A2300 FEASIBILITY STUDY & STRATEGIC OUTLINE BUSINESS CASE
Transcript of A2300 FEASIBILITY STUDY & STRATEGIC OUTLINE BUSINESS CASE
A2300 FEASIBILITY STUDY & STRATEGIC OUTLINE BUSINESS CASE Deliverable D11b - Non-technical summary report 18/07/2014
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Project number: 70000985 Prepared for West Sussex County Council Dated: 18/07/2014 2
Quality Management
Issue/revision Issue 1 Revision 1 Revision 2 Revision 3
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Date 18 July 2014
Prepared by WSP-PB
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This report, and information or advice which it contains, has been prepared for the sole benefit, internal use and information of West Sussex County Council for the purposes set out in the report or instructions commissioning it (October 2013) and has been prepared with reasonable skill, care and diligence. This report has been prepared by WSP-PB in their professional capacity as Consultants and in performance of WSP–PB’s duties and liabilities under its contract with West Sussex County Council. Any advice, opinions, or recommendations within this report should be read and relied upon only in the context of the report as a whole. The advice and opinions in this report are based upon the information made available to WSP-PB at the date of this report and on current UK standards, codes, and technology and construction practices as at the date of this report. The contents of the report do not, in any way, purport to include any manner of legal advice or opinion.
The transport modelling that has been carried out under the terms of our appointment (October 2013) and described in this report has been carried out using SATURN (version 10.9.24). Transport modelling software of this type provides predictions of transport flows on the basis of a number of assumptions. The assumptions made in developing the transport model have been identified within this report.
The liability of WSP-PB in respect of the information contained in the report will not extend to any third party. WSP-PB accept no responsibility for any costs or losses howsoever incurred as a result of the use of the output from this report unless it is proved to have failed to exercise the degree of skill and care embodied in the terms and conditions of the governing appointment (October 2013) having regard to the use of the software and the assumptions made.
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A2300 FEASIBILITY STUDY & STRATEGIC OUTLINE BUSINESS CASE Deliverable D11b - Non-technical summary report
18/07/2014
Client West Sussex County Council
First Floor
Northleigh
County Hall
West Street
Chichester
PO19 1RH
Consultants WSP UK Limited
Mountbatten House
Basing View
Basingstoke
Hampshire
RG21 4HJ
Tel: +44 (0)12 5631 8800
Fax: +44 (0)12 5631 8700
www.wspgroup.com
Parsons Brinckerhoff
Westbrook Mills
Borough Road
Godalming
Surrey
GU27 2AZ
Tel: +44 (0)1483 528400
www.pbworld.com
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Table of Contents
1 Introduction ............................................................................ 5
2 Data collection ....................................................................... 6
3 BHTM: Base and forecast traffic modelling ............................ 7
4 Option development............................................................... 8
5 Option refinement & testing ................................................... 9
6 Cost estimates ..................................................................... 14
7 Value for money appraisal ................................................... 15
8 Risk register and delivery programme ................................. 16
9 Conclusions ......................................................................... 17
Appendices Appendix A: Summary of final improvement package for Scenario 1, Scenario 2 and Scenario 3
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1 Introduction 1.1 Background 1.1.1 The Mid Sussex Transport Study (MSTS) published in 2011 by Mid Sussex District Council (MSDC)
sought to evaluate the transport impacts of their District Plan development allocations at 2021 and 2031 with the latter being the horizon year for the full completion of the District Plan development.
1.1.2 There are existing planning permissions for three sites for residential development (1,200 – 1,300 units) at Burgess Hill (land east of Kings Way, land at Fairbridge Way and land at Keymer Brick & Tile Works). Further development has been identified in the submission version of the District Plan, notably the Northern Arc development and the Goddard’s Green development.
1.1.3 The MSTS identified that District Plan proposals would cause network congestion problems resulting in a potential need for improvement to the existing A2300. Traffic flows on the road are currently in the region of 20,000 vehicles per day and the dualling of the existing single carriageway alignment was identified as providing the increased capacity necessary to enable planned local development.
