M4 Junction 18A Link Study – Combined Modelled and Appraisal Report

M4 Junction 18a Link Study – Combined Modelled and Appraisal Report

Prepared for South Gloucestershire Council and Highways England

March 2018 Draft

1 The Square Temple Quay Bristol BS1 6DG Draft

Document history

M4 Junction 18a Link Study Combined Modelling and Appraisal Report

This document has been issued and amended as follows:

Version Date Description Created by Verified by Approved by 001 01.03.18 Working Draft JB HS HS

Draft

Contents

Section Page Introduction ...... 1‐1 1.1 Purpose of this Report ...... 1‐1 1.2 Scheme Objectives ...... 1‐1 1.3 Scheme Description ...... 1‐1 1.4 Previous Studies ...... 1‐3 Local Transport Situation ...... 2‐3 2.1 Existing Local Transport System ...... 2‐3 2.2 Key Travel Demands ...... 2‐5 2.3 Transport Problems and Factors ...... 2‐7 2.4 Transport modelling ...... 2‐7 Summary ...... 3‐1 3.1 ComMA Summary Tables ...... 3‐1 3.2 Recommendation...... 3‐8 3.3 Assumptions and Caveats ...... 3‐10 Appendix Appendix A Transport Modelling Report

Draft

SECTION 1

Introduction 1.1 Purpose of this Report This ComMA has been prepared to provide an overview of the modelling and appraisal work undertaken for the M4 Junction 18a Link Study. 1.2 Scheme Objectives The objectives of the M4 Junction 18a Link scheme were agreed as part of Phase 1 of the study and are as follows:  Relieve congestion to M4 J19 and M32 J1, and on the A4174 corridor;  Improve safety by reducing congestion related collisions on M4 J19 and M32 J1, and on the A4174 corridor;  Unlock the economic potential in the north east Bristol Fringe, particularly within Science, Technology and Innovation sectors;  Improve network resilience and journey time reliability;  Minimise the impact of traffic/infrastructure to the natural environment and, where possible deliver opportunities for environmental enhancement; and  Protect and enhance access for non‐car modes. 1.3 Scheme Description The scheme is a link between the A4174 Ring Road on the eastern edge of Bristol and the M4 motorway, between J19 (with the M32) and J18 (with the A46). Figure 1‐1 shows the scheme study area and expected impact while Figure 1‐2 shows a plan of the assessed options. Draft

1‐1

SECTION 1 – INTRODUCTION

Figure 1‐1: Study Area

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Figure 1‐2: Assessed Scheme Options

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SECTION 2 – LOCAL TRANSPORT SITUATION All options also considered required improvements to the junctions of the A4174 south of the link connection as far as the A4. 1.4 Previous Studies The current scheme has basis in the West of England Joint Transport Study (JTS). As part of that work, high level analysis was undertaken by Atkins utilising the highways element of the GBATS4M model with no accounting of differing variable demand impacts between the options or the reference case. The study found a present value of benefits (PVB) of between £670m and £290m with higher values the further west the junction was located.

2Local Transport Situation 2.1 Existing Local Transport System Figure 2‐1 shows the transport context in the local area while Figure 2‐2 shows the major development areas with the planned and under construction public transport interventions. To the east there is M4 J18 with the A46 to Bath while to the north and west the M4 joins with the M5 at the busy Almondsbury interchange and then heads to wales via the Severn Crossings. The M5 runs north, ultimately to Birmingham and south towards Weston‐super‐Mare, Taunton and Exeter.

Draft

Figure 2.1: Transport Context Map

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SECTION 2 – LOCAL TRANSPORT SITUATION

Figure 2‐2: Map showing major development areas together with the proposed transport interventions (Source: West of England Strategic Economic Plan 2015‐2030) Table 2.1 shows a list of existing bus routes in the area, in addition, strategically there are a number of National Express and Megabus intercity coach services that run from the Centre of Bristol to other cities. Draft

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SECTION 2 – LOCAL TRANSPORT SITUATION

Service Route Mon‐Fri frequency

18 Emersons Green – Downend – Frenchay Hospital – UWE Frenchay Campus – Bristol Every 30 mins Parkway – Southmead Hospital – Shirehampton ‐ Lawrence Weston ‐ Henbury

18A Lyde Green – Downend ‐ UWE Frenchay Campus – Bristol Parkway – Southmead Every 60 mins Hospital ‐ Avonmouth

47 / X47 Chipping Sodbury – Yate – Coalpit Heath – Downend – Fishponds – Bristol City Centre Every 30 mins

48 Emersons Green – Downend – Fishponds – Eastville – Bristol City Centre Every 20 mins

49 Emersons Green – Staple Hill – Fishponds ‐ Eastville – Bristol City Centre Every 20 mins

86 Yate – Coalpit Heath – RAM Hill – Lyde Green – Kingswood – Longwell Green Aspects Every 2 hours

462 Lyde Green – Mangotsfield – Bromley Heath – Bristol City Centre – Tyndall Park 4‐6 journeys

620 Old Sodbury – Chipping Sodbury – Yate – Westerleigh – Pucklechurch – Wick ‐ Bath 4‐6 journeys

X48 Bristol & Bath Science Park – Lyde Green – Emersons Green – Downend – Bromley Every 30 mins Heath – Bristol City Centre

X49 Yate – Westerleigh – Pucklechurch – Staple Hill – Fishponds – Bristol City Centre Every hour Table 2.1: Existing bus routes in north Bristol (correct as of July 2017) 2.2 Key Travel Demands The West of England city region has a population of over 1 million. The Core Strategy for South Gloucestershire states that since 1991 traffic on the roads of South Gloucestershire has increased by 30% (compared to the national average of 21%), but within the north fringe of Bristol traffic has increased by 50%. Table 2‐1 shows data derived from the 2011 census, gives an indication of how people in South Gloucestershire travel to work. It shows that the car is by far the dominant mode with just 6 per cent of all journeys to work being undertaken by public transport. High car dependency in South Gloucestershire and the north fringe of Bristol is associated with a lack of alternatives available in the area. As outlined in section 2.3, a number of public transport measures are being implemented in the area, including MetroBus routes to central and south Bristol.

Mode Mode share DraftWest of England South Gloucestershire Bristol north fringe (BS16) Works mainly at or from home 5% 5% 4%

Train 2% 1% 1%

Bus, minibus or coach 7% 5% 8%

Motorcycle 1% 1% 1%

Driving a car or van 59% 70% 65%

Passenger in a car or van 5% 5% 5%

Bicycle 5% 4% 6%

On foot 14% 8% 9% Table 2‐2: 2011 census method of travel to work (excluding those not in employment and other modes of travel)

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SECTION 2 – LOCAL TRANSPORT SITUATION A higher proportion of residents in South Gloucestershire commute over 5km to work then in the West of England or South West as a whole. Only 35% of South Gloucestershire residents travel less then 5km to work.

Distance Travelled Area

South West of England South West Gloucestershire

Less than 5km 35% 44% 41%

Over 5km 55% 45% 45%

Works mainly at or from home 10% 11% 14% Table 2‐3: 2011 census distance travelled to work (all usual residents aged 16 and over in employment the week before the census)

The figure below is taken from a North Bristol SusCom report1, and outlines home postcode locations of members (members include a number of north fringe employers including Airbus, BAE Systems, Bristol & Bath Science Park, MOD, The Mall at Cribbs Causeway and University of the West of England. A quarter of employees work outside of the Bristol area in Bath, Gloucester, Swindon, Cardiff or Newport.

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Figure 2‐3: SusCom staff home postcode locations (source: North Bristol SusCom Postcode Factsheet, 2012)

Existing models indicate that there are around 2,500 trips in both the AM and PM peaks respectively that are travelling to or from the eastern fringe of Bristol to the motorway network. This traffic is currently accessing via Junction 19, typically through the Hambrook section of the A4174, or are travelling on the A420, or B4465 through Pucklechurch & Hinton to or from Junction 18.

1 North Bristol SusCom is a group of major employers, located in North Bristol, promoting sustainable commuting for employees and students.

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SECTION 2 – LOCAL TRANSPORT SITUATION Information about the origin‐destination of trips in the area has been taken from the GBATS2 transport model, and is shown in Table 2.3. The data shows that there is a strong demand from east Bristol to central and west Bristol.

