down Scheme Assessment Report Volume 1
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A303 Stonehenge Amesbury to Berwick Down Scheme Assessment Report Volume 1 September 2017 A303 Stonehenge - Amesbury to Berwick Down | HE551506 Table of contents Chapter Pages Foreword 1 Executive Summary 2 1. Introduction 12 1.1 Purpose of this Report 12 1.2 Scheme Context 13 1.3 Scheme History 15 1.4 Structure of this Report 22 2. Existing Conditions and Need for the Scheme 25 2.1 Introduction 25 2.2 Statement of the Problem 27 2.3 Engineering Conditions 40 2.4 Highways Network 46 2.5 Environmental 50 2.6 Existing Social and Distributional Conditions 58 2.7 Corridor 61 2.8 Do-Nothing Consequences 61 3. Planning Factors 65 3.1 Introduction 65 3.2 Planning Brief (CSRs) 65 3.3 UK Legislation and European Directives 67 3.4 National Policy 69 3.5 Other Relevant Policy and Strategy 71 3.6 Local Policy 73 4. Option Identification (PCF Stage 1) 76 4.1 Options Identification 76 4.2 Initial Corridor appraisal – Design Fix A 76 4.3 Development of route options within corridors – Design Fix B 80 4.4 Initial route options appraisal – Design Fix C 81 4.5 Further route options appraisal 85 4.6 Appraisal summary 91 4.7 Overall Summary 91 5. Public Consultation Summary 93 5.1 Introduction 93 5.2 Scheme Proposals Presented for Consultation 93 5.3 Consultation Arrangements 94 5.4 Consultation Response 94 5.5 Key considerations 96 6. Option Selection (PCF Stage 2) 98 6.1 Introduction 98 A303 Stonehenge - Amesbury to Berwick Down | HE551506 6.2 Development and Sifting of Modified Route Options 98 6.3 Better performing Modified Route Options for appraisal 108 7. Engineering and Safety Assessment 110 7.1 Introduction 110 7.2 Engineering Design and Assessment 110 7.3 Safety Assessment - Impact on Road User 124 7.4 Safety Assessment - Impact during Construction, Maintenance, Operation and Demolition (CDM) 130 7.5 Summary and Conclusions 132 8. Client Scheme Requirements and Policy Assessment 134 8.1 Introduction 134 8.2 Assessment methodology 134 8.3 Assessment 135 8.4 Summary and conclusions 140 9. Traffic Assessment 141 9.1 Introduction 141 9.2 Traffic Modelling Methodology 142 9.3 Analysis of Scheme Performance 157 10. Economic Assessment 165 10.1 Introduction 165 10.2 Overview 165 10.3 Presentation of results 167 10.4 Economic Appraisal Approach 168 10.5 Results 175 10.6 Variable Cost, Demand and Cultural Heritage Valuation Sensitivity Tests 180 10.7 Economic assessment conclusions 186 11. Operational Assessment 187 11.1 Introduction 187 11.2 Scheme's Operating Regime 187 11.3 Driver Compliance 189 11.4 Summary and Conclusions 190 12. Technology and Maintenance Assessment 191 12.1 Introduction 191 12.2 Option Design Implications of ITS Systems 191 12.3 Maintenance and Repair Strategy for Civils 193 12.4 Maintenance and Repair Strategy for Technology 194 12.5 Summary and Conclusions 195 13. Environmental Assessment and Design 196 13.1 Introduction 196 13.2 Assessment Methodology 196 13.3 Assessment Results 204 13.4 Assessment Conclusions 224 A303 Stonehenge - Amesbury to Berwick Down | HE551506 14. Social Assessment 245 14.1 Introduction 245 14.2 Assessment Methodology 245 14.3 Assessment Results 251 14.4 Summary and Conclusions 255 15. Distributional Impact Assessment 257 15.1 Introduction 257 15.2 Assessment methodology 257 15.3 Assessment Results 259 15.4 Summary and Conclusions 262 16. Appraisal Summary 264 16.1 WebTAG Appraisal Summary Introduction 264 16.2 Appraisal Summary Tables (ASTs) 270 16.3 Key Considerations from Consultation 271 16.4 Interim Ranking against Key Considerations from Consultation 275 17. Conclusions and Recommendations 278 17.1 The Recommended Preferred Route 280 Abbreviations List 282 Glossary 286 References 300 Appendices i Appendix A Existing Conditions ii A.1 Geology Mapping ii A.2 Existing Public Utilities iii A.3 Environmental Constraints iv Appendix B Option Identification v B.1 Historical Route Options v B.2 Corridors Identified vi B.3 Highest Performing Corridors vii B.4 Routes within Highest Performing Corridors viii B.5 Routes for Consultation ix Appendix C Option Selection x C.1 Modified Route Options and Best Performing Modified Route Options for Appraisal x C.2 Stage 2 Route Options for Appraisal xi Appendix D Client Scheme Requirements (CSRs) and Policy Assessment xii D.1 CSR Assessment Tables xiii D.2 Policy Assessment Tables xxx D.3 National and Local Policy Objectives ccxxvii Appendix E Historic Environment Assessment ccxxxv Appendix F Appraisal Summary Tables ccxxxvi Appendix G Recommended Preferred Route ccxxxvii A303 Stonehenge - Amesbury to Berwick Down | HE551506 Table of Figures Figure 1 Options identification process………………………………………………...……3 Figure 2 Consultation proposals for the A303 Stonehenge……………………….