St Austell Transport Strategy Development Appendix B – Transport Strategy Review May 2017 St Austell Town Framework Transport Strategy Review EDG0362-R001 Revision No. 01 Date: 12/12/2013 CORMAC Consultancy CORMAC Western Region, Radnor Road, Scorrier, Redruth, Cornwall, TR16 5EH. St Austell Town Framework Transport Strategy Review Issue & Revision Record Revision Date Originator Checked Authorised Purpose of Issue Nature of Change 01 12/12/13 AJA / JF LM AJA First Issue If you would like this report in another format, please contact CORMAC Solutions Ltd Head Office Castle Canyke Road Bodmin Cornwall PL31 1DZ Prepared by Tel: 01872 323 313 Engineering Design Group Email: [email protected] www.cornwall.gov.uk/cormac This document has been prepared for the titled project or named part thereof and should not be relied upon or used for any other project without an independent check being carried out as to its suitability and prior written authority of Cormac Solutions Ltd being obtained. Cormac Solutions Ltd accepts no responsibility or liability for the consequences of this document being used for a purpose other than the purposes for which it was commissioned. Any person using or relying on the document for such other purposes agrees, and will by such use or reliance be taken to confirm his agreement to indemnify Cormac Solutions Ltd for all loss or damage resulting therefrom. Cormac Solutions Ltd accepts no responsibility or liability for this document to any party other than the person by whom it was commissioned. CORMAC Solutions Ltd Head Office, Castle Canyke Road, Bodmin, Cornwall, PL31 1DZ CONTENTS 1 INTRODUCTION 1 1.1 Overview 1 1.2 Project Scope 1 1.3 Report Structure 1 2 STRATEGIC TRANSPORT MODEL REVIEW 2 3 WEST CARCLAZE DEVELOPMENT TRAFFIC IMPACT 3 4 REVIEW TRANSPORT SCHEME PROPOSALS 5 5 REVIEW PUBLIC TRANSPORT PRIORITY MEASURES 6 6 EDGCUMBE TRIANGLE ANALYSIS 7 7 TREWHIDDLE FARM LINK ROAD ANALYSIS 8 8 CONCLUSION 9 1 INTRODUCTION 1.1 Overview 1.1.1 CORMAC Solutions Ltd (CSL) has been commissioned by Cornwall Council (CC) to review the St Austell Town Framework Transport Strategy in light of potential reductions in housing numbers proposed in the emerging Local Plan. 1.1.2 This review does not include detailed strategic or micro-level remodelling due to limitations in both timescale and budget. The review therefore makes a number of assumptions relating to potential development traffic generation, distribution and assignment. 1.2 Project Scope 1.2.1 As agreed with Cornwall Council the project will review the following specific aspects of the previous Town Framework Transport Strategy: Review strategic transport model in light of current consultation options for future growth (2,000 proposed residential dwellings of which 1,800 is already permitted); Manually reassign traffic flows to consider the potential impact of the West Carclaze planning application; Review existing transport strategy measures and propose new measures where appropriate; Review any opportunities for bus priority measures; Review developer proposed Edgcumbe Triangle improvement and consider pedestrian accessibility issues; and Assess impact of an estate road running through the Trewhiddle development in relieving Edgcumbe Triangle. 1.3 Report Structure 1.3.1 The report structure will follow the scope of work above. EDG0362 R001 1 December 2013 2 STRATEGIC TRANSPORT MODEL REVIEW Introduction 2.1.1 A review of the St Austell Area Strategic Transport Model has been undertaken to understand any limitations in the model that may impact upon future transport modelling in the area. 2.1.2 The original St Austell SATURN traffic model was developed by Mott MacDonald for Cornwall County Council in 2000/2001 to assess route improvement options on the A391 corridor. The model was then updated by Mott Macdonald in 2004 and by Mouchel in 2007. The Mouchel update did not include additional survey data and therefore the most recent data used in the model was collected in 2003. Since the 2003 data was collected the A30(T) Bodmin to Indian Queens Improvement opened to traffic, visitor numbers at the Eden Project have declined, and St Austell town centre was redeveloped with the opening of White River Place. 