Average Daily Vehicle To Movements

Central and Wales & Eastern Bristol East of Bristol North of Bristol Western Bristol Severn Beach

Central and 95,000 27,000 9,000 21,000 Western Bristol

Eastern Bristol 85,000 6,000 4,000 7,000

From Wales & Severn 28,000 9,000 12,000 10,000 Beach

East of Bristol 13,000 6,000 12,000 5,000

North of Bristol 24,000 8,000 9,000 5,000

Table 2‐4: Average daily movements between selected areas (GBATS Model 2013) 2.3 Transport Problems and Factors The primary highway corridors into and across Bristol are congested and continued traffic growth threatens the future economic prosperity of the sub‐region. The West of England’s current share of national economic growth (GVA) is the highest of any core city region at 3.1%. The overall vision is to build on this economic growth through a range of interventions including improving access to major employment sites for the skilled workforce. The sub‐region is also set for further population growth, which is expected to exceed 1.1 million by 2026. Planning for this growth means the sub‐region needs to make sure its transport infrastructure is not only fit‐for‐purpose, but has the ability to respond to increasing demand and, therefore, maximise potential for continued economic growth. 2.4 Transport modelling Draft Full details of the transport modelling undertaken for the scheme is reported in the Transport Modelling Report in the Appendix. Modelling was undertaken for Western Option 1, Central Option 2 and Eastern Options 3a & b. Combined Options 4a‐c were discounted early in the study before substantial transport modelling had been undertaken and thus results for these are not presented.

2 GBATS (Greater Bristol Area Transport Study model) is a strategic transport demand model of the greater Bristol area and includes both highways and public transport. This model has been developed to be compliant with, and has been used to assess, a number of schemes in the area that have been given funding approval by the DfT. GBATS produces matrices of trips and journey data (time, cost and distance) for three time periods (AM peak, inter‐peak and PM peak hours) and several modes (car, bus, rail and bus rapid transit) also subdivided by user class (commuting, other home based trips and business journeys) and income level of travellers.

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SECTION 2 – LOCAL TRANSPORT SITUATION

Figure 2‐4: Impact of congestion in and around the study area 2013 Figure 4.2 presents 2013 congestion data and Figure 4.3 presents the expected congestion levels in 2036. This data has been extracted from the GBATS model. The size of highlighted junctions and links indicate near or overcapacity junctions and the quantity of traffic affected.

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Figure 2‐5: Impact of congestion in and around the study area 2036

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SECTION 2 – LOCAL TRANSPORT SITUATION Collision data for key corridors in the study area is presented in Figure 4.4.

Figure 2‐6: Collisions in and around the study (2011 to 2015) The network demonstrates low resilience and collisions or works can cause severe congestion in a wide area. Traffic modelling for the JTS indicates that congestion on the A4174 and M32/M4 will continue to increase with delays on the routes discussed in the previous section predicted to double by 2036. The modelling indicates that substantial queuing onto the M4 mainline at J19, which already happens around once a week, will become a daily occurrence by 2036. Traffic demand in the vicinity of the proposed scheme is forecast to increase around 20% by this year. Table 4.1 below shows traffic changes on key links between 2013 and 2026 for the AM and PM peak hours. Draft

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SECTION 2 – LOCAL TRANSPORT SITUATION

Link AM Change PM Change

M4 J19 to J20 +26% +22%

M4 J20 to J19 +16% +16%

M4 J19 to J18 +19% +29%

M4 J19 to J18 +17% +20%

M32 J1 to M4 J19 +18% +23%

M4 J19 to M32 J1 +5% +5%

Wick Wick to Bromley Heath +1% +27%

Bromley Heath to Wick Wick +28% +8%

Rosary to Lyde Green +10% +18%

Lyde Green to Rosary +22% +13% Table 2‐5: Increases in demand on key motorway and ring road links (Source: GBATS)

The 2036 reference case modelling also indicates several junctions on the A4174 will be over capacity, including Bromley Heath, Wick Wick, Lyde Green and Deanery Rd. Blocking‐back from the M32 onto the M4 will increase in severity in both peak periods. Analysis of the model routing is suggesting the delays are causing some traffic to avoid the Ring Road and re‐route onto less suitable alternative roads, with greater than 100% increases on Filton Road, Cleeve Road and Bromley Heath Road, as traffic avoids the A4174 Hambrook junction in particular. This will have an adverse impact on the environment and road safety, as congestion on the main roads pushes traffic onto unsuitable local highways. Across the wider network, performance is forecast to deteriorate, with an overall increase of 15% in traffic demand in both peak periods leading to delay increasing by 31% in the AM and 40% in the PM. Increased demand will also turn increase journey time variDraftability.

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SECTION 3

3Summary

This section provides information to allow Highways England to compare the performance of this scheme with other schemes. Summary tables are only provided for Western Option 1 and Eastern Option 3A as Central Option 2 and the other Eastern options were eliminated during the Option Assessment process. In this section, Captial and Operational Expenditure estimates provided by Highways England have been used. 3.1 ComMA Summary Tables High level benefits and costs (£000’s) Western Option Eastern Option A Present Value of Benefits (initial) £1,031,974 £1,051,303 Present Value of Benefits (adjusted) £1,184,132 £1,234,823 Present Value of Costs £235,130 £230,494 Initial BCR 4.39 4.56 Adjusted BCR 5.04 5.36

Sources of Costs

Costs of the scheme result from the construction of the scheme consisting of a D2AP link between the A4174 and the M4, a new motorway junction, extension of the smart motorway system between M4 J19 and the proposed J18a, improvements to the A4174 between the A4 and the new link and associated land and structures costs.

The western option has notable costs due to need to move the motorway mainline to fit the junction and a greater number of junctions improved along the A4174.

Sources of Benefits

Major sources of benefits are found in travel between the north eastern areas of Bristol and strategic locations, i.e. west (Newport, Cardiff) and east (Swindon, Reading, London) along the M4 and north on the M5 (Gloucester,Draft Cheltenham, Birmingham). Benefits are also found on movements within Bristol with strategic trips able to get to the M4 more directly.

Identified sources of disbenefits are strategic trips passing Bristol on the M4 due to the increased M4 link flows and the new junction reducing speeds. There are also lesser disbenefits found in short distance trips within the eastern fringe of Bristol.

Demand Growth along the Route (Do Minimum) Link AADT (opening year) AADT (design year) AADT change (%) M4 - J20 to J19 43594 52506 20% M4 - J19 to J20 47548 55882 18% M4 - J19 to J18 43594 52506 20% M4 - J18 to J19 47548 55882 18% M32 - J1 to M4 J19 41145 48430 18% M32 - M4 J19 to J1 47184 51557 9% M32 - J2 to J1 38018 42780 13% M32 - J1 to J2 41478 44846 8% Distance-weighted Average 48610 57430 18%

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SECTION 3 – SUMMARY

Demand Growth along the Route (Western Option 1) Link AADT (opening year) AADT (design year) AADT change (%) New Link - A4174 to M4 19833 24296 23% New Link - M4 to A4174 21704 26480 22% M4 - J20 to J19 83095 96005 16% M4 - J19 to J20 75233 88536 18% M4 - J19 to J18a 65339 77628 19% M4 - J18a to J19 63995 75032 17% M4 - J18a to J18 44304 52067 18% M4 - J18 to J18a 48845 56168 15% M32 - J1 to M4 J19 39400 45199 15% M32 - M4 J19 to J1 46631 50900 9% M32 - J2 to J1 38170 43118 13% M32 - J1 to J2 42323 45940 9% Distance-weighted Average 54431 63649 17%

Demand Growth along the Route (Eastern Option 3a) Link AADT (opening year) AADT (design year) AADT change (%) New Link - A4174 to M4 12826 17274 35% New Link - M4 to A4174 13736 17532 28% M4 - J20 to J19 75172 87764 17% M4 - J19 to J20 71690 85238 19% M4 - J19 to J18a 50422 61975 23% M4 - J18a to J19 52813 64002 21% M4 - J18a to J18 46533 55170 19% M4 - J18 to J18a 50204 57869 15% M32 - J1 to M4 J19 40975 46609 14% M32 - M4 J19 to J1 48201 52747 9% M32 - J2 to J1 37829 42865 13% M32 - J1 to J2 41647 45640 10% Distance-weighted Average 48763 58114 19%

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SECTION 3 – SUMMARY Key Monetised Benefits and Costs – Western Option 1

Category Benefits and costs in £’000 (PV) Business Users Journey Time Savings 481783 Vehicle Operating Costs -18279

Non-Business users Journey Time Savings 629489 Vehicle Operating Costs -98494

Reliability Business Reliability 48178 Non-business Reliability 62949

Safety Safety Not monetised at this stage

Environmental Impacts Noise Not monetised at this stage Local Air Quality Not monetised at this stage Greenhouse Gases -14000 Landscape Not monetised at this stage

Wider Economic Impacts Agglomeration 103845 Market Competition 46349 Dependent Development - Labour Supply 1965

Customer Impact Traffic delays due to Construction Not monetised at this stage Traffic impacts due to Maintenance Not monetised at this stage Journey Quality DraftNot monetised at this stage Developer contributions Developer contributions 0

Other Impacts Indirect tax Revenues 66394

Costs Cost to Broad Transport Budget 235130 Cost savings(where relevant)