1.1.4 WSP-PB has been commissioned by West Sussex County Council (WSCC) to identify an appropriate improvement scheme for the A2300 and undertake an assessment of the impacts of any improvements.
1.2 Study Area 1.2.1 The study area is shown in figure 1.1.
Figure 1.1: Study area and key junctions
1.3 Objectives 1.3.1 The primary objectives of this study are to:
identify an appropriate improvement scheme for the A2300
provide input to following sections of the Coast to Capital Local Transport Body Major Schemes Prioritisation Methodology process:
provide a scope of further work to be undertaken to produce an ‘Outline Business Case’ (in accordance with ‘The Transport Business Case’, DfT January 2013)
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2 Data collection
2.1 Burgess Hill transport model 2.1.1 A review of the 2010 Burgess Hill Transport Model (BHTM) was undertaken and it was proposed that
a Manual Classified Turning Count (MCTC) was undertaken at the A23/A2300 roundabouts to improve the turning movements and allow for a robust assessment of the junction performance at the western end of the route. The MCTC was undertaken by Nationwide Data Collection (NDC) on the 6 November 2013.
2.2 Accident data 2.2.1 Five year accident data for the A2300 between the A23/A2300 Hickstead Interchange and A273
Jane Murray Way including these junctions at either end was supplied by WSCC.
2.2.2 The review of the five-year accident data for the study area reveals a low accident frequency and where clusters do occur (at junctions) the contributing factors are in most cases not related to the existing highway design.
2.2.3 The exception to this is at the A2300 / Bishopstone Lane junction. The junction forms part of a cycle route between Burgess Hill and Hickstead. Two accidents here involved cyclists while a further two accidents were rear-end shunts to stationary westbound facing vehicles, waiting behind a driver wishing to turn right into Bishopstone Lane.
2.3 Strategic development 2.3.1 To help inform the study, background information associated with the two major developments
(Goddard’s Green and Northern Arc) was collated and reviewed.
Northern Arc
2.3.2 The Northern Arc site is a mixed use development (residential, B1 employment, schools, local centres and community sports centre) located immediately to the north of Burgess Hill.
2.3.3 The Northern Arc site is proposed to include a new road, known as the “Northern Arc Link Road” which would cross the A2300 at a new junction located to the north-west of the A2300 / A273 junction. The link road would link southward to the A273 Jane Murray Way and eastwards to A273 Isaacs Lane, also forming junctions with the B2036.
Goddard’s Green
2.3.4 The Goddard’s Green site is a 15Ha employment site comprising 50,000sq.m of B1b / B1c / B2 / B8 employment units located south and west of the A2300. A Transport Assessment, published in August 2013, outlined improvements to the A2300 / Cuckfield Road junction. Proposals include localised entry widening (extension of flare lanes) to both the eastbound and westbound approaches, along with bus stops either side of the carriageway, on the eastern arm.
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3 BHTM: Base and forecast traffic modelling
3.1 Introduction 3.1.1 The assessment of the A2300 options was undertaken using the BHTM. The BHTM (AM peak) was
built in 2010 by WSP and funded by Gleeson, Wates, Rydon and Sunley to a specification agreed with West Sussex County Council (WSCC).
3.1.2 It should be noted that the base year version of the model used for the assessment of the A2300 improvement options is a refinement of the original base year model (developed by WSP in 2010). The refinement of the model allows a more accurate reflection of flows and delays at the A23/A2300 interchanges using November 2013 turning counts and provides an improved basis for the assessment.
3.2 Base model re-validation 3.2.1 The MCTC undertaken on the 6 November 2013 has been used in a local re-validation exercise of
the BHTM. The re-validated BHTM has been used to produce the 2031 forecast year AM peak model for assessment of the improvement options.
3.3 Do Minimum model development 3.3.1 The assessment of the A2300 improvement options has been undertaken against the Do Minimum
developed for a single year of 2031 and a single time period, which is AM peak (08:00-09:00). The Do Minimum comprises:
Background growth
Committed developments
Northern Arc development
Goddard’s Green development
Additional infrastructure improvements
3.3.2 It is important that the correct quantum and location of development and associated infrastructure is included in the transport model used for the assessment of the A2300 improvement scheme options.