2.1.3 As part of the Eco-Communities work Parsons Brinckerhoff updated the model to a base year of 2010 using additional roadside interview survey data, traffic count and journey time data. The model is now WebTAG compliant. Model Calibration and Validation 2.1.4 The Local Model Validation Report (LMVR), published by Parsons Brinckerhoff in September 2011 (reference WHV285300DL) concludes that the model accurately represents the existing traffic situation within the study area. However, it should be noted that calibration of the PM peak model did fall below the DfT threshold of 85% of link flows being within a specified threshold and only achieved 80% of links within the thresholds. Overall calibration is achieved because the AM peak achieved a 97% calibration level. This does raise some potential questions regarding the validity of the PM peak model but discussions with Parsons Brinckerhoff suggest that the principal road network within the study area achieved appropriate calibration levels. Network Structure 2.1.5 Reviewing the network structure within the Town Framework study area confirms that the network is appropriate for determining traffic impact associated with development proposals. EDG0362 R001 2 December 2013 3 WEST CARCLAZE DEVELOPMENT TRAFFIC IMPACT Introduction 3.1.1 Cornwall Council is currently progressing a planning application for the West Carclaze Eco-Communities development, which will comprise approximately 1,500 residential dwellings plus associated community facilities. Cornwall Council is now leading on this project as EcoBos, the Eco-Communities developer has put its plans on hold due to the current financial climate and uncertainty over the emerging Local Plan. 3.1.2 CORMAC Solutions Limited has been commissioned by Cornwall Council’s Planning Service to produce the Transport Assessment and Travel Plan in support of this planning application but this work will not commence until February 2014. Therefore, an estimate of the potential development impact on St Austell has been produced as part of this review. 3.1.3 At this stage the access strategy for the West Carclaze development has not been finalised as Cornwall Council has only recently commissioned the master planning project. Savills have been commissioned to undertake this work but the emerging master plan will not be identified until early 2014. However, it is assumed that the development will access the highway network onto the A391 in the vicinity of Carluddon and the B3274 in the vicinity of Carthew. Figure 3.1 shows the West Carclaze development area and potential access strategy. Trip Generation, Distribution and Assignment 3.1.4 Until the development mix is finalised it is not possible to develop an accurate trip generation for the West Carclaze site. However, assuming a development in the order of 1,500 residential dwellings Table 3.1 summarises potential trip generation. Trip Rate Trip Numbers Time Arr. Dep. 2 Way Arr. Dep. 2 Way 08:00 to 08:59 0.16 0.57 0.73 240 855 1,095 17:00 to 17:59 0.39 0.25 0.64 585 375 960 Table 3.1 Assumed Residential Trip Rates – West Carclaze 3.1.5 Table 3.1 identifies that the West Carclaze development could generate in the order of 1,000 two way trips per hour in the peak hours. Not all of this traffic will travel to St Austell as some will head north to the A30(T) to access other towns in the area. As the detailed trip distribution work has not yet been undertaken for the West Carclaze development assumptions have been made as to where the vehicle trips will travel to/from. These assumptions are summarised in Table 3.2. EDG0362 R001 3 December 2013 Origin / Destination Assumed Percentage Two Way Trips A30(T) East 20% 200 A30(T) West 20% 200 A390 East 10% 100 A390 West 20% 200 St Austell 30% 300 Table 3.2 Assumed Residential Trip Distribution and Assignment 3.1.6 Based on the assumed traffic volumes identified in Table 3.2 it is possible that approximately 400 trips to and from the West Carclaze Development will route northwards onto the A30(T) to access towns such as Newquay, Bodmin, Wadebridge, Launceston and to travel further afield to Devon. 3.1.7 This would result in approximately 600 trips per hour travelling southwards and therefore impacting on the St Austell highway network. 3.1.8 For journeys having origins or destinations along the A390 to the west of St Austell, ie trips to or from Truro or further afield, the routing to the West Carclaze development could be split between the B3274 through Carthew and Ruddlemoor to reach St Austell and then Truro Road to reach the A390 or via the A391, Treverbyn Road, Slades Road and onto the A390 near Mount Charles. 3.1.9 For journeys having origins or destinations along the A390 to the east of St Austell, ie, trips to and from Par, Liskeard, etc, routing south along the A391 would be the quickest route. 3.1.10 For journeys having origins and destinations in St Austell the routing could be the B3274 through Carthew and Ruddlemoor, or Treverbyn Road onto Slades Road or Tregonissey Road. 3.1.11 Figure 3.2 shows potential two-way flow increases on the major roads in St Austell based on the above assumptions. Potential Traffic Impact 3.1.12 Based on the junctions that were previously identified in the Town Framework Transport Strategy the West Carclaze development is likely to increase traffic impact at: A3058 Edgcumbe Road / B3274 Truro Road A390 / B3273 Penwinnick Road / Pentewan Road Treverbyn Road / Tregonnissey Road / Slades Road / Carclaze Road Slades Road / Sandy Hill / Clifden Road / Polkyth Rad 3.1.13 However, with an overall reduction in traffic associated with a lower growth scenario for St Austell impact may be no worse than previously identified.