Highways Technical Note
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HIGHWAYS TECHNICAL NOTE Author: Paul Mew Associates Date: May 2020 Project: P2300: Dunsfold Oil Well, High Loxley Road Subject: Highways Review of UKOG Planning Application to SCC 1.0 INTRODUCTION 1.1 Paul Mew Associates (PMA) is instructed to carry out a review of highways aspects relating to a planning application made by UK Oil and Gas Investments PLC (UKOG) for proposed exploratory mineral extraction on land south of Dunsfold Road and east of High Loxley Road, Dunsfold, Surrey. 1.2 The proposal, submitted to Surrey County Council (SCC) under planning reference 2019/0072 and validated in April 2019, comprises the following: “The construction, operation and decommissioning of a well site for the exploration and appraisal of hydrocarbon minerals from one exploratory borehole (Loxley-1) and one side - track borehole (Loxley - 1z) for a temporary period of three years involving the siting of plant and equipment, the construction of a new access track, a new highway junction with High Loxley Road, highway improvements at the junction of High Loxley Road and Dunsfold Road and the erection of a boundary fence and entrance gates with restoration to agriculture.” 1.3 The local planning authority is Waverley Borough Council (WBC) whereas the local highway authority is SCC. The minerals planning authority is also SCC, therefore SCC will determine the planning application. 1.4 From a highways point of view the primary concerns relate to the impact of the proposal on traffic flow on the local and wider highway network, and the impact of the necessary Unit 1, Plym House, 21 Enterprise Way, London, SW18 1FZ Tel: 020 8780 0426 E-mail: [email protected] Website: www.pma-traffic.co.uk enabling works to accommodate the heavy commercial vehicles (HCV) on common land. This report assesses both issues as far as is practicable based on the information that has been submitted with the planning application. Principally these documents are: • Transport Statement (TS) Loxley (April 2019) Parts 1 and 2; • Loxley Well Site Supplementary Transport Statement (August 2019); • Drawing ZG-UKOG-L1-PA-13 Proposed Access Layout Plan – High Loxley Road; • Drawing ZG-UKOG-L1-PA-14 Proposed Access Layout Plan – Pratts Corner. 1.5 At the time of preparing this report the planning application is currently under consideration by SCC. 1.6 We are aware of a planning application for an alternative access to the site directly from Dunsfold Road which was submitted to SCC under planning reference 2019/0108 and was validated in July 2019. This application was withdrawn in March 2020. 1.7 We have briefly reviewed the latter planning application. It has been noticed that the vehicle to vehicle stopping sight distances (SSDs) contained in the supporting Transport Statement submitted with the planning application (drawing number LTP/3134/04/01/01/0) have been incorrectly plotted looking to the left, and achieving the required visibility splays may require more of the highway verge (which might be common land) to be cleared of trees and foliage. Notwithstanding, as the planning application has since been withdrawn no further analysis of this scheme has been carried out. 1.8 The following chapter provides an overview of the current planning application (2019/0072) regarding the impact of the proposal on traffic flow on the local and wider highway network. Chapter 3 assesses the impact of the necessary enabling works to accommodate the HCVs on common land. Page 2 of 12 2.0 IMPACT ON TRAFFIC FLOW 2.1 The site is located to the east of High Loxley Road, a single lane unclassified road that is subject to the national speed limit of 60 mph. The width of the carriageway along High Loxley Road is approximately 3.0m which is wide enough for single file traffic flow. The road is flanked on both sides by trees and hedgerows that form the boundary with adjacent agricultural land and common land. 2.2 High Loxley Road joins the classified road network at Dunsfold Road (B2130) via a priority junction with High Loxley Road. This, together with the adjacent Dunsfold Common Road junction with Dunsfold Road, is known locally as ‘Pratts Corner’. Dunsfold Road is a two-way single carriageway and is also subject to the national speed limit of 60 mph. The width of the carriageway along Dunsfold Road is approximately 6.0m. 2.3 The TS submitted with the planning application states that all traffic associated with the proposed development will enter High Loxley Road via a left turn movement from B2130 Dunsfold Road and exit High Loxley Road via a right turn movement to B2130 Dunsfold Road. All traffic would therefore avoid The Green, Dunsfold, Loxhill, Hascombe, Busbridge, and Godalming (accessed via Dunsfold Road). Summary of Proposed Highways Works 2.4 Appendix 2 of the TS submitted