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4 Option development 4.1 Initial stakeholder consultation
4.1.1 Six responses were received from the 19 key stakeholders identified. Of the six responses received, one had no comment to make, four provided detailed comments, and Hurstpierpoint & Sayers Common Parish Council requested that no further work was undertaken at this stage. The Twineham Parish Council response outlined how each of the key junctions in the study area (and some that are not) operate and confirmed conclusions drawn from a site visit and WSCC:
western A23 Interchange roundabout junction approaches capacity during morning peak hours with a dominating west to north A2300 flow which causes queuing on the northbound A23 slip
eastern A23 Interchange roundabout junction does not suffer major delays
delays at the A2300 / Cuckfield Road roundabout are minimal
4.2 Option development
4.2.1 The link improvements considered, initially revolved around the upgrading of the A2300 to a two lane dual carriageway (in both directions). Further analysis was undertaken to determine if dualling of the full length of the A2300 was required or certain sections only. In addition to the Northern Arc access junction on the A2300 the junction improvements considered are listed in table 4.1. Table 4.1: Junction improvement options
Junction Potential scheme
A23 Hickstead Interchange
Grade separated roundabout (merge two existing dumbbell roundabouts) Increase existing roundabout ICD and Increase existing roundabout ICD and signalisation Southbound merge upgrade (type B or E) Northbound diverge upgrade (type C)
A2300 / Bolney Grange
left in left out from side roads with traffic routed through existing roundabouts) Upgrade junction to T Junction with dedicated right turn lanes Upgrade junction to dual carriageway T Junction with dedicated right turn lanes
A2300 / Job’s Lane
Full closure of junction left in left out from side roads with traffic routed through existing roundabouts) Upgrade junction to T Junction with dedicated right turn lanes (Upgrade junction
to dual carriageway T Junction with right turn lanes
A2300 / Cuckfield Road
Increase existing roundabout ICD Increase existing roundabout ICD and signalisation Signalised junction (cross roads) Increase entry lanes (flare to three lanes)
A2300 / A273
Increase existing roundabout ICD Signalised existing roundabout Signalised junction Increase entry lanes (flare to two/three lanes)
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5 Option refinement & testing 5.1.1 The option refinement and packaging process includes the following scenarios:
Do Minimum: Forecast road network with strategic development junction improvements Scenario 1: DM with A2300 junction improvements only
Scenario 2: DM with partial dualling of the A2300 (between the A23 interchange and the Northern Arc junction). The Northern Arc link road south of the A2300 and the A2300 link between the Northern Arc junction and the A272 are both assumed to be single lane 40mph roads
Scenario 3: DM with full length dualling of the A2300 (between the A23 interchange and the A273 Jane Murray Way junction)
5.1.2 The final improvement packages (including the developer proposed Northern Arc junction) are provided in Appendix A. The final improvement scenarios have been refined based on the findings of a Stage 1 Road Safety Audit (RSA).
Scenario 1 - Junction improvements only
5.1.3 For the A23 Interchange West junction a scheme was developed that signalised the A2300 western approach and the A23 northbound off-slip.
5.1.4 For the westbound approach to the A2300 Interchange East junction, the flare length was increased.
5.1.5 A scheme has not been included in the final package of improvements for the eastbound approach to the Cuckfield Road junction due to the marginal over-capacity performance and the limited options for improvement without significant alterations to the junction.
Scenario 2 – Partial dualling
5.1.6 Building on Scenario 1 but incorporating dualling of the A2300 (in both directions) between the A23 Interchange and the developer proposed Northern Arc junction. The junction model results for this scenario showed that the signals scheme for the A23 Interchange West junction and the entry widening on the eastern approach to the A23 Interchange East junction continue to provide sufficient capacity.
Scenario 3 – Full dualling
5.1.7 In Scenario 3 the full length dualling of the A2300 was tested. The results for all the key junctions predicted that they would continue to operate within theoretical capacity.
