Bridgwater Transport Options Infrastructure Options Technical Report
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BRIDGWATER TRANSPORT OPTIONS INFRASTRUCTURE OPTIONS TECHNICAL REPORT October 2016 BRIDGWATER TRANSPORT OPTIONS INFRASTRUCTURE OPTIONS TECHNICAL REPORT Somerset County Council Project no: 62102386 Date: October 2016 WSP | Parsons Brinckerhoff Riverside Chambers Castle Street Taunton TA1 4AP www.wsp-pb.co.uk iv TABLE OF CONTENTS EXECUTIVE SUMMARY .............................................................................1 1 PROJECT BACKGROUND ..........................................................1 1.1 Introduction ................................................................................... 1 1.2 Model History ................................................................................ 1 1.3 COntext ......................................................................................... 1 1.4 STUDY OBJECTIVES ................................................................... 2 2 FORECAST DEMAND ..................................................................3 2.1 Model overview.............................................................................. 3 2.2 Demand Forecast Methodology ..................................................... 3 2.3 Trip Generation.............................................................................. 4 2.4 Background Growth ....................................................................... 7 2.5 HGV Growth .................................................................................. 7 2.6 Distribution .................................................................................... 7 2.7 Highway Assignment ..................................................................... 8 3 INFRASTRUCTURE SCENARIOS ...............................................9 3.1 Do Minimum infrastructure ............................................................. 9 3.2 Do something infrastructure ........................................................... 9 4 ASSIGNMENT RESULTS ..........................................................11 4.1 Forecast Scenarios .......................................................................11 4.2 ASSIGNMENT Convergence ........................................................11 4.3 Network Wide Statistics ................................................................12 4.4 Journey time analysis ...................................................................14 4.5 DO Minimum Scenario - Traffic Impacts ........................................15 4.6 Do Something Northern Bypass – Traffic Impacts .........................18 4.7 Do Something Eastern distributor road – Traffic Impacts ...............22 4.8 Do Something Southern bypass – Traffic Impacts .........................28 4.9 DO SOMETHING All Options combined – Traffic Impacts .............33 5 CONCLUSION ............................................................................41 5.1 Summary of process .....................................................................41 5.2 Summary of Findings ....................................................................41 5.3 Limitations ....................................................................................42 5.4 Further work .................................................................................43 Bridgwater Transport Options - Infrastructure Options Technical Report WSP | Parsons Brinckerhoff Somerset County Council Project No 62102386 v TABLES TABLE 2-1: PROPOSED DEVELOPMENTS – TRIP GENERATION (PCU) ........................ 6 TABLE 2-2: MOTORWAY SERVICES AREA TRIPS .......................................................... 6 TABLE 4-1: WEBTAG CONVERGENCE CRITERIA ......................................................... 11 TABLE 4-2: JOURNEY ROUTES START AND END POINTS .......................................... 15 TABLE 4-3: JUNCTIONS WHICH ARE OVERCAPACITY IN THE DO MINIMUM SCENARIO ..................................................................................... 16 TABLE 4-4: OVERCAPACITY JUNCTIONS IN THE DO SOMETHING NORTHERN BYPASS OPTION ........................................................................... 20 TABLE 4-5: JOURNEY TIME RESULTS FOR NORTHERN BYPASS DO SOMETHING SCENARIO AND ALTERNATIVE ROUTE ....................................... 22 TABLE 4-6: OVERCAPACITY JUNCTIONS IN THE DO SOMETHING EASTERN DISTRIBUTOR ROAD OPTION SCENARIO ................................... 25 TABLE 4-7: JOURNEY TIME RESULTS FOR EASTERN DISTRIBUTOR ROAD SCENARIO AND ALTERNATIVE ROUTE 1 .................................... 27 TABLE 4-8: JOURNEY TIME RESULTS FOR EASTERN DISTRIBUTOR ROAD SCENARIO AND ALTERNATIVE ROUTE 2 .................................... 28 TABLE 4-9: OVERCAPACITY JUNCTIONS IN THE DO SOMETHING SOUTHERN BYPASS OPTION SCENARIO ........................................................ 