A417 Missing Link Technical Appraisal Report February 2018 A417 Missing Link Technical Appraisal Report Contents Page Executive summary ......................................................................................................... 10 Purpose of this report......................................................................................................... 10 History of the scheme ........................................................................................................ 10 Challenges and opportunities ............................................................................................ 11 Objectives for the A417 Missing Link ................................................................................. 12 Option identification and sifting .......................................................................................... 12 Full assessment and appraisal .......................................................................................... 14 Conclusions ....................................................................................................................... 18 1. Introduction ............................................................................................................ 21 1.1 Purpose of this report ............................................................................................... 21 1.2 Scheme context ....................................................................................................... 21 1.3 History of the scheme .............................................................................................. 22 2. Planning brief ......................................................................................................... 26 2.1 Client scheme requirements .................................................................................... 26 2.2 Key stakeholder objectives ...................................................................................... 28 3. Existing conditions ................................................................................................ 31 3.1 General .................................................................................................................... 31 3.2 Description of the locality ......................................................................................... 31 3.3 Existing highway network ......................................................................................... 32 3.4 Traffic ....................................................................................................................... 33 3.5 Accident and journey time reliability ......................................................................... 37 3.6 Topography .............................................................................................................. 41 3.7 Land use, property and industry ............................................................................... 44 3.8 Climate ..................................................................................................................... 44 3.9 Road drainage ......................................................................................................... 46 3.10 Geology ................................................................................................................ 47 3.11 Mining ................................................................................................................... 48 3.12 Public utilities ........................................................................................................ 49 3.13 Environmental status (designated areas) ............................................................. 50 3.14 Environment.......................................................................................................... 51 Page 1 A417 Missing Link Technical Appraisal Report 3.15 Accessibility .......................................................................................................... 56 3.16 Integration ............................................................................................................. 57 4. Planning factors ..................................................................................................... 68 4.1 Legislation and guidance - International, European and national ............................. 68 4.2 Legislation and guidance - national .......................................................................... 74 4.3 Legislation and guidance - local ............................................................................... 79 4.4 Environmental Impact Assessment Determination – Screening ............................... 82 5. Options development ............................................................................................ 83 5.1 Initial option generation ............................................................................................ 83 5.2 Escarpment corridors ............................................................................................... 85 5.3 Escarpment corridor A ............................................................................................. 86 5.4 Escarpment corridor B ............................................................................................. 87 5.5 Escarpment corridor C ............................................................................................. 89 5.6 Escarpment corridor D ............................................................................................. 91 5.7 Escarpment corridor E ............................................................................................. 92 6. Options sifting ........................................................................................................ 93 6.1 Sifting methodology ................................................................................................. 93 6.2 Step 2 – Engineering assessment ........................................................................... 93 6.3 Step 3 – Early Assessment and Sifting Tool Plus assessment ................................ 96 6.4 Step 4 – Value for money and affordability assessment ........................................ 101 6.5 Conclusions ........................................................................................................... 103 7. Description of options ......................................................................................... 104 7.1 General .................................................................................................................. 104 7.2 Tunnel design ........................................................................................................ 104 7.3 Option 3 ................................................................................................................. 108 7.4 Option 12 ............................................................................................................... 111 7.5 Option 21 ............................................................................................................... 115 7.6 Option 24 ............................................................................................................... 118 7.7 Option 29 ............................................................................................................... 121 7.8 Option 30 ............................................................................................................... 125 7.9 Options’ statutory undertakers’ estimates .............................................................. 128 7.10 Option estimates ................................................................................................. 129 7.11 Conclusions ........................................................................................................ 130 Page 2 A417 Missing Link Technical Appraisal Report 8. Traffic analysis ..................................................................................................... 131 8.1 Traffic data ............................................................................................................. 131 8.2 Traffic analysis ....................................................................................................... 131 8.3 Road layout and standards .................................................................................... 136 8.4 Conclusions ........................................................................................................... 139 9. Economic assessment ........................................................................................ 141 9.1 Introduction ............................................................................................................ 141 9.2 Application of economic assessment methods ...................................................... 141 9.3 Conclusions ........................................................................................................... 145 10. Safety assessment ............................................................................................... 148 10.1 Impact on road user – strategic safety action plan.............................................. 148 10.2 Buildability and maintenance .............................................................................. 163 10.3 Effective construction management – Construction (Design and Management) Regulations 2015 ............................................................................................................