Summary – Traffic flows, Volume over Capacity and delays
5.1.8 Table 5.1 details a comparison of the passenger car unit (pcu1) flows and shows that Scenario 2 and Scenario 3 have similar increases over the Do Minimum. The main difference is on the Northern Arc link where Scenario 3 shows traffic switching from this route in the Do Minimum onto the A273 and then the A2300 route.
1 passenger car unit (pcu) is frequently used in traffic assessment work and is based on the principal of translating all vehicles into a common traffic currency. It is a vehicle unit used for expressing highway capacity where one car is considered as a single unit and heavy vehicles are considered to be 2.9.
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5.1.9 The northbound off-slip from A23 to the A23 Interchange West junction shows that the predicted actual flow increases from 400pcu in the 2031 Do Minimum scenario to 542 pcu and 546 pcu in the 2031 Scenario 2 and Scenario 3 respectively. This is due to the increased flow attracted to the route by the extra link capacity on the A2300 due to the respective dualling scenarios. Table 5.1: Comparison of pcu flows between scenarios
Road section Do Minimum Scenario 1 Scenario 2 Scenario 3
Northbound off-slip from A23 to the A23 Interchange West junction
northbound 400 462 542 546
Southbound off-slip from A23 to the A23 Interchange East junction
southbound 905 924 1,038 1,050
Between A23/A2300 Junction and the Cuckfield Road roundabout
eastbound 1,305 1,386 1,581 1,596
westbound 1,363 1,341 1,717 1,749
Between the Cuckfield Road roundabout and the Northern Arc roundabout
eastbound 1,299 1,421 1,471 1,552
westbound 1,477 1,464 1,779 1,832
Between the Northern Arc roundabout and the A273/A2300 roundabout
westbound 583 687 551 905
westbound 638 775 670 1096
Between the Northern Arc roundabout and Jane Murray Way south of A2300
northbound 663 529 706 373
southbound 667 685 789 528
Northern approach to the Northern Arc Roundabout
northbound 161 171 216 228
southbound 289 272 488 472
5.1.10 Table 5.2 details a comparison of the Value over Capacity (VoC)2 values between the different scenarios which shows that in Scenario 2 the VoC value on the westbound approach to the A23/A2300 is reduced to 70 which is a reduction of 28 over the Do Minimum.
5.1.11 The westbound approach to Cuckfield Road roundabout reduces from 99 (Do Minimum) to 91 (Scenario 2) which is a greater reduction than shown in Scenario 3 which reduces to 94.
2 The Volume over Capacity (VoC) ratio is an industry standard indicator of how close the junction, link or turn is to the theoretical capacity (i.e. VoC = 100), under the prevailing traffic flows.
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5.1.12 The northbound off-slip from A23 to the A23 Interchange West junction shows a reduction in the VoC value from 95 in the 2031 Do Minimum to 59 in Scenario 1. This arm has a similar VoC value on Scenario 2 (VoC is 94) and Scenario 3 (VoC is 95) although table 5.1 shows that the predicted actual flow increases from 400 pcu in the 2031 Do Minimum scenario to 542 pcu and 546 pcu in the 2031 Scenario 2 and Scenario 3 respectively. This is due to the increased flow attracted to the route by the extra link capacity on the A2300 due to the dualling of the sections of the route.
5.1.13 Due to the switch of traffic away from the Northern Arc link onto the A273 and then the A2300 the westbound approach to the Northern Arc roundabout shows an increase from 54 in the Do Minimum scenario to 89 in Scenario 3. Table 5.2: Comparison of VoC values between scenarios
Road section Do Minimum Scenario 1 Scenario 2 Scenario 3
Northbound off-slip from A23 to the A23 Interchange West junction 95 59 94 95
Southbound off-slip from A23 to the A23 Interchange East junction 53 56 66 67
Westbound approach to the A23/A2300 junction 98 78 70 71
Eastbound approach to the Cuckfield Road roundabout 88 96 73 77
Westbound approach to the Cuckfield Road roundabout 99 100 91 94
Northbound approach to the Cuckfield Road roundabout 78 77 87 87
Eastbound approach to the Northern Arc roundabout 75 71 72 77
Westbound approach to the Northern Arc roundabout 54 61 74 89
Northbound approach to the Northern Arc roundabout 71 62 91 77
5.1.14 Table 5.3 details a comparison of the average delay per pcu values between the different scenarios which shows that Scenario 2 and Scenario 3 reduces the average delay on the westbound approach to the A23/A2300 to four seconds from 19 seconds.