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SECTION 3 – SUMMARY Key Monetised Benefits and Costs – Eastern Option 3A

Category Benefits and costs in £’000 (PV) Business Users Journey Time Savings 502076 Vehicle Operating Costs -5742

Non-Business users Journey Time Savings 630921 Vehicle Operating Costs -109957

Reliability Business Reliability 50208 Non-business Reliability 63092

Safety Safety Not monetised at this stage

Environmental Impacts Noise Not monetised at this stage Local Air Quality Not monetised at this stage Greenhouse Gases -14000 Landscape Not monetised at this stage

Wider Economic Impacts Agglomeration 131503 Market Competition 49643 Dependent Development - Labour Supply 2374

Other Impacts Indirect tax Revenues 62619

Costs Cost to Broad Transport Budget 230494 Cost savings(where relevant)

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SECTION 3 – SUMMARY Key quantified benefits / costs – Western Option 1 Category Quantified impacts Units Journey times (average saving per journey on Journey Time Savings scheme sections in minutes)

Safety

Accidents Not quantified at this stage (total number saved) Fatalities Not quantified at this stage (total number saved) Seriously injured Not quantified at this stage (total number saved) Slightly injured Not quantified at this stage (total number saved)

Environmental Impacts Number of Noise important areas (number) affected Names of AQMAs N/A (names) Change in NOx emissions Not quantified at this stage (tonnes) Change in PM10 emissions Not quantified at this stage (tonnes) Change in greenhouse gas 641484 non-traded (tonnes CO2e) emissions 3131 traded

Customer Impact: Totals (total loss on scheme sections in Traffic delays due to Construction Not quantified at this stage hours) (total impact on scheme Traffic impacts due to Maintenance Not quantified at this stage sections in hours)

Customer Impact: Per journey Traffic delays due to Construction (average loss per journey on Not quantified at this stage (cars) scheme sections in minutes) * Traffic delays due to Construction (average loss per journey on Not quantified at this stage (LGVs) scheme sections in minutes) * Traffic delays due to Construction (average loss per journey on Not quantified at this stage (HGVs) scheme sections in minutes) * Traffic impacts due to Maintenance (average impact per journey on DraftNot quantified at this stage (cars) scheme sections in minutes) * Traffic impacts due to Maintenance (average impact per journey on Not quantified at this stage (LGVs) scheme sections in minutes) * Traffic impacts due to Maintenance (average impact per journey on Not quantified at this stage (HGVs) scheme sections in minutes) *

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SECTION 3 – SUMMARY Key quantified benefits / costs – Eastern Option 3A Category Quantified impacts Units Journey times (average saving per journey on Journey Time Savings scheme sections in minutes)

Safety

Environmental Impacts Number of Noise important areas (number) affected Names of AQMAs N/A (names) Change in NOx emissions Not quantified at this stage (tonnes) Change in PM10 emissions Not quantified at this stage (tonnes) Change in greenhouse gas 629889 non traded (tonnes CO2e) emissions 2910 traded

Customer Impact: Per journey Traffic delays due to Construction (average loss per journey on Not quantified at this stage (cars) scheme sections in minutes) * Traffic delays due to Construction (average loss per journey on Not quantified at this stage (LGVs) scheme sections in minutes) * Traffic delays due to Construction (average loss per journey on Not quantified at this stage (HGVs) Draftscheme sections in minutes) * Traffic impacts due to Maintenance (average impact per journey on Not quantified at this stage (cars) scheme sections in minutes) * Traffic impacts due to Maintenance (average impact per journey on Not quantified at this stage (LGVs) scheme sections in minutes) * Traffic impacts due to Maintenance (average impact per journey on Not quantified at this stage (HGVs) scheme sections in minutes) *

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SECTION 3 – SUMMARY Strategic Outcome – Western Option 1 Scheme Strategic Scheme Contribution – KPI Contribution - Outcome Qualitative Quantitative Reduction in congestion around M4 J19 and M32 J1 as well as reduction in queuing from slip roads onto the mainline is expected Making the The number of KSIs on to result in a reduction in collisions, Not quantified network safer the SRN. however the overall traffic increase at this stage and creation new conflict points may increase collisions On balance, a slight adverse impact is expected. Noise: Number of Noise Important Areas There are three SSSIs within 2km mitigated. of the scheme. No field surveys Delivery of have been undertaken at this stage better but it is expected that there is the

environmental Biodiversity: Delivery of potential for a range of outcomes improved biodiversity, as protected/notable species to be set out in the present and thus for impact to Company’s Biodiversity these. Action Plan Helping This option retains and improves cyclists / the existing shared paths along the walkers and The number of new and affected A4174, it also extends the

other upgraded crossings paths along the proposed link to vulnerable link with NCR 410 provided better users accessibility to Yate

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SECTION 3 – SUMMARY Strategic Outcome – Eastern Option 3A Scheme Strategic Scheme Contribution – KPI Contribution - Outcome Qualitative Quantitative Reduction in congestion around M4 J19 and M32 J1 as well as reduction in queuing from slip roads onto the mainline is expected Making the The number of KSIs on to result in a reduction in collisions, Not quantified network safer the SRN. however the overall traffic increase at this stage and creation new conflict points may increase collisions On balance, a slight adverse impact is expected. There are two SSSIs within 2km of Noise: Number of Noise the scheme. No field surveys have Important Areas been undertaken at this stage but it mitigated. is expected that there is the Delivery of potential for a range of better protected/notable species to be environmental Biodiversity: Delivery of present and thus for impact to outcomes improved biodiversity, as set out in the these. Given the greater and more Company’s Biodiversity rural nature of the land required it Action Plan is expected that there is greater potential in this option for impact. This option retains and improves the existing shared paths along the Helping affected A4174. The network of cyclists / paths near Pucklechurch and along Estimated 18 walkers and The number of new and the new link will also be retained RoW affected other upgraded crossings and improved. A number of rights along new link vulnerable of way will need to be diverted users across the new link, it is not known at this stage the level of usage and the required diversions.

3.2 Recommendation The business case for the scheme needs to: Draft  Be supported by a robust ‘case for change’ that fits with wider public policy objectives ‐ the ‘Strategic Case’;  Demonstrate value for money ‐ the ‘Economic Case’;  Be commercially viable ‐ the ‘Commercial Case’;  Be financially affordable ‐ the ‘Financial Case’; and  Be achievable ‐ the ‘Management Case’

The following table shows summary of the transport case for the Western and Eastern Options.

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SECTION 3 – SUMMARY Case (as prescribed in Western Option (1) Eastern Option (3a) guidance)

Strategic Case Good fit to wider public policy of Good fit to wider public policy of economic growth and relieving economic growth and relieving congestion. Significant reduction in delay congestion. Significant reduction in delay and accidents. and accidents.

Financial Case £428 million (Outturn) £376 million (Outturn)

Economic Case – Economy Very High Value for Money Very High Value for Money

Economic Case ‐Environment Adverse impact to natural environment, Adverse impact to natural environment, historic environment in some places, e.g historic environment in many places, Folly Brook such as around Pucklechurch, the AONB and Green Belt.

Economic Case – Potential facilitation of 5,700 jobs Potential facilitation of 2,200 jobs Regeneration

Economic Case – Gross Value Added (GVA) Gross Value Added (GVA) Regeneration £449m £174m

Economic Case – People Low adverse impact to people and High adverse impact to people and communities, in many places communities, in some places

Management Case‐ Delivery Both options are considered to be Both options are considered to be Case achievable and have a management case. achievable and have a management case. Subject to dependencies: these include Subject to dependencies: these include prioritisation within the West of England prioritisation within the West of England major scheme programme; inclusion major scheme programme; inclusion within the RIS programme and associated within the RIS programme and funding allocation. A Development associated funding allocation. A Consent Order will be required. Western Development Consent Order will be option considered to have a stronger required. Eastern option considered to case. have a weaker case.

Management Case – Public 74% of people support a new J18a, of 74% of people support a new J18a, of Acceptability which 51% of people who completed the which 17% of people who completed the questionnaire preferred this route questionnaire preferred this route, with strong objections to the Eastern routes.

Commercial Case The scheme is considered commercially The scheme is considered commercially viable and aligns with Highways England viable and aligns with Highways England Project Control Framework processes. DraftProject Control Framework processes.

RECOMMENDATION: The Western Option (1) is recommended as the best performing option, based on the assessment work undertaken for the Strategic Outline Business Case. The Western Option offers a greater potential to facilitate additional jobs, and it has less environmental challenges than the Eastern Option. For the scheme to be progressed it needs to be prioritised by Highways England against national schemes and included in the RIS programme. If prioritised, the following work would be required by Highways England:  Further scheme development work  Outline Business and associated design and tendering work

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SECTION 3 – SUMMARY  Development Consent Order (including planning, environmental and land consents)  Full Business case  Construction of the scheme.