31 TABLE 4-10: JOURNEY TIME RESULTS FOR SOUTHERN BYPASSS SCENARIO AND ALTERNATIVE ROUTE .......................................................... 32 TABLE 4-11: OVERCAPACITY JUNCTIONS IN THE DO SOMETHING ALL INFRASTRUCTURE OPTION COMBINED SCENARIO................... 35 TABLE 4-12: NORTHERN BYPASS AND ALTERNATIVE ROUTE JOURNEY TIME RESULTS ....................................................................................... 37 TABLE 4-13: EASTERN DISTRIBUTOR ROAD AND FIRST ALTERNATIVE ROUTE JOURNEY TIME RESULTS............................................................. 38 TABLE 4-14: EASTERN DISTRIBUTOR ROAD AND SECOND ALTERNATIVE ROUTE JOURNEY TIME RESULTS............................................................. 39 TABLE 4-15: SOUTHERN BYPASS AND ALTERNATIVE ROUTE JOURNEY TIME RESULTS ....................................................................................... 40 TABLE 5-1: MAIN INFRASTRUCTURE RESULTS - INDIVIDUAL ASSESSMENT............ 42 FIGURES FIGURE 2-1: PROCESS TO CREATE DEMAND MATRICES ............................................ 4 FIGURE 2-2: DEVELOPMENT SITE LOCATIONS USED IN INFRASTRUCTURE TESTING .......................................................................................... 5 FIGURE 3-1: LOCATION OF PROPOSED INFRASTRUCTURE ...................................... 10 FIGURE 4-1: TOTAL TRAVEL TIME (PCU HR)................................................................ 12 FIGURE 4-2: AVERAGE SPEED (KPH) ........................................................................... 13 FIGURE 4-3: AVERAGE SPEED IN BRIDGWATER (KPH) .............................................. 14 Bridgwater Transport Options - Infrastructure Options Technical Report WSP | Parsons Brinckerhoff Somerset County Council Project No 62102386 vi FIGURE 4-4: JOURNEY ROUTES ................................................................................... 15 FIGURE 4-5: JUNCTIONS TO BE OVERCAPACITY IN THE DO MINIMUM SCENARIO.. 17 FIGURE 4-6: ACTUAL FLOW DIFFERENCE BETWEEN DS - NORTHERN BYPASS OPTION AND DM - AM ................................................................... 18 FIGURE 4-7: ACTUAL FLOW DIFFERENCE BETWEEN DS - NORTHERN BYPASS OPTION AND DM - PM ................................................................... 19 FIGURE 4-8: LOCATION PLAN FOR NORTHERN BYPASS OPTION ............................. 21 FIGURE 4-9: ACTUAL FLOW DIFFERENCE BETWEEN DS - EASTERN DISTRIBUTOR ROAD OPTION AND DM - AM................................ 24 FIGURE 4-10: ACTUAL FLOW DIFFERENCE BETWEEN DS - EASTERN DISTRIBUTOR ROAD OPTION AND DM - PM................................ 24 FIGURE 4-11: LOCATION PLAN FOR EASTERN DISTRIBUTOR ROAD OPTION .......... 26 FIGURE 4-12: ACTUAL FLOW DIFFERENCE BETWEEN DS - SOUTHERN BYPASS OPTION AND DM - AM ................................................................... 29 FIGURE 4-13: ACTUAL FLOW DIFFERENCE BETWEEN DS - SOUTHERN BYPASS OPTION AND DM - PM ................................................................... 30 FIGURE 4-14: LOCATION PLAN FOR SOUTHERN BYPASS OPTION............................ 31 FIGURE 4-15: ACTUAL FLOW DIFFERENCE BETWEEN DS - ALL INFRASTRUCTURE OPTION AND DM - AM .................................. 33 FIGURE 4-16: ACTUAL FLOW DIFFERENCE BETWEEN DS - ALL INFRASTRUCTURE OPTION AND DM - PM .................................. 34 FIGURE 4-17: LOCATION PLAN FOR ALL INFRASTRUCTURE OPTION ....................... 36 APPENDICES APPENDIX A CONVERGENCE RESULTS APPENDIX B DO SOMETHING SCENARIO - NORTHERN BYPASS OPTION SELECT LINK ANALYSIS APPENDIX C DO SOMETHING SCENARIO - EASTERN DISTRIBUTOR ROAD OPTION SELECT LINK ANALYSIS APPENDIX D DO SOMETHING SCENARIO – SOUTHERN BYPASS OPTION SELECT LINK ANALYSIS APPENDIX E DO SOMETHING SCENARIO – ALL INFRASTRUCTURE OPTION SELECT LINK ANALYSIS Bridgwater Transport Options - Infrastructure Options Technical Report WSP | Parsons Brinckerhoff Somerset County Council Project No 62102386 EXECUTIVE SUMMARY Based on a single demand scenario (based on potential Local Plan allocations) this study identifies the potential traffic benefit of constructing additional infrastructure around Bridgwater. Four potential infrastructure scenarios have been considered: a Northern Bypass; an Eastern Distributor Road; a Southern Distributor Road only; and implementation of all three infrastructure options. As would be expected, the implementation of all three infrastructure options in combination provided the greatest improvement to traffic by all measures considered within this report. Of the individual scenarios, the Northern Bypass and the Southern Bypass scenarios have very similar network wide improvements compared to the Do Minimum scenario. However the Southern Bypass scenario generally benefits local traffic whilst the Northern Bypass and Eastern