5.1.15 The northbound off-slip from A23 to the A23 Interchange West junction shows an increase in the average delay per pcu from 40 seconds in the 2031 Do Minimum to 62 seconds in Scenario 2 and 65 seconds in Scenario 3. This is due to the increased flow attracted to the route by the extra link capacity on the A2300 due to the dualling of the sections of the route.
5.1.16 The eastbound approach to Cuckfield Road roundabout reduces to five seconds in Scenario 2 and Scenario 3 from 31 seconds in the 2031 Do Minimum scenario. In the westbound direction delays are reduced to seven seconds in Scenario 2 and eight seconds in Scenario 3 from 41 seconds in the 2031 Do Minimum scenario.
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Table 5.3: Comparison of average delay (seconds) per pcu values between scenarios
Road section Do Minimum Scenario 1 Scenario 2 Scenario 3
Northbound off-slip from A23 to the A23 Interchange West junction 40 22 62 65
Southbound off-slip from A23 to the A23 Interchange East junction 6 6 7 7
Westbound approach to the A23/A2300 junction 19 18 4 4
Eastbound approach to the Cuckfield Road roundabout 31 38 5 5
Westbound approach to the Cuckfield Road roundabout 41 40 7 8
Northbound approach to the Cuckfield Road roundabout 18 16 27 31
Eastbound approach to the Northern Arc roundabout 22 4 4 4
Westbound approach to the Northern Arc roundabout 8 6 21 11
Northbound approach to the Northern Arc roundabout 14 12 25 22
Summary – journey times
5.1.17 Travel times provide an easy to understand representation of network performance. Journey time information has been extracted from the BHTM for the 2010 base year, 2031 Do Minimum, 2031 Scenario 1, 2031 Scenario 2 and 2031 Scenario 3 for the following routes:
Westbound: from the A273/A2300 junction to the northbound on-slip to the A23
Eastbound: from the northbound off-slip from the A23 to the A273/A2300 junction
5.1.18 It must be stressed that the predicted corridor journey times extracted from the SATURN assignment model include the average delay over the modelled hour period. There may be times during that hour period where there are greater or lesser delays at individual junctions on each route. Table 5.4 shows the comparison between the scenarios. Figure 5.1 and figure 5.2 show these results in graphical format. Table 5.4: Comparison of journey times between scenarios in minutes
Road section Base year Do Minimum Scenario 1 Scenario 2 Scenario 3
Westbound 4.2 5.0 5.0 4.2 3.9
Eastbound 4.8 4.7 4.3 4.3 3.9
5.1.19 The full dualling scenario (Scenario 3) shows the greatest reduction in journey time in both the westbound and eastbound direction when compared to the Do Minimum. Scenario 3 is approximately 66 seconds (westbound) and 48 seconds (eastbound) quicker when compared to the Do Minimum. Scenario 3 is predicted to be approximately 18 seconds (westbound) and 24 seconds (eastbound) quicker than Scenario 2.
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Figure 5.1: A23/A2300 corridor journey time - westbound
Figure 5.2: A23/A2300 corridor journey time - eastbound
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6 Cost estimates 6.1.1 Cost estimates have been prepared using approximate quantities with rates derived from either the
SPON’s Civil Engineering and Highway Works Price Book3 with appropriate enhancement for overhead and profit or from analogous historic rates which have been indexed forward to current rates. The base date for the estimates is Q1 2014 and no allowance has been included for:
Land and compensation costs
VAT
Inflation
Design and supervision
Work to existing services (no detail available)
Widening existing over-bridge
6.1.2 A sum has been included in respect of optimism bias/ risk; this has been calculated at 45% of the total cost and is based on advice contained in the Highways Agency Annex 1 estimate forms for schemes at this stage of development.
