A14 Cambridge to Huntingdon Improvement Scheme
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A14 CAMBRIDGE TO HUNTINGDON IMPROVEMENT SCHEME DEVELOPMENT CONSENT ORDER - EXAMINATION Representation on Local Traffic Impacts By Cambridgeshire County Council Shire Hall, Castle Hill, Cambridge, CB3 0AP 2 September 2015 A14 Cambridge to Huntingdon Development Consent Order Written Representation on Local Traffic for Deadline 8 CONTENTS CONTENTS 2 1. INTRODUCTION 3 2. CHARM TRAFFIC MODEL 4 3. LOCAL TRAFFIC IMPACTS 6 3.2 Local Impact Report 7 4. SPECIFIC ISSUES 8 4.2 B1514 Brampton Road 8 4.3 Hinchingbrooke 8 4.4 Spittals 9 4.5 Galley Hill 9 5. ADDITIONAL WORK 10 6. MONITORING 12 7. INTERACTION WITH OTHER DEVELOPMENTS 13 7.1 Northstowe 13 7.2 A428 13 APPENDIX A - EXISTING NORTHSTOWE MONITORING 16 APPENDIX B – ADDITIONAL MONITORING LOCATIONS 18 APPENDIX C – ROAD CLOSURE GUIDELINES 19 APPENDIX D – SYSTRA REPORT 25 Page 2 A14 Cambridge to Huntingdon Development Consent Order Written Representation on Local Traffic for Deadline 8 1. INTRODUCTION 1.1.1 This Written Representation is in respect of Local Traffic Impacts and supersedes Chapter 10 of the County Council’s previous written representation (REP3-006) 1.1.2 This Written Representation, in respect of the A14 Cambridge to Huntingdon Improvement Scheme (the Scheme) Development Consent Order (the Order or DCO), is made in accordance with the Infrastructure Planning (Examination Procedure) Rules 2010, Rule 10. It must be read in conjunction with the Local Impact Report submitted for Deadline 8. 1.1.3 The Local Impact Report presents local traffic impacts and recommendations for mitigation. Information in the Local Impact Report is generally not repeated in this document. This document makes supporting and additional representations on local traffic matters. 1.1.4 The supporting report from Systra is in Appendix D Page 3 A14 Cambridge to Huntingdon Development Consent Order Written Representation on Local Traffic for Deadline 8 2. CHARM TRAFFIC MODEL 2.1.1 In this representation the following terms are used: CHARM3A – The revised traffic model submitted at Deadline 2 CHARM3A + LIT – The CHARM3A model plus local impact testing – considered by the County Council to be core modelling for the purposes of assessing impacts on local roads CHARM3A + LIT + S2 – The CHARM3A model plus local impact testing and sensitivity test 2 as detailed in REP6-002 – considered by the County Council to be more representative of the local road network and to better reflect typical journey times on the existing A14. 2.1.2 The County Council has made previous representations on the matter of Highways England’s traffic modelling. These are set out in REP3-006 (section 10), REP4-006, and REP7-005. The principal position of the County Council has been that Highways England has not sufficiently considered impacts of the A14 Cambridge to Huntingdon scheme (the Scheme) on the local road network. The County Council and its partner local authorities did not have full confidence in the predicted changes in traffic on the local network, due to weak validation and concerns over the model itself. 2.1.3 At Deadline 6 Highways England submitted the Local Traffic Impact Report (REP6—002), which presented the results of local impact testing of changes to the core modelling requested by the County Council and other local authorities, together with a sensitivity test. These were: Revisions to the allocation and distribution of Base Year demand; Correction to tidal permitted movements on Silver Street, Cambridge; Revisions to future year infrastructure assumptions; Revisions to the coding of Spittals Interchange; and Revisions to scheme coding in the vicinity of Dry Drayton. 2.1.4 In respect of the local impact testing this is core modelling as it resolved factual concerns regarding coding of the model. The CHARM 3A + LIT modelling, except for journey times on the existing A14, now correctly represents the base network, trip allocations, and future schemes. 2.1.5 However, concerns remained over the use of median as opposed to mean journey times on the existing A14. The use of median is entirely valid, but there was concern that the Page 4 A14 Cambridge to Huntingdon Development Consent Order Written Representation on Local Traffic for Deadline 8 values of journey time did not reflect the actual levels of delay and congestion experienced on the existing A14. The County Council asked Highways England to run a sensitivity test of using mean rather than median journey times on the existing A14. 