3.3 Assumptions and Caveats The work has been conducted in line with the WebTAG requirements for a Strategic Outline Business Case (SOBC) and is therefore considered to be sufficient for PCF Stage 0 analysis, however for both these stages the appraisal will have a number of assumptions and caveats and these are summarised in this section. As is recommended for this stage, the work made best use of existing transport models with only proportional adjustments. For this study the GBATS4M transport model was considered to be the most appropriate starting point. Network adjustments were made to the reference case forecast year in the area local to the scheme and the mode growth constraints were updated to Tempro 7.2. Notable limitations are considered as followed:  The model has a base year of 2013;  Available forecast years are 2021 & 2036 so construction is represented as completed by 2021 for the purposes of economic analysis;  The study area is on the edge of the GBATS4M simulation area.  The model economics is based on TUBA 1.9.7 Draft

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Appendix A

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M4 Junction 18A Link Study‐ Strategic Outline Business Case ‐ Modelling Report

Prepared for South Gloucestershire Council and Highways England

March 2018 Draft

1 The Square Temple Quay Bristol BS1 6DG

Draft

Document history

M4 Junction 18a Link Study Transport Modelling Report

This document has been issued and amended as follows:

Version Date Description Created by Verified by Approved by 001 01.03.18 Final Report JB HS HS

Draft

Contents

Section Page Introduction ...... 1‐1 1.1 Study Overview ...... 1‐1 Available Models ...... 2‐1 2.1 Available Models ...... 2‐1 Modelling Approach ...... 3‐1 3.1 Business Case Modelling ...... 3‐1 3.1.1 Strategic Modelling ...... 3‐1 3.1.2 Junction Modelling...... 3‐1 3.2 Final Options Evaluated ...... 3‐2 Strategic Results ...... 4‐1 4.1 Strategic Modelling Overview ...... 4‐1 4.1.1 Overall Network Statistics...... 4‐1 4.1.2 Highway Flows ...... 4‐2 4.1.3 Highway Travel Times ...... 4‐7 4.1.4 Movements Using the Proposed Link ...... 4‐10 4.1.5 Transport User Benefits ...... 4‐13 Detailed Junction Results ...... 5‐21 5.1 Common Section A4174 Hicks Gate to Siston Hill ...... 5‐21 5.1.1 Hicks Gate ...... 5‐21 5.1.2 Kingsfield ...... 5‐22 5.1.3 Woodstock ...... 5‐23 5.1.4 Deanery ...... 5‐23 5.1.5 Siston Hill ...... 5‐24 5.2 Western Option ...... 5‐25 5.2.1 Dramway ...... 5‐25 5.2.2 Rosary ...... 5‐26 5.2.3 Lyde Green ...... 5‐26 5.2.4 Westerleigh Road ...... 5‐27 5.3 Eastern Option ...... 5‐28 5.3.1 Dramway ...... 5‐28 Draft 5.4 Merge/Diverge flow & type requirements ...... 5‐29 Sensitivity Tests ...... 6‐33 6.1 Bristol South Ring Road ...... 6‐33 6.2 Link to Yate ...... 6‐33

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SECTION 1 Introduction

The four West of England Councils have produced a West of England Joint Transport Study (JTS), published in October 2017. The JTS has identified a need for a new junction between M4 Junction 18 and Junction 19, and an associated link road to the A4174, north Bristol. The document states that the scheme will help address problems at Junction 19 and unlock economic growth in the East Fringe and Yate. The JTS proposes a package of highway and public transport schemes, including a road connection to a new junction on the M4 from the A4174 Ring Road, along with an extension of the ‘smart’ motorway management scheme on the M4. The M4 Link is referenced in the South Gloucestershire Adopted Core Strategy as follows: “The Council is committed to the long‐term realisation (beyond 2027) of a new link road from the A4174 Ring Road to the M4 (between Junction 18 and 19) to relieve congestion to the M4 Junction 19, M32 Junction 1, the A4174 eastbound and within the communities of the north‐east Bristol fringe area. The Council will continue to make the case to the Highways Agency (now Highway England) and central government during the plan period.” Local MPs met with Transport Secretary Patrick McLoughlin in January 2016 to present the case for building Junction 18a at Emersons Green1. The group Gateway2Growth, believe the scheme could open up at least 7,000 jobs at the Emersons Green Enterprise Area, as well as taking the pressure off the M4, M32 and other major roads around north and east Bristol, particularly the A4174. 1.1 Study Overview

This study involves the assessment of options for a new motorway junction between the M4 Junction 19 and M4 Junction 18, and provision of a Link to the A4174, north Bristol. The study will:  Identify the exact nature of the problems and the need for an intervention utilising extant and emerging information;  Identify options for increasing capacity and resilience on this part of the transport network across all surface transport modes;  Examine the technical feasibility Draftof any new transport improvements to establish in principle where solutions are possible and whether there are significant environmental or other constraints that would make solutions impractical; and  Use DfT’s Early Assessment and Sifting Tool to reduce a ‘long’ list of options to a ‘short’ list for fuller appraisal. This report sets out the transport modelling methodology for the M4 Junction 18a Link Strategic Outline Business Case. It sets out both the transport modelling to be used directly in the business case economics and additional supporting transport modelling to inform other aspects of the scheme. WebTAG guidance indicates that the modelling undertaken should be proportionate to the stage of the study and that, for Stage 1, existing models are likely to be sufficiently accurate.2 The study area and estimated area of impact are shown in Figure 1‐1.

1 http://www.bristolpost.co.uk/transport‐secretary‐meeting‐offers‐fresh‐hope‐new/story‐28579793‐detail/story.html

2 https://www.gov.uk/government/publications/webtag‐tag‐guidance‐for‐the‐technical‐project‐manager

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SECTION 1 – INTRODUCTION

Figure 1‐1: Study Area Draft

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SECTION 2

2Available Models 2.1 Available Models 2.1.1.1 GBATS4 GBATS (Greater Bristol Area Transport Study model) is a strategic transport demand model of the greater Bristol area and includes both highways and public transport. This model has been developed in accord with WebTAG guidance and has been used to assess a number of schemes in the area that have been given funding approval by the DfT. GBATS produces matrices of trips and journey data (time, cost and distance) for three time periods (AM peak, inter‐peak and PM peak hours) and several modes (car, bus, rail and bus rapid transit) also subdivided by user class, namely: commuting / other home based trips by income level and business journeys. highway modelled hours are 08:00‐09:00 AM peak, average 10:00‐16:00 interpeak and 17:00‐18:00 PM peak. Both peak periods have the preceding pre‐peak hour modelled in order to generate congestion present at the start of the peak period. Forecast years are 2021 and 2036 GBATS version 4 was validated to 2013 flows, this model utilises SATURN for highway assignment and EMME/4 for public transport and demand modelling. The demand model employs an incremental pivot point structure and has been built to WebTAG guidance. The extent of the model is shown in Figure 2‐1.1 and the zoning system in 2.2 below. It can be seen that the area of the proposed scheme is within the simulation area of the model along with the extent of the A4174 to the south likely to be impacted by the change. Draft

Figure 2‐1: GBATS modelled area

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SECTION 2 – AVAILABLE MODELS

Figure 2.2: GBATS Zoning System Draft

Figure 2.3: GBATS 4 Calibration and Validation Screenline and Cordon Count Sites (GEH for AM Peak)

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SECTION 2 – AVAILABLE MODELS

Figure 2.4: GBATS 4 Available Count Data

In the most recent update of the model, the validation was focused on the areas being affected by the MetroWest project, which includes improvement to services to Yate. A plot of the GEH values for the AM peak of the counts used for model calibration and validation screenlines and cordons is shown in 2.3; the PM peak shows a similar level of validation. Detailed tables from the model calibration indicate counts along the A4174 Ring Road are generally within GEH 5 of the observed data from permanent ATC sites, the location of all available 2013 count data locations used in GBATS are shown in 2.4. The reported journey time validation along the A4174 in both directions and peaks between M32 J1 and the Hicks Gate roundabout demonstrates a good fit. Model development and validation documentation is available on request. Atkins Joint Transport Study modelling Draft The modelling undertaken for the Joint Transport Study (JTS) was undertaken based on the above version of GBATS. Some network changes were made to the Do Minimum models to reflect changes in schemes completed since 2013 and to those planned for future years as well as new planned schemes. The JTS undertook a preliminary assessment of the need for a M4 Junction J18a and Link. 2.1.1.2 South West Regional Transport Model (SWRTM) SWRTM is part of the Regional Transport Model suite commissioned by Highways England to progress the Road Investment Strategy (RIS) program. Arup, supported by a Mott MacDonald Sweco JV, developed the model. The RTMs use the SATURN software for highway assignment and will use DIADEM to handle the demand model element. Model development across the RTMs used a common process overseen by a number of Technical Consistency Groups. Model supply consists of simulation modelling for all of the Strategic Road Network (SRN), major parallel rural routes and on connecting rural roads two to three junctions away from the SRN. Urban

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SECTION 2 – AVAILABLE MODELS areas outside the influence area of the SRN are represented as fixed speed network based on trafficmaster data. The network coverage of the model is shown in 2.5.