6.1.3 Summary cost estimates are shown in table 6.1.
Table 6.1: Cost estimates
Scenario 1 Scenario 2 Scenario 3
Main Line Dualling £10,060,841 £10,200,333
A23 Junction signalisation (West Rbt) £432,057 £500,282 £500,282
Junction works (East Rbt) £68,225
Cuckfield Road roundabout £51,249 £51,249
Minor junction works and blocking up £100,000
Full length footway/cycleway £432,750 £438,750
Minor junction works and blocking up £100,00 £100,00
Widen bridge to three lanes
External walkways to bridge
Sub-Total £600,282 £11,145,122 £11,290,614
Preliminaries (7.5%) £45,021 £835,884 £846,796
Traffic Management (20%) £120,056 £2,229,024 £2,258,123
Sub-Total £765,360 £14,210,031 £14,395,533
Contingency / Risk (45%) £344,412 £6,394,514 £6,477,990
Total £1,109,771 £20,604,544 £20,873,523
3 The SPON’s Civil Engineering and Highway Works Price Book gives costs for both general and civil engineering works and highway works, and provides a full breakdown of labour, plant and material elements.
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7 Value for money appraisal 7.1.1 The value for money appraisal has been undertaken using Transport User Benefits Appraisal
(TUBA)4 and COst and Benefit to Accidents – Light Touch (COBALT)5 for the scenarios described in paragraph 5.1.1. The results for TUBA are shown in table 7.1 and COBALT in table 7.2.
Table 7.1: TUBA economic assessment summary table (£000s)
Scenario 1 Scenario 2 Scenario 3
Benefits
Consumer Users (Commuting 424 2,433 2,836
Consumer Users (Other) 401 2,359 2,760
Business Users and Providers 665 6,760 7,716
Indirect Tax Revenues -15 586 704
Greenhouse Gases 4 -231 -277
Present Value of Benefits (PVB) 1.479 11.907 13.739
Table 7.2: COBALT economic assessment summary table (£000s)
Type of casualty Scenario 1 Scenario 2 Scenario 3
Benefits
Total accidents saved by scheme 56 149 119
Total casualties saved by scheme:
Fatal 1 6 6
Serious 8 33 28
Slight 73 178 137
Economic benefits 3.714 14.947 12.599
7.2 Summary 7.2.1 The total Present value of Benefits (PVB) and Present Value of Costs (PVC) are summarised in table
7.3. The PVC is different to the cost estimate in table 6.1 due to discounting. Table 6.1 shows the estimated scheme cost in 2014 prices with table 7.3 showing scheme costs in 2010 prices.
Table 7.3: Summary of Present Value of Benefits (£000s)
Scenario 1 Scenario 2 Scenario 3
Present Value of Benefits (PVB) 5.193 26.854 26.338
Present Value of Costs (PVC) 0.854 15.861 16.068
Benefit to Cost Ratio (BCR) 6.081 1.693 1.639
7.2.2 Based on the economic assessment Scenario 1 shows the greatest value for money. Scenario 2 and Scenario 3 have similar benefits due to the improved travel time benefits for commuters and other users and, in particular, for business users. Scenario 2 shows a greater BCR value of 1.693 than Scenario 3 which shows a BCR value of 1.639.
4 Transport User Benefit Appraisal (TUBA) computer program is used to carry out transport scheme economic appraisal in accordance with the Department for Transport (DfT) published guidance in Units A.1 of the https://www.gov.uk/transport-analysis-guidance-webtag. 5 The COBALT (COst and Benefit to Accidents – Light Touch) computer program has been developed by the Department for Transport (DfT) to undertake the analysis of the impact on accidents as part of economic appraisal for a road scheme.
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8 Risk register and delivery programme 8.1.1 The delivery programme has been completed in outline detail for the junction improvements
(Scenario 1), partial dualling (Scenario 2) and full dualling (Scenario 3).