2.1.6 In consequence, the CHARM3A + LIT traffic model alone potentially underrepresents the amount of traffic using alternative routes to avoid the A14. This manifests as traffic using local roads to join the A14 closer to Cambridge, and as traffic making alternative route choices. The view of the County Council is that CHARM3A + LIT + S2 is more representative of local road changes resulting from the Scheme. However, since the method in Sensitivity Test 2 manipulated speed flow curves rather than changing journey time coding, it is accepted as being a sensitivity test. 2.1.7 The County Council remains concerned over the matter of apparent growth in trips into and out of Cambridge City Centre. It appears that there is insufficient congestion and delay within the model. This appears to allow some traffic to route through central Cambridge in preference to using outer orbital roads such as the M11. This is counter- intuitive based on local knowledge and experience. The County Council has satisfied itself that this appears to be a feature of the model, rather than a real predicted change. 2.1.8 With respect to validation, this remains a concern in respect of the local road network. However, the County Council is satisfied that the routing changes post A14 are plausible and the proportionate change reasonable. Less reliance should, however, be placed on the exact quantum of change in areas with weak validation. 2.1.9 On balance, the County Council is of the opinion that the modelling reported in Highways England’s Local Traffic Impact Report can be used to assess the traffic impacts of the A14 on the local road network, provided account is taken of the Sensitivity Test 2 output. 2.1.10 The County Council notes that the model is specifically for use with the A14 Cambridge to Huntingdon project. It is primarily a strategic road model and detailed modelling confined to a relatively narrow strip along the A14. In view of the weak validation on the local road network in several areas, the CHARM3A + LIT model should not be used for any other road project or development without further work. Page 5 A14 Cambridge to Huntingdon Development Consent Order Written Representation on Local Traffic for Deadline 8 3. LOCAL TRAFFIC IMPACTS 3.1.1 In general, the impact of the A14 is beneficial to the local road network, reducing traffic compared to the predicted level of traffic in the Do Minimum scenarios as this traffic is predicted to occur without the scheme. There are, however, areas where there is a negative impact and traffic on the local road network increases. The County Council considers an increase of traffic on the local road network caused by implementation of the A14 scheme to be an impact of the scheme, even if the location is some distance from the new road. The impact of congestion on the A14 is widely felt as traffic uses alternative routes to avoid congestion. Examples of this are: Traffic from the St Neots area has a more direct route via the B1043 and Godmanchester to the A14. However, some traffic uses unclassified roads through Graveley to reach the A1198, then Graveley Way to access the B1040 and A14. This is in Highways England’s Local Traffic Impact Report (REP6-002) on Figure 4.13. Local traffic from the Hilton area has a direct route to the A14 via the B1040. However, some traffic uses the unclassified Hilton Road to reach the A14 closer to Cambridge at Fen Drayton. This is in Highways England’s Local Traffic Impact Report on Figure 4.16. Some traffic from Huntingdon to St Ives and beyond currently chooses to use the A1123 instead of the A14; with the scheme, it uses the de-trunked A14 and the A1096. This is in Highways England’s Local Traffic Impact Report on Figure 4.14. Traffic from St Ives routes down the B1040 to Hilton, uses Graveley Way to reach the A1198 and Godmanchester. With scheme, this traffic uses the de- trunked A14. This is in Highways England’s Local Traffic Impact Report on Figure 4.17. Some traffic uses Low Road to reach the A14 via Fenstanton, to avoid the junction at Galley Hill. This is in Highways England’s Local Traffic Impact Report on Figure 4.15. Traffic from Cambourne currently routes up through Knapwell and Conington to reach the A14 at Fen Drayton/Fenstanton. With scheme, this traffic routes up the A1198 instead. This is in Highways England’s Local Traffic Impact Report on Figure 4.18. Page 6 A14 Cambridge to Huntingdon Development Consent Order Written Representation on Local Traffic for Deadline 8 3.1.2 This amply demonstrates that the impact of congestion on the A14 influences traffic movements well outside the immediate corridor. In all cases, traffic is using more minor or unclassified roads with the aim of joining the existing A14 at a point closer to Cambridge. In 2001-2003 the DfT made available £4.5m of funding to provide traffic calming in villages along the A14 Huntingdon to Cambridge corridor in recognition of this accepted problem. 3.1.3 It is not, therefore, at all unexpected that with the construction of the new A14, traffic reverts to using more direct routes to access the Strategic Road Network at the earliest opportunity.