………4 Figure 3 Modified route options …………………………………………………………...…7 Figure 4 Recommended Preferred Route …………………………………………………11 Figure 1-1 A303/A30 trunk route and Amesbury to Berwick Down scheme .................... 13 Figure 1-2 Schemes to deliver an Expressway to the South West ................................. 15 Figure 1-3 Examples of alternative routes considered [3] ............................................... 16 Figure 1-4 Scheme published in 2003 for A303 Stonehenge Improvement [3] ............... 19 Figure 1-5 Plan showing location of relocated Stonehenge Visitor Centre ..................... 20 Figure 1-6 Highways England's Major Projects Lifecycle [14] ......................................... 22 Figure 2-1 A303 Stonehenge: Amesbury to Berwick Down - study area ....................... 25 Figure 2-2 Proximity of Stonehenge to the A303 ............................................................ 26 Figure 2-3 Distribution of traffic on the A303 at Stonehenge .......................................... 27 Figure 2-4 A303 – Westbound daily traffic by day and month ......................................... 29 Figure 2-5 A303 – Eastbound daily traffic by day and month .......................................... 29 Figure 2-6 A303 through traffic (Hampshire border to Winterbourne Stoke) ................... 32 Figure 2-7 Cumulative traffic flows diverting from A303 at Stonehenge.......................... 33 Figure 2-8 A303 – Eastbound Average Daily Traffic (ADT) by hour and month (March, July, August and October only) ......................................................................................... 34 Figure 2-9 A303 – Westbound Average Daily Traffic (ADT) by hour and month (March, July, August and October only) ......................................................................................... 34 Figure 2-10 Average journey times: Exeter to London (Westbound) ............................ 36 Figure 2-11 Average journey times: London to Exeter (Eastbound) .............................. 36 Figure 2-12 Eastbound journey times (minutes) by time of day (August 2014), Winterbourne Stoke to Hampshire border ......................................................................... 37 Figure 2-13 Westbound journey times (minutes) by time of day (August 2014), Hampshire border to Winterbourne Stoke ........................................................................................... 37 Figure 2-14 Accident section locations .......................................................................... 38 Figure 2-15 Distribution of Accidents between Amesbury and Berwick Down ............... 39 Figure 4-1 Options identification process ........................................................................ 76 Figure 4-2 Historical Route Options ................................................................................ 77 Figure 4-3 Corridors Identified ........................................................................................ 78 Figure 4-4 Best performing corridor options (Design Fix A) ............................................ 80 Figure 4-5 Corridor D route options for initial appraisal ................................................... 83 Figure 4-6 Corridor F route options for initial appraisal ................................................... 85 Figure 4-7 Route options for further appraisal ................................................................ 86 Figure 5-1 A303 Stonehenge: Amesbury to Berwick Down consultation proposals ........ 93 Figure 5-2 Views on scheme proposals from questionnaire responses .......................... 95 Figure 5-3 Preferences for Winterbourne Stoke Bypass ........................................ 96 Figure 6-1 Preferred Route option selection process ...................................................... 98 Figure 9-1 Area of Detailed Modelling ........................................................................... 143 Figure 9-2 SATURN Highway Modelling Process ......................................................... 148 Figure 9-3 Expressway to the South West .................................................................... 151 Figure 9-4 Overview of Forecasting Process ................................................................ 153 Figure 9-5 2041 PM Peak Forecast Traffic Flows Option 1Na ...................................... 159 A303 Stonehenge - Amesbury to Berwick Down | HE551506 Figure 9-6 2041 PM Peak Forecast Traffic Flows – Difference from Do Minimum Option 1Na 160 Figure 9-7 2041 PM Peak Forecast Traffic Flows Option 1Sa ...................................... 161 Figure 9-8 2041 PM Peak Forecast Traffic Flows – Difference from Do Minimum Option 1Sa .................................................................................................................................. 162 Figure 9-9