Transport Study
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Poole Local Plan Transport Study July 2017 Contents Executive Summary ......................................................................................................................... 3 1. Introduction ................................................................................................................................ 6 2. Context ...................................................................................................................................... 7 3. SATURN Modelling - Methodology and Results ........................................................................ 8 4. Average vehicle Speeds and Queueing .................................................................................. 10 5. Adding Mitigation - Strategic Sustainable Transport Interventions and A31 Link Road ........... 12 6. The Poole Local Plan - Updated Transport Policy ................................................................... 14 7. Conclusion ............................................................................................................................... 15 Appendix 1 – Network Statistics - Tables ...................................................................................... 17 Appendix 2 - Summary Network Statistics ..................................................................................... 22 Appendix 3 – Hotspot Analysis ...................................................................................................... 29 Appendix 4 - Provisional Mitigation Measures ............................................................................... 31 Appendix 5 - Additional Infrastructure Requirements (Provisional)…………………………………..40 Appendix 6 - Glossary……………………………………………………………………………………..44 Appendix 7 - Dorset County Council SATURN Modelling Report…………………………………….45 Purpose This report summarises the transport context, the modelling methodology, results, implications and new policies of the Poole Local Plan Pre-Submission Draft. It also describes potential measures which could mitigate the impact of increased traffic from general background growth and growth arising from the Poole Local Plan. Poole Local Plan. Transport Study, August 2017 2 Executive Summary Poole has a housing requirement of 14,200 homes to be delivered by 2033 - 710 homes per year. This is a significant increase compared to the current adopted requirement of 10,000 homes from 2006 - 2026, which equates to 500 homes per year. The focus for growth in the Draft Poole Local Plan is to direct the majority of development to the most accessible parts of the town such as the town centre, with significant redevelopment providing 6,000 new homes and supporting leisure, retail and commercial development in balance with protection of the harbour and other urban infill of 6,900 homes. However two urban extensions into the green belt are identified in the draft plan as necessary for the Council to meet its full housing need. This new housing requirement, if delivered, will have impacts upon the Poole transport network that will require investment in a programme of sustainable transport and other highway mitigation works. The Borough of Poole’s first step in developing an evidence base to inform the draft plan was to commission Dorset County Council (DCC) to undertake a strategic transport modelling exercise using an area-wide transport model (the South East Dorset Transport Model) that forecasts future traffic levels based on government mandated assumptions about growth. This model is managed by DCC and owned by all South East Dorset authorities. The model does not factor in impacts like sustainable transport mitigation measures or potential changes in travel behaviour e.g. increased home working, which are likely to occur through delivery of programmed projects included in Local Transport Plan 3 (LTP3) for Bournemouth, Poole and Dorset, and so provides a snapshot of a future growth scenario with maximum levels of development and no mitigation, to show what could happen if a ‘Do Nothing’ approach is taken. This represents the first part of the exercise in determining how to accommodate growth in the Borough from a transport perspective. On this basis, the transport model forecasts that, without any mitigation, the Poole network in 2033 will experience approximately 34% more vehicle trips than in 2012 (2012 is the last time the model was validated). Growth in traffic between 2012 and 2016 in Poole was approximately 3% so the model outputs are not undermined by growth between 2012 and now. The 34% includes all of the planned growth remaining to be delivered within the current adopted Core Strategy to 2026. It is evident in this regard that both the existing planned and proposed additional growth will have to contribute significantly towards delivering a step change in travel behaviour through sustainable transport and highways mitigation measures. Adding the additional sites from the draft Poole Local Plan, the model predicts 36.8% more trips than in 2012, i.e. an additional 2.5%. This suggests that whilst the proposed draft Poole Local Plan growth in isolation does not significantly worsen the situation over existing planned growth, significant transport interventions including those established in LTP3 are necessary to ensure the full growth proposed in the draft plan can be accommodated within the transport network. Some of the predicted rises will be absorbed into areas of the network that have spare capacity but some are concentrated in areas that already experience congestion and, as already identified in LTP3, will require mitigation. As the rise in trips is not spread equally across the network it is more useful to consider changes in queueing and vehicle speeds as these show impacts on journey times and potential constraints on quality of life and economic growth. The modelling results suggest that, without any mitigation, by 2033 general population and economic growth will bring about considerable increases in queueing, in the worst cases by a factor of 20 and reductions in average vehicle speeds by approximately 25%. The additional residential sites in the draft Plan do exacerbate this in some localised hotspots and a focussed programme of mitigation will be required to minimise the impacts. It is worth noting that based Poole Local Plan. Transport Study, August 2017 3 on trends captured in the 2011 census and including growth in the proposed Plan, the modelling results suggest travel destinations are not solely concentrated in Poole and Bournemouth town centres, with many travel destinations located outside the Borough and thus not easy to get to by public transport. Large volumes of traffic travelling mainly to Poole town centre are not forecast. A key part of the solution to this in the medium to longer term will be to support the Poole and South East Dorset economy (as the draft plan seeks to do) to reduce the need to travel to further-afield locations. Significant further work is required to build on LTP3 policy proposals to ensure Poole can deliver the homes to facilitate growth, whilst protecting our environment and local air quality. The next step in the SATURN modelling exercise was to assess how growth could be accommodated by incorporating strategic but as yet provisional transport interventions into the SATURN modelling. That generally, the most congested corridors are located around Ringwood Road and Wallisdown Road. This allowed for forecasts of the impact of potential major sustainable transport interventions like Park and Ride and a Quality Bus Corridor on traffic and also includes modelling the impacts of a new link road. Results from the SATURN modelling exercise suggest that delivery of park and ride schemes, a Quality Bus Corridor (QBC) and an A31 Link Road reduces the overall (network wide) queueing and delays to levels below the 2033 background growth only case and mitigates some of the increased, localised congestion around the Ringwood Road and Wallisdown Road corridors. However, even with incorporating strategic transport projects and a full A31 link road, queueing levels are still forecast to be up to 20 times higher than the 2012 base year due to the high existing planned and other background growth. The modelling results also suggest that an A31 link would alleviate localised congestion around Bearwood Roundabout and Ringwood Road. However as a new trip attractor at Mannings Heath roundabout on the Dorset Way is created through a new A31 link, new trips and thus congestion would be generated there. While this provides some understanding of the impacts of a new link road, it is clear further detailed work on the localised network is required to ascertain the full impacts of an A31 Link Road and other strategic projects. The SATURN results show that even with the strategic sustainable transport interventions and an A31 link road, the worst hotspots on Ringwood Road which are south of the Alderney Roundabout are still predicted to be over capacity. The modelling work has produced outputs which allow for a detailed ‘Hotspot analysis’ of the worst performing junctions that would experience the worst congestion. This will inform development of long term strategic investment in infrastructure in the form of an ‘Infrastructure Delivery Plan (IDP)’ that will be based on a robust evidence base. In order to estimate how the forecast increases in traffic can be mitigated; the Borough has also identified provisional improvements to the highway network that will increase capacity at key junctions