Figure 2.5: SWRTM Network Coverage (Source: SWRTM Draft MVR) Model demand is based on mobile phone data supplemented with a variety of other sources including 2011 census travel to work, National Travel Survey (NTS), National Trip End Model (NTEM). The model consists of 1901 zones which are largely based on Census Middle Layer Super Output Areas (MSOA), the zoning system is shown in 2.6. Draft

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SECTION 2 – AVAILABLE MODELS

Draft

Figure 2.6: SWRTM Zoning System (Source: SWRTM Draft MVR) The model, along with the other RTMs, was a work in progress. Validated base highway assignment models were available, but the demand model, along with forecast models and processes are currently in development and are unlikely to be available for use in this stage of the M4 J18a study. In relation to the scheme proximity, for supply, the coding standards employed mean that the A4174 clockwise of the Wick Wick Roundabout is considered as part of the Bristol urban area and is

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SECTION 2 – AVAILABLE MODELS therefore coded as fixed speed links without junction modelling. For demand the MVR indicates that while the overall model calibration is reasonable, there are some short‐comings in the AM and PM periods on the M4 between J18 and J19 (2.7). Inspection of the calibration dashboard indicates these failures are all where flow is lower in the model than the observed flow.

Figure 2.7: SWRTM Flow Calibration PM Period (Source: SWRTM Draft MVR) Model development and validation documentation would be available from the SWRTM team on request. Draft

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SECTION 3

3Modelling Approach 3.1 Business Case Modelling 3.1.1 Strategic Modelling 3.1.1.1 Model Selection The primary modelling to inform the business case and economics at this strategic stage has been undertaken in GBATS4 using the model largely as currently developed. The model has been built to WebTAG standards, includes a public transport and variable demand model and has previously been used to successfully support scheme business cases. The study area is fully covered by the simulation modelling area of GBATS4 and the model shows reasonable flow and journey time validation in the area. It is considered that this model is a satisfactory tool for this early stage of assessment. 3.1.1.2 Model Supply Changes Strategic modelling was undertaken in the GBATS4 modelling suite. GBATS4M was used as the starting point for the model with additional coding and changes from the work undertaken by Atkins for the JSP/JTP on behalf of the West of England councils were included where appropriate for inclusion in a Core Scenario as defined in WebTAG. Additional network was adjusted to enhance detail and zone loading for the Lyde Green development. Significant changes and schemes included in the Do Minimum model were:  M49 Severnside Junction;  Changes to reflect the managed motorway as built;  Signalisation of Rosary roundabout on A4174; and,  Adjustment of network and zone loading of Lyde Green & Science Park developments. 3.1.1.3 Model Demand Changes The following changes to the model demand and the demand modelling parameters were made:  ~100,000 sqm of industrial land use in the Lyde Green development changed to ‘More than Likely’ classification and thus included in the Core Scenario Draft  Forecast constraints updated to TemPRO 7.2 figures. 3.1.1.4 Do Something Models Scheme coding was undertaken in line with the network coding standards used in the GBATS model. Demand inputs are identical in all future models. 3.1.2 Junction Modelling Junction modelling and design formed an iterative process with the strategic modelling. This is shown in Figure 3‐1. Initially the strategic model was run with indicatory coding for the junctions to provide realistic delays for within capacity operation. These flows then formed the basis of the initial junction design and analysis in the LinSig software. Junction designs were then implemented in the strategic model, flow reextracted and input into the LinSig models in order to ensure sufficient junction capacity.

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SECTION 3 – MODELLING APPROACH

Model Options in GBATS

Scheme junctions use indicatory coding to provide sufficient capacity and realistic delay.

Extract forecast flows and model Design/Revise Junction junction designs in LinSig

Model Finalised Options in GBATS

Scheme junctions coded to accurately reflect layouts from design process. Figure 3‐1: Junction Modelling and Design Process LinSig modelling was undertaken with the following standards:  Software version: 3.2.29.0.  Saturation flows: Calculated from geometry with RR67  Intergreen times calculated using TAL 01/06  Minimum pedestrian green and intergreen times calculated using TAL 05/05  Left turn priority intercept and slope values calculated using appropriate PICADY or ARCADY formulae based on geometry Draft  Right turn across traffic intercept set to recommended default of 1439pcu/hr with slope of 1.09  Signal timings determined by optimised by PRC in combination with queue limits on internal links. Manual refinement of timings were applied where necessary. For each junction improvement, signalised crossroads or T junctions were investigated initially, followed by a throughabout/’hamburger’ arrangement. 3.2 Options Modelled Combined Options 4a‐c had been eliminated due to practicality and affordability reasons before the refined strategic modelling was undertaken. As such, results for these options are not presented. Central Option 2 was later also eliminated due to practically and affordability reasons, modelling that was undertaken for this option has been reported for completeness.

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SECTION 3 – MODELLING APPROACH Improvements to the A4174 between Hick’s Gate and the Siston Hill roundabout were common to each option. These consist of a displaced right turn at Hick’s Gate with the other roundabouts converted to hamburgers. Also common to the options was the extension of the ‘smart motorway’ scheme as far as the proposed junction and the reversion of eastbound traffic over J19 to three lanes from two due to the reduction in traffic leaving as a result of the scheme. Western Option 1 In this option, Westerleigh Rd from Lyde Green Roundabout is used as the link to the new junction which is located approximately 200m to the north of the existing motorway. This option requires the relocation of the motorway mainline in order to fit the junction in due to development constraints south of the existing mainline. Option 1 consists of a standard grade‐separated signalised gyratory which connects back to Westerleigh Rd to the north. The link to the south is widened to a minimum two lane dual carriageway with the junction with Folly Brook Road and the Science park improved to a signalised crossroads. In addition, Lyde Green Roundabout is converted to a throughabout while Rosary and Dramway are converted to signalised junctions. Central Option 2 In this option, the new link road connects to the Dramway roundabout, which is changed to a signalised junction. At the M4 it joins via an arrangement of free flow slips. The link road is a two lane dual carriageway. Eastern Option 3A In this option, the link road connects to the south of the Dramway Roundabout via south facing slip roads. A proposed priority roundabout links to the B4465 (along which access to Emersons green would be provided via the existing Dramway Roundabout) and Siston Lane. From this, the link road passes to the east of Pucklechurch where it joins the B4465 to the north of Pucklechurch via another priority based roundabout. The link then continues north to the M4 where access is provided via a standard grade‐separated gyratory as in Option 1 over the existing alignment of the M4. Access is also provided to the north via Westerleigh Road. Draft

3‐3 Draft

SECTION 4

4Strategic Results 4.1 Strategic Modelling Overview This section will cover the more strategic impacts of the scheme treating the options in a comparative sense. For the Eastern Option, the 3A variant is used as representative. 4.1.1 Overall Network Statistics Highway Network Statistics Highway network statistics are shown in Table 4‐1 to Table 4‐3 below. The first table shows the Base year and the Do Minimum models. It is clear that, as a result of the increased traffic demand there is a significant increase in queues and delays, with delays from overcapacity queuing (traffic unable to traverse the network in the assigned hour) doubling and total delay increasing by around one third in the peak hours.

