A483 Wrexham Local Model Validation Report March 2020 NMWTRA Mott MacDonald 2 Callaghan Square Cardiff CF10 5BT United Kingdom T +44 (0)29 2046 7800 mottmac.com NMWTRA A483 Wrexham 402166 0017 A P:\Cardiff\ERA\ITD\Projects\402495 A483 Wrexham KS2\6.0 Local ModelReports\LMVR\402495_A483 Validation WrexhamLMVR_v1.7 Report accepting changes.docx Mott MacDonald March 2020 Mott MacDonald Limited. Registered in England and Wales no. 1243967. Registered office: Mott MacDonald House, 8-10 Sydenham Road, Croydon CR0 2EE, NMWTRA United Kingdom Mott MacDonald | A483 Wrexham Local Model Validation Report Issue and Revision Record Revision Date Originator Checker Approver Description A November W Davies/N Johnson/ S Arthur/C N/A DRAFT 2019 A Shaw Currie B January W Davies / A Shaw S Arthur C Currie FINAL 2020 C March 2020 W Davies / A Shaw S Arthur C Currie FINAL Document reference: 402166 | 0017_C Information class: Standard This document is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose. We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties. 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N o re pre sent ation , wa rran ty o r un dert aking , exp ress or i mplie d, is made an d no res ponsi bility or liability is acce pted by us to any p arty oth er t han the Cli ent or a ny Reci pient (s), as t o the accu racy or c om plete ness of th e info rm ation cont aine d in t his Rep ort. Fo r t he av oida nce o f do ubt t his Re port do es no t in any way pu rpo rt to includ e a ny leg al, ins ura nce or fin ancial advic e or opini on. 402166 | 0017 | A | March 2020 P:\Cardiff\ERA\ITD\Projects\402495 A483 Wrexham KS2\6.0 Reports\LMVR\402495_A483 WrexhamLMVR_v1.7 accepting changes.docx Mott MacDonald | A483 Wrexham Local Model Validation Report Contents Executive summary 1 Background 1 Base Model Construction 1 Base Model Calibration and Validation 1 1 Introduction 2 1.1 Project Background 2 1.2 Strategic Objectives 2 1.3 Purpose of the Local Model Validation Report 3 1.4 Layout of Report 3 2 Model Description and Data Requirements 4 2.1 Transport Model and Data Requirements 4 2.2 Existing Models and Data 4 2.3 Development of the A483 Wrexham Traffic Model – Overview 4 2.4 Geographical Model Coverage 5 3 Data Collection Summary 6 3.1 Data Used in Model Development 6 3.2 Traffic Count Data 6 3.3 Roadside Interview Surveys 12 3.4 Mobile Phone Data 13 3.5 Journey Time Data 16 4 Model Development – Network 18 4.1 Summary of Approach 18 4.2 Geographical Extent of Model and Network Hierarchy 18 4.3 Highway Link Coding 19 4.4 Simulation Area Junction Coding 20 4.5 Priority Junctions 21 4.6 Roundabouts 22 4.7 Signal Junctions 26 4.8 Merges and Diverges 28 4.9 Assignment User Classes 28 5 Model Development – Matrices 31 5.1 Overview 31 5.2 Zone Structure 31 5.3 Prior Matrix Construction 33 402166 | 0017 | A | March 2020 P:\Cardiff\ERA\ITD\Projects\402495 A483 Wrexham KS2\6.0 Reports\LMVR\402495_A483 WrexhamLMVR_v1.7 accepting changes.docx Mott MacDonald | A483 Wrexham Local Model Validation Report 5.4 Roadside Interview Survey Matrix Build 34 5.5 Mobile Phone Data Matrix Build 36 5.6 Synthetic Matrix Build 38 5.7 Merged Matrix Build – Prior Matrix 40 5.8 Matrix Estimation 42 6 Model Development – Assignment 44 6.1 Overview 44 6.2 Highway Assessment Algorithm and Generalised Cost Parameters 44 6.3 Assignment Model Convergence 45 7 Model Calibration 48 7.1 Summary of Approach 48 7.2 Network 48 7.3 Matrix Estimation 48 7.4 Matrix Zonal Cell Values and Trip Ends 49 7.5 Trip Length Distribution 51 7.6 Analysis of Sector to Sector Movements 52 7.7 Conclusions 55 8 Validation – Network 56 8.1 Analysis of Paths 56 9 Validation – Assignment 64 9.1 Validation 64 9.2 Journey Time Validation 79 10 Conclusions 94 10.1 Base Model Construction 94 10.2 Network Construction 94 10.3 Matrix