with the planning application provides details of the proposed highway works within High Loxley Road consisting of: • The formation of a priority junction between High Loxley Road and the proposed access route into the site; • Localised widening on the west side of High Loxley Road north of the proposed access to facilitate the swept paths of HCVs and Abnormal Indivisible Load Vehicles (AILVs) entering and exiting the site; • Localised widening on the east side of High Loxley Road south of the proposed access to provide a passing place for vehicles travelling to properties south of the proposed highway access when vehicles travelling north on High Loxley Road are waiting at the proposed portable traffic signals; and Page 3 of 12 • Removal/reduction of a limited section of the existing hedgerow on the east side of High Loxley Road to allow both the construction of the proposed site access and to accommodate required visibility sightlines. 2.5 Appendix 3, 4, and 6 of the TS provides details of the proposed temporary 30 mph speed limit on the wider highway network, the proposed highway improvements at the High Loxley Road junction with Dunsfold Road, and the proposed portable traffic signals at the High Loxley Road and the Dunsfold Common Road junctions with Dunsfold Road respectively: • The introduction of Portable Traffic Signal control equipment to separately control Dunsfold Road (East), Dunsfold Road (West), Dunsfold Common Road, High Loxley Road south of the proposed site access and the proposed site access; • The use of Temporary Traffic Management to facilitate the operation of the temporary traffic signals pursuant to in 'An Introduction to the use of Portable Traffic Signals' (DfT, 2008) and 'Traffic Signs Manual' (DfT, 2009); • The introduction of high friction anti-skid resistance surfacing on the approach to the temporary traffic signals on Dunsfold Road (East), Dunsfold Road (West) and Dunsfold Common Road pursuant to DMRB: CD236: ‘Surface course materials for construction’; and • A temporary 30 mph speed limit for the duration of the development on High Loxley Road, Dunsfold Road and Dunsfold Common Road on the approach to the ‘Pratts Corner’ junction. Impact on Traffic Flow 2.6 The main impact of the proposal on traffic flow adjoining the site is the planned temporary traffic signals at the Dunsfold Road (East), Dunsfold Road (West), Dunsfold Common Road, High Loxley Road junctions. 2.7 Appendix 8 of the submitted TS presents the results of a weekday AM and PM peak period (07:30-08:30 and 16:30-17:30 respectively) microsimulation ‘Linsig’ model of the planned ‘temporary’ traffic signals. It is noted that the proposal is for a three-year period, however presumably based on the outcome of the exploratory works the precedent would then be established for the traffic signals to be installed on a longer-term basis. Page 4 of 12 2.8 The primary concerns with the output of the traffic simulation model are that the planned signalisation of the junctions will result in a significant delay in the flow of traffic locally which does not currently exist. The significant delays that will be experienced by the current highway users will be as a result of a comparatively minimal number of vehicle trips that will be generated by the proposal. 2.9 The fundamental reason for the significant delay in the flow of traffic locally is the extremely inefficient layout of the junction. Owing to the large number of conflicting movements through the junction only one arm will have green time at any one time. The delay arises from the fact the signals are four-way and sequential. The proposed staging diagram for the portable signal system has been extracted from Appendix 6 of the Transport Statement submitted with the planning application: 2.10 Also, the distance between the stop line at each arm to a point clear of the junction is substantial which means that the inter-green period between each stage needs to be long enough to allow vehicles to safely pass through the junction. The total maximum cycle time for all stages of the signal system is 220 seconds. 2.11 This latter point is compounded by the fact that the planned stop line and signal head for High Loxley Road and the Loxley Site Access is set-back some 175 metres from the B2130 Dunsfold Road. The set-back is necessary owing to the narrow width of High Loxley Road making it capable of accommodating one-way traffic flow only. 2.12 The results of the Linsig model in respect to the ‘mean max queue PCU’ (passenger car unit) and the ‘average delay per PCU’ (seconds per PCU) is set out in the following tables as noted from Appendix 8 of the submitted TS. Figures 1 and 2 of this report provide a broad illustration of the queuing and where the delays will be experienced: Page 5 of 12 AM PEAK 07:30-08:30 Junction Arm Average Time Delay Mean Max.