Table 4‐1: Base Year (2013) and Do Minimum (2036) Highway Statistics Statistic Base Do Minimum

AM IP PM AM IP PM

Over‐Capacity Queues (pcuhr) 1362 23 1180 2381 97 2013

Total Delay (pcuhr) 9490 4881 9009 12511 6545 11798

Total Travel Time (pcuhr) 27149 18861 26956 33278 23525 32557

Travel Distance (km) 1142452 917589 1172089 1340746 1120130 1360933

Trips Loaded (pcu) 125630 106561 124898 147203 129307 144114

Average Travel Time (min) 13.0 10.6 12.9 13.6 10.9 13.6

Average Travel Distance (km) 9.1 8.6 9.4 9.1 8.7 9.4

Average Speed (kmhr‐1) 42.1 48.7 43.5 40.3 47.6 41.8

Table 4‐2: Option (2036) Highway Statistics Draft Statistic Western Option 1 Central Option 2 Eastern Option 3A

AM IP PM AM IP PM AM IP PM

Over‐Capacity Queues (pcuhr) 2024 87 1744 1933 73 1656 2082 83 1794

Total Delay (pcuhr) 12238 6511 11709 12196 6451 11509 12240 6468 11565

Total Travel Time (pcuhr) 33294 23604 32629 33347 23574 32538 33484 23636 32661

Travel Distance (km) 1374948 1134225 1382634 1383323 1136702 1391845 1383677 1134880 1391335

Trips Loaded (pcu) 147483 129268 144258 147525 129238 144331 147443 129241 144255

Average Travel Time (min) 13.5 11.0 13.6 13.6 10.9 13.5 13.6 11.0 13.6

Average Travel Distance (km) 9.3 8.8 9.6 9.4 8.8 9.6 9.4 8.8 9.6

Average Speed (kmhr‐1) 41.3 48.1 42.4 41.5 48.2 42.8 41.3 48.0 42.6

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SECTION 4 – STRATEGIC RESULTS

Table 4‐3: Proportional Change from Do Minimum Statistic Western Option 1 Central Option 2 Eastern Option 3A

AM IP PM AM IP PM AM IP PM

Over‐Capacity Queues (pcuhr) ‐15.0% ‐10.4% ‐13.3% ‐18.8% ‐24.6% ‐17.7% ‐12.5% ‐14.4% ‐10.9%

Total Delay (pcuhr) ‐2.2% ‐0.5% ‐0.8% ‐2.5% ‐1.4% ‐2.5% ‐2.2% ‐1.2% ‐2.0%

Total Travel Time (pcuhr) 0.0% 0.3% 0.2% 0.2% 0.2% ‐0.1% 0.6% 0.5% 0.3%

Travel Distance (km) 2.6% 1.3% 1.6% 3.2% 1.5% 2.3% 3.2% 1.3% 2.2%

Trips Loaded (pcu) 0.2% 0.0% 0.1% 0.2% ‐0.1% 0.2% 0.2% ‐0.1% 0.1%

Average Travel Time (min) ‐0.1% 0.4% 0.1% 0.0% 0.3% ‐0.2% 0.5% 0.5% 0.2%

Average Travel Distance (km) 2.4% 1.3% 1.5% 3.0% 1.5% 2.1% 3.0% 1.4% 2.1%

Average Speed (kmhr‐1) 2.5% 1.1% 1.4% 3.0% 1.3% 2.4% 2.5% 0.8% 1.9%

From the second and third tables, it can be seen that all three options result in a significant decrease in queueing at the end of the time period. There is between a 2 and 2.5% decrease in delay and around a 2.5 to 3% increase in the average speed. There is a similar increase in both total and average travel distance as the demand model responds to the decreased cost of travel by redistributing trips. The options also generally result in a slight increase in numbers of trips due to the trip frequency response of the demand model. Looking at the options individually, it can be seen that Central Option 2 shows the largest reductions in queueing and delay. This is likely a result of the direct slip road only nature of the connection to the M4. In the AM, the Western and Eastern Options show broadly similar reductions in delay though Eastern Option 3 shows a larger increase in travel distance and times, likely due to the longer link to the M4. In the PM peak, Western Option 1 shows a noticeably lower reduction in overall delay, as will be covered in subsequent results, this appears due to the additional traffic it encourages onto the M4 J20 to J19 mainline. 4.1.2 Highway Flows The tables below show the hourly flows, in pcu, in key links in the network for AM and PM peaks for the Do Minimum and the three options along with the proportionaDraftl changes compared to the Do Minimum. Difference plots of absolute flow changes are also provided of the area in Figure 4‐1 to Figure 4‐6. It should be noted that the rural roads further to the east of the A4174 are on the edge of the utilised model’s study area. As such proportional flow changes should be considered in a qualitative manner only. In traffic models, flow that does not either start in, end in, or go through the study area is not always included in the demand matrix, thus the further east from the A4174, the increased chance that the ‘Do Minimum’ flows are likely to be lower than would be otherwise forecast. There are a number of flow changes that are common to all three options:  Flows on A4174 clockwise of where the proposed link joins see significant increases in flow, particularly in the anticlockwise direction in the AM peak,  On the A4174 anticlockwise of the link, flows decrease and by greater amounts in the clockwise direction in the AM peak and anticlockwise in the PM peak.  Traffic on the M4 between J19 and J20 increases  Between J19 and the proposed J18a there is a significant increase in traffic

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SECTION 4 – STRATEGIC RESULTS  In the rural roads there are reductions in traffic through the centre of Pucklechurch and on the A420 through Wick.  There is an increase in traffic through Siston.

Table 4‐4: AM and PM Flows (pcu) on Key Links Location Do Minimum Western Option 1 Central Option 2 Eastern Option 3A AM PM AM PM AM PM AM PM A4174 ‐ M32 to Hambrook 2413 3237 1630 2654 2067 2962 2106 3110 A4174 ‐ Hambrook to M32 2921 2365 2560 1652 2742 1931 2808 2128 A4174 ‐ Bromley Heath to Wick Wick 1674 1947 794 1154 1216 1645 1259 1821 A4174 ‐ Wick Wick to Bromley Heath 1201 1306 1113 623 1161 942 1182 1074 A4174 ‐ Lyde Green to Rosary 1429 2031 1675 2084 497 942 708 1420 A4174 ‐ Rosary to Lyde Green 1818 1465 3178 1917 1512 995 1603 1057 A4174 ‐ Siston Hill to Deanery 1644 2383 1789 2502 2163 3056 1969 2819 A4174 ‐ Deanery to Siston Hill 1967 1612 2978 1994 3181 2246 3079 1969 M32 ‐ J1 to M4 J19 3922 4392 3639 4248 3351 4061 3582 4373 M32 ‐ M4 J19 to J1 4341 4010 4367 4345 4338 3974 4333 4139 M32 ‐ J2 to J1 3776 3488 3742 3540 3735 3540 3750 3541 M32 ‐ J1 to J2 3918 3438 3917 3583 4125 3463 4099 3480 M4 ‐ J20 to J19 5889 6690 7767 8308 7461 8211 6741 7582 M4 ‐ J19 to J20 6379 6736 7073 7371 7022 7265 6830 7030 M4 ‐ J19 to J18a 3774 4724 6044 6668 5496 6388 4853 5798 M4 ‐ J18a to J19 4509 4294 5836 5814 5766 5333 5307 4912 M4 ‐ J18a to J18 3774 4724 3927 4393 4205 4498 4360 4613 M4 ‐ J18 to J18a 4509 4294 4458 4264 4536 4455 4538 4534 New Link ‐ A4174 to M4 2158 1929 2341 1706 2282 1179 New Link ‐ M4 to A4174 2604 2237 2402 2718 1878 1990 Westerleigh Rd N of Science park NB 878 954 2158 1929 804 1024 447 557 Westerleigh Rd N of Science park SB 903 560 2604 2237 733 400 636 301 B4465 East Arm of Dramway EB 205 234 140 56 300 302 120 44 B4465 East Arm of Dramway WB 489 496 595 423 705 454 295 210 Main Rd ‐ Shortwood EB 216 133 191 181 199 164 136 80 Main Rd ‐ Shortwood WB 148 135 151 156 236 248 187 127 Siston Lane NB 475 271 556 242 656 294 754 363 Siston Lane SB 72 129 159 121 183 171 195 245 A420 in Wick EB 1253 520 1100 517 994 494 952 492 A420 in Wick WB 577 998 659 965 549 857 566 816 Abson NB 312 87 148 68 112 83 76 154 Abson SB 75 158 85 116 68 110 67 36 B4465 past Pucklechurch PO NB 451 270 328 186 303 205 13 15 B4465 past Pucklechurch PO SB 112 257 113 256 114 258 113 257 B4465 N of M4 NB Draft493 371 424 335 456 286 904 895 B4465 N of M4 SB 257 409 481 592 347 461 690 808

Table 4‐5: AM and PM Flows Changes compared with Do Minimum Location Western Option 1 Central Option 2 Eastern Option 3A AM PM AM PM AM PM A4174 ‐ M32 to Hambrook ‐32% ‐18% ‐14% ‐9% ‐13% ‐4% A4174 ‐ Hambrook to M32 ‐12% ‐30% ‐6% ‐18% ‐4% ‐10% A4174 ‐ Bromley Heath to Wick Wick ‐53% ‐41% ‐27% ‐15% ‐25% ‐6% A4174 ‐ Wick Wick to Bromley Heath ‐7% ‐52% ‐3% ‐28% ‐2% ‐18% A4174 ‐ Lyde Green to Rosary 17% 3% ‐65% ‐54% ‐50% ‐30% A4174 ‐ Rosary to Lyde Green 75% 31% ‐17% ‐32% ‐12% ‐28% A4174 ‐ Siston Hill to Deanery 9% 5% 32% 28% 20% 18% A4174 ‐ Deanery to Siston Hill 51% 24% 62% 39% 56% 22% M32 ‐ J1 to M4 J19 ‐7% ‐3% ‐15% ‐8% ‐9% 0% M32 ‐ M4 J19 to J1 1% 8% 0% ‐1% 0% 3% M32 ‐ J2 to J1 ‐1% 1% ‐1% 1% ‐1% 2% M32 ‐ J1 to J2 0% 4% 5% 1% 5% 1% M4 ‐ J20 to J19 32% 24% 27% 23% 14% 13% M4 ‐ J19 to J20 11% 9% 10% 8% 7% 4%