Construction 94 10.4 Base Model Calibration and Validation 94 Appendices 95 A. Speed Flow Curves – Network Coding Manual 96 B. Link Flow Validation Results 99 402166 | 0017 | A | March 2020 P:\Cardiff\ERA\ITD\Projects\402495 A483 Wrexham KS2\6.0 Reports\LMVR\402495_A483 WrexhamLMVR_v1.7 accepting changes.docx Mott MacDonald | A483 Wrexham 1 Local Model Validation Report Executive summary Background Mott MacDonald has been appointed by the North and Mid Wales Trunk Road Agent (NMWTRA) to construct a strategic model for the A483 at and to the south of Wrexham. The model will be utilised as a tool in assessing possible transport infrastructure options for the A483 at Wrexham and to contribute to the economic appraisal. The purpose of the Local Model Validation Report (LMVR) is to illustrate the development of the 2018 base model of the local highway for the A483 at Wrexham. Base Model Construction The A483 Wrexham Model has been developed with the use of June 2018 traffic data as the base year. The model covers three time periods for an average weekday: ● AM Peak Hour (08:00-09:00); ● Inter Peak Average Hour (10:00-16:00); and ● PM Peak Hour (17:00-18:00). OS digital mapping and Google Maps have both been utilised, as well as additional site visit observations, to construct the network. Origin destination trip information, which serves as the input to the trip matrix construction was derived from three principal sources of data: ● Roadside Interview Survey Data, ● Mobile Phone Data; and ● Census and Land Use Data – for constructing the Synthetic Gravity Model Traffic count data which was commissioned for the model time periods was utilised in multiple ways. This included the production of factors for both for expansion and time period adjustments for the construction of the trip matrices. Base Model Calibration and Validation Both the traffic data and journey time data for the modelled time periods was separately and independently used in the calibration and validation of the traffic model. The base year for the A483 Wrexham strategic model was validated in accordance with the appropriate WebTAG guidance (WebTAG – Unit M3.1). 402166 | 0017 | C |March 2020 Mott MacDonald | A483 Wrexham 2 Local Model Validation Report 1 Introduction 1.1 Project Background 1.1.1 The North and Mid Wales Trunk Road Agent (NMWTRA) has appointed Mott MacDonald Ltd to develop transport modelling tools for use in the assessment of infrastructure improvements on the A483 at Wrexham as part of the Key Stage 2 (KS2) of the Welsh Government’s linear Key Stage Approval process. 1.1.2 Wrexham is one of the key towns in Wales located in the north east corner of the country and serves as a key driver of economic, social and cultural activity. Wrexham’s main connection to the national road network is the A483. The A483 is part of the Strategic Route Network (SRN) running from Swansea to Chester through the heart of Wales. 1.1.3 In the vicinity of Wrexham, the A483 runs just to the west of the town, generally in a north/south direction. For the majority of its length the A483 is a single carriageway road. The section between the A5 at Ruabon (Junction 1) and Junction 38 of the A55 to the south of Chester is an all-purpose dual carriageway containing seven junctions, all of which are grade separated and Junctions 3 to 6 provide access to Wrexham. 1.1.4 The A483 Wrexham Bypass was constructed in the late 1980s and is perceived to experience congestion and delay at times. 1.1.5 The Welsh Government are seeking to maintain the operational capacity and robustness of the A483 and its junctions at Wrexham, while maximising the economic development potential of Wrexham. 1.1.6 As part of KS2, a Stage 2 WelTAG appraisal and technical assessment of options will be undertaken with a view to identifying a preferred solution.