8.1.2 It is estimated that given an initial application for funding on the 14 May 2014 the following timelines would be possible:
Junction improvement (Scenario 1): begin construction in December 2015 with completion in September 2016
Partial dualling (Scenario 2): begin construction in September 2016 with completion in January 2018
Full dualling (Scenario 3): begin construction in December 2016 with completion in May 2018
8.1.3 The dates included paragraph 8.1.2 includes for analysis of traffic impacts, detailed design, topographical and geotechnical surveys, Compulsory Purchase Orders (CPO), Side Roads Orders (SRO), Traffic Regulation Orders (TRO), consultation and construction period.
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9 Conclusions 9.1.1 WSP-PB has been commissioned by WSCC to identify an appropriate improvement scheme and
assessment of the impacts for the A2300. An option refinement process was undertaken for:
Scenario 1: Existing road network with junction improvements only
Scenario 2: Partial dualling of the A2300 (between the A23 interchange and the Northern Arc junction). The Northern Arc link road south of the A2300 and the A2300 link between the Northern Arc junction and the A272 are assumed to be a single lane 40mph road
Scenario 3: Full length dualling of the A2300 (between the A23 interchange and the A273 Jane Murray Way junction)
9.1.2 A comparison of the different scenarios in terms of the changes in traffic flows, VoC ratios and the average delay to vehicles on the road network show that Scenario 2:
Attracts additional traffic from e.g. B2036 Harvest Hill/A272 Bolney Road route and serves as a more attractive route for traffic to and from Burgess Hill from the A23
Reduces those VoC ratios that are greater than 85 on the westbound approach to the A23/A2300 junction and the eastbound approach to the Cuckfield Road roundabout to below 75.
VoC on the eastbound approach to Cuckfield Road roundabout from 99 in the Do Minimum to 91
Reduces the average delay per vehicle on the westbound approach to the A23/A2300 junction and the eastbound and westbound approaches to the Cuckfield Road roundabout to below 10 seconds from 19 to 41 seconds in the Do Minimum
Northern Arc link acts as a more strategic route by keeping traffic off the existing A273 allowing the A2300 approach to the A273/A2300 junction to have more of an urban feel on the approach to Burgess Hill
Journey times reductions between the A273/A2300 junction and the A23/A2300 junction of 0.8 minutes westbound and 0.4 minutes eastbound compared to the Do Minimum scenario
9.1.3 Based on the economic assessment the junction improvement option (Scenario 1) shows the greatest value for money however the traffic assessment shows that it does not give the same level of reductions in VoC, average delays and journey times as the other scenarios.
9.1.4 The partial dualling scenario (Scenario 2) and full dualling scenario (Scenario 3) have similar benefits which is due to the improved travel time benefits for commuters and other users and, in particular, for business users. The partial dualling scenario (Scenario 2) shows a greater BCR value of 1.693 than the full dualling scenario (Scenario 3) which shows a BCR value of 1.639.
9.1.5 It must be stressed that the benefits produced in this assessment represent an under-estimate of the total benefits produced from the scheme for the following reasons:
AM peak model only
No benefits were calculated for the PM peak period (16:00-19:00)
No benefits were calculated for the inter peak period (10:00-16:00)
No benefits were calculated for weekday off-peak periods (19:00–07:00)
No benefits have been calculated for weekends or bank holidays
9.1.6 There would likely be a similar level of benefits in the PM peak with relatively few benefits in the inter peak due to a lack of congestion which would mean less travel time savings. Overall the comparison of all elements of the assessment (deliverability, scheme costs, traffic flows, Volume over Capacity, average delays, journey times, TUBA and COBA assessment) leads to the conclusion that the partial dualling scenario (Scenario 2) is the most appropriate improvement scheme for the A2300 corridor.
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Project number: 70000985 Dated: 18/07/2014 Revised:
Appendices
Appendix A Summary of final improvement package for Scenario 1, Scenario 2 and Scenario 3
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Project number: 70000985 Dated: 18/07/2014 Revised:
Figure A.1: Scenario 1 improvement package
Figure A.2: Scenario 2 improvement package
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Project number: 70000985 Dated: 18/07/2014 Revised:
Figure A.3: Scenario 3 improvement package
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