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SECTION 4 – STRATEGIC RESULTS

Table 4‐5: AM and PM Flows Changes compared with Do Minimum Location Western Option 1 Central Option 2 Eastern Option 3A AM PM AM PM AM PM M4 ‐ J19 to J18a 60% 41% 46% 35% 29% 23% M4 ‐ J18a to J19 29% 35% 28% 24% 18% 14% M4 ‐ J18a to J18 4% ‐7% 11% ‐5% 16% ‐2% M4 ‐ J18 to J18a ‐1% ‐1% 1% 4% 1% 6% Westerleigh Rd N of Science park NB 146% 102% ‐8% 7% ‐49% ‐42% Westerleigh Rd N of Science park SB 188% 300% ‐19% ‐29% ‐30% ‐46% B4465 East Arm of Dramway EB ‐32% ‐76% 46% 29% ‐42% ‐81% B4465 East Arm of Dramway WB 22% ‐15% 44% ‐8% ‐40% ‐58% Main Rd ‐ Shortwood EB ‐11% 36% ‐8% 23% ‐37% ‐40% Main Rd ‐ Shortwood WB 2% 15% 60% 84% 27% ‐6% Siston Lane NB 17% ‐11% 38% 9% 59% 34% Siston Lane SB 122% ‐6% 155% 33% 173% 90% A420 in Wick EB ‐12% ‐1% ‐21% ‐5% ‐24% ‐5% A420 in Wick WB 14% ‐3% ‐5% ‐14% ‐2% ‐18% Abson NB ‐53% ‐22% ‐64% ‐6% ‐76% 77% Abson SB 14% ‐27% ‐8% ‐31% ‐10% ‐77% B4465 past Pucklechurch PO NB ‐27% ‐31% ‐33% ‐24% ‐97% ‐94% B4465 past Pucklechurch PO SB 1% 0% 2% 0% 1% 0% B4465 N of M4 NB ‐14% ‐10% ‐8% ‐23% 83% 141% B4465 N of M4 SB 87% 45% 35% 13% 169% 98% These flow differences are also shown spatially in the figures below. The width of the line indicates the volume of change while the colour indicates if the Option decreases (blue) or increases (green) traffic against the Do Minimum case. Draft

Figure 4‐1: Change in Flow between Western Option 1 and Do Minimum in the AM. Increases in green, decreases in blue.

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SECTION 4 – STRATEGIC RESULTS

Figure 4‐2: Change in Flow between Western Option 1 and Do Minimum in the PM. Increases in green, decreases in blue. Draft

Figure 4‐3: Change in Flow between Central Option 2 and Do Minimum in the AM. Increases in green, decreases in blue.

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SECTION 4 – STRATEGIC RESULTS

Figure 4‐4: Change in Flow between Central Option 2 and Do Minimum in the PM. Increases in green, decreases in blue. Draft

Figure 4‐5: Change in Flow between Eastern Option 3 and Do Minimum in the AM. Increases in green, decreases in blue.

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SECTION 4 – STRATEGIC RESULTS

Figure 4‐6: Change in Flow between Eastern Option 3 and Do Minimum in the PM. Increases in green, decreases in blue. 4.1.3 Highway Travel Times A comparison of travel times has been made in two forms. First the travel time has been extracted along fixed routes such as the M4 and A4147. Secondly the travel time between specific origins and destinations has been analysed. This latter comparison does not consider fixed routes but uses a volume weighted average of the journey time between the origin and destination. Three fixed routes were assessed and are shown in Table 4‐6 and Table 4‐7. These considered travel times along the major roads in the proximity of the scheme:  Along the A4174 Ring Road betweeDraftn Hicks Gate and the Coldharbour Lane junction  Along the full length of the M32  Along the M4 between Junction 18 (A46 to Bath) and Junction 21 (M48 split between new & old Severn crossings) of the M4.

Table 4‐6: Fixed Route Travel Times AM Peak Hour Route Do Western Option 1 Central Option 2 Eastern Option 3A Minimum

Time Time Difference Time Difference Time Difference

M32 – Bond Street to M4 07:54 07:29 ‐00:25 07:26 ‐00:28 07:29 ‐00:25

M32 – M4 to Bond Street 14:28 14:41 00:13 15:12 00:44 15:06 00:38 A4174 – Hick’s Gate to 23:44 20:19 ‐03:26 20:33 ‐03:11 20:49 ‐02:55 Coldharbour Lane A4174 – Coldharbour Lane 17:08 18:00 00:52 17:13 00:05 16:23 ‐00:45 to Hick’s Gate

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SECTION 4 – STRATEGIC RESULTS

Table 4‐6: Fixed Route Travel Times AM Peak Hour Route Do Western Option 1 Central Option 2 Eastern Option 3A Minimum

Time Time Difference Time Difference Time Difference

M4 – J21 to J18 11:27 12:20 00:53 12:03 00:36 11:56 00:29

M4 – J18 to J21 12:04 12:43 00:39 12:40 00:36 12:32 00:28

Table 4‐7: Fixed Route Travel Times PM Peak Hour Route Do Western Option 1 Central Option 2 Eastern Option 3A Minimum

Time Time Difference Time Difference Time Difference

M32 – Bond Street to M4 06:55 06:58 00:03 06:57 00:02 06:58 00:03

M32 – M4 to Bond Street 09:06 09:31 00:25 09:14 00:08 09:10 00:04 A4174 – Hick’s Gate to 16:56 16:08 ‐00:47 16:19 ‐00:37 16:19 ‐00:37 Coldharbour Lane A4174 – Coldharbour Lane 19:49 19:17 ‐00:32 18:11 ‐01:38 17:44 ‐02:05 to Hick’s Gate M4 – J21 to J18 11:45 12:39 00:54 12:28 00:43 12:11 00:26

M4 – J18 to J21 11:59 12:36 00:37 12:31 00:32 12:22 00:22 As can be seen the scheme produces fairly mixed results for travel along existing major routes. In the AM period, all three options result in minor decreases in journey time southbound on the M32 and minor increases northbound. The increase in southbound travel times are a consequence of traffic that had previously been queued on the eastbound offslip to M4 J19 being able to complete trips into Bristol on the M32. In the PM period the impact of the scheme is essentially neutral to the M32. Along the Ring Road the scheme produces significant improvements traveling anticlockwise in the AM peak and clockwise in the PM peak. Western Option 1 is notable for the lower reduction in travel time southbound in the PM and an increase in the AM. This is largely a result of the increased traffic on the southern section of the ring road, though Western Option 1 produces the biggest decreases in delays through the Hambrook section of the Ring Road, increases south of the link at Lyde Green offset this when considered travel times along the whole length. For the M4 along the mainline the schemes all result in some inDraftcrease in journey times along the M4 due to the increased traffic induced. Options joining into the M4 further to the west result in larger increases in journey times due to larger increases in traffic between J19 and J20. The changes in travel times for the origin – destination travel pairs are shown in Table 4‐6 and Table 4‐9.

Table 4‐8: Zone to Zone Travel Times AM Peak Hour Origina and Destination Do Western Option 1 Central Option 2 Eastern Option 3A Minimum

Time Time Difference Time Difference Time Difference

St Werburghs to Swindon 40:25 40:26 00:01 40:06 ‐00:19 40:18 ‐00:06

Swindon to St Werburghs 47:22 47:18 ‐00:04 46:51 ‐00:30 47:12 ‐00:10

Filton to Swindon 38:04 38:19 00:15 38:05 00:02 38:17 00:14

Swindon to Filton 46:49 47:28 00:39 46:49 00:00 47:01 00:12

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Table 4‐8: Zone to Zone Travel Times AM Peak Hour Origina and Destination Do Western Option 1 Central Option 2 Eastern Option 3A Minimum

Time Time Difference Time Difference Time Difference

St George to Yate 33:08 32:26 ‐00:42 28:35 ‐01:11 29:26 ‐03:42

Yate to St George 31:59 31:17 ‐00:42 26:37 ‐00:41 28:43 ‐03:17

Kingswood to Yate 31:02 28:04 ‐02:58 25:42 ‐01:32 24:56 ‐06:06

Yate to Kingswood 27:30 27:32 00:02 26:18 01:20 25:35 ‐01:55

Kingswood to Swindon 45:29 42:31 ‐02:58 39:36 ‐05:53 39:23 ‐06:06

Swindon to Kingswood 41:57 41:59 00:02 39:40 ‐02:17 40:02 ‐01:55 Emersons Green to 44:20 39:50 ‐04:31 42:17 ‐02:03 43:09 ‐01:11 Gloucester Gloucester to Emersons 46:27 42:07 ‐04:19 45:07 ‐01:20 45:13 ‐01:14 Green Gloucester to Longwell 57:48 50:56 ‐06:52 49:44 ‐08:04 51:31 ‐06:17 Green M4 – J18 to J21 56:08 52:17 ‐03:51 49:55 ‐06:13 52:29 ‐03:39

Table 4‐9: Zone to Zone Travel Times PM Peak Hour Origina and Destination Do Western Option 1 Central Option 2 Eastern Option 3A Minimum

Time Time Difference Time Difference Time Difference

St Werburghs to Swindon 39:31 40:09 00:38 39:35 00:04 39:42 00:11

Swindon to St Werburghs 39:36 40:26 00:50 39:47 00:11 40:00 00:24

Filton to Swindon 37:58 38:35 00:37 38:08 00:10 38:10 00:12

Swindon to Filton 38:24 39:04 00:40 38:36 00:12 38:46 00:22

St George to Yate 29:36 30:48 01:12 29:08 ‐00:12 28:07 ‐01:29

Yate to St George 27:16 28:05 00:49 25:26 ‐00:28 27:38 00:22

Kingswood to Yate 28:29 26:28 ‐02:02 25:28 00:14 23:46 ‐04:43 29:19 Draft 29:18 ‐00:02 25:44 01:03 25:53 ‐03:26 Yate to Kingswood

Kingswood to Swindon 42:57 40:55 ‐02:02 38:13 ‐04:43 38:13 ‐04:43

Swindon to Kingswood 43:46 43:45 ‐00:02 39:46 ‐04:00 40:20 ‐03:26 Emersons Green to 41:32 40:42 ‐00:49 41:03 ‐00:29 41:11 ‐00:21 Gloucester Gloucester to Emersons 45:58 40:34 ‐05:24 42:30 ‐03:28 44:00 ‐01:58 Green Longwell Green to 52:27 50:20 ‐02:07 48:55 ‐03:32 52:04 ‐00:23 Gloucester Gloucester to Longwell 56:59 52:12 ‐04:47 49:38 ‐07:20 52:17 ‐04:42 Green

In the AM peak there is generally no significant impact on trips two or from parts of Bristol to the north of the M32. In the PM there is a slight increase, as noted with the fixed routes, the further west the option is, the increase is higher due to the induced traffic on the M4. Trips to and from the

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SECTION 4 – STRATEGIC RESULTS East and North East fringes of Bristol generally see significant savings in travel time from the new link. The degree of this generally depends on the option’s proximity, thus Emerson’s Green sees greater savings from the Western Option 1 while Kingswood sees greater savings from Eastern Option 3. Similarly, if the trip is heading to or from Wales or the North Option 1 generally shows greater reductions while trips heading to the East find greater gains from the Eastern Option 3. The slip road only nature of Central Option 2 is noticeable in the additional decrease in travel time for some movements. To and from Yate provides a mixed picture depending on where the trips are heading. Generally, there is an improvement, however trips heading towards Kingswood are finding an increase from the additional delay incurred turning right off the Ring Road junctions. 4.1.4 Movements Using the Proposed Link Select link analysis was undertaken for the two peak periods of the highway traffic using the link in each option. The plots for these are shown in Figure 4‐7 to Figure 4‐12. The purple lines show the volume of traffic on the network that uses the link during its trip while the bar charts show the quantity of trips than start and end at each zone. In this manner, the plots allow both the routes taken and the ultimate origin and destination of the trips using the link to be visualised.

Draft

Figure 4‐7: Selected Link Analysis of Traffic using the Western Option 1 in the AM period.

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Figure 4‐8: Selected Link Analysis of Traffic using the Western Option 1 in the PM period. Draft

Figure 4‐9: Selected Link Analysis of Traffic using the Central Option 2 in the AM period.

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Figure 4‐10: Selected Link Analysis of Traffic using the Central Option 2 in the PM period. Draft

Figure 4‐11: Selected Link Analysis of Traffic using the Eastern Option 3 in the AM period.

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Figure 4‐12: Selected Link Analysis of Traffic using the Eastern Option 3 in the AM period.

As expected the plots show that significant use of the new link is made to or from the eastern fringe of Bristol in addition to south eastern locations, such as Brislington and Knowle, and also from the town of Keynsham. Further, it can be seen that Western Option 1 is relatively more utilised by trips from Emersons Green while the Central and Eastern Options are used by trips from Mangotsfield and Kingswood. That is, the link is generally most accessed by trips starting or ending close to where it joins the A4174. Option 2 also shows very little usage to or from Yate due to the lack of existing Yate link in this option while the Eastern Option 3 shows a greater usage from Yate than Western Option 1. This is likely as, without any improved link to Yate north of the M4, the Eastern Option provides a greater improvement in overall connectivity between Yate and Bristol. Draft A significant difference between the options that can be seen from these plots is use of the link by traffic starting or ending journeys in the northern corner of Bristol (i.e. Patchway & Stoke Gifford etc). The other end of these trips are primarily in the eastern fringe and these trips are using the link to move out to utilise the new J18a to J19 section (as well as J19‐20 and part of the M4) as an outer ring road. This use is most significant in Western Option 1 where use of the link is not a significant detour and lowest in Eastern Option 3 where the extra travel time and distance is less attractive. The use of the link by this movement is the dominant driver behind the much larger increase in traffic on the M4 between J19 and 20 seen in the Western Option. 4.1.5 Transport User Benefits TUBA 1.9.7 was used to provide an indication of the likely transport user benefits of each scheme. Skims of travel time, distance, and monetary tolls incurred along with the trips for all OD pairs for each year, user purpose and time period combination, with and without the scheme, were passed into the TUBA software for each proposed option.

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SECTION 4 – STRATEGIC RESULTS Overall construction costs of the scheme were taken as shown in the following table. These cost estimates were derived by CH2M for the Option Assessment Report. An optimism bias of 44%, typical for a highway scheme at this stage was added.

Table 4‐10: Estimated Scheme Construction Costs Western Route Central Route Eastern Route Series Option 1 Option 2 Option 3a Total incl. development & environment £ 446,081,931.60 £ 520,837,275.81 £ 346,381,163.03 Incl. optimism bias @ 44% £ 642,357,981.51 £ 750,005,677.16 £ 498,788,874.76

The ComMA and SOBC contain assessments made using Highways England Strategic Order of Magnitude Estimate costs.

Draft

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Overall results of the TUBA runs are shown in Table 4‐11 below.

Table 4‐11: Analysis of Monetised Costs and Benefits for Scheme Options Western Option 1 Central Option 2 Eastern Option 3A

Greenhouse Gases ‐29,387 ‐59,073 ‐29,081

Economic Efficiency: Consumer 531,482 735,232 521,337 Users (Commuting & Other)

Economic Efficiency: Consumer 463,485 720,684 496,428 Users (Business)

Wider Public Finances (Indirect 66,394 128,690 62,619 Taxation Revenues)

Present Value of Benefits (PVB) 1,031,974 1,525,534 1,051,303

Broad Transport Budget 490,222 494,478 398,748

Present Value of Costs (PVC) 490,222 494,478 398,748

Overall Impacts

Net Present Value (NPV) 541,752 1,031,056 652,555

Benefit to Cost Ratio (BCR) 2.105 3.085 2.637

All Figures discounted to 2010, in 2010 prices. £000s All options fall into the ‘High’ value for money category, i.e. BCR between 2 and 4, before any Wider Economic Benefits are considered. To obtain a better idea of the spatial distribution of the transport user benefits, the modelled zones have been split into 24 sectors and benefits shown by sector to sector movement in Table 4‐13 to Table 4‐15 below. Figure 4‐13 shows the sectoring system used. Sectors are shown in Figure 4‐13 and described in Table 4‐12.

Table 4‐12: Economics Sectoring System Sector Number DraftLocations Covered 1 Central Bristol 2 Ashton Gate, Southville, Bedminster, Bishopsworth) also including Long Ashton 3 West Bristol (Hotwells, Clifton & Redland) 4 Easton, St Werburgh’s, St Andrews, East Horfield, Lockleaze 5 Totterdown, Knowle, Stockwood 6 Brislington, Hanham, Longwell Green, Warmley and Keynsham 7 St George, Kingswood, Mangotsfield, Emersons Green 8 Downend, Bromley Heath, Frenchay, Broomhill 9 Harry Stoke, Stoke Gifford, East Filton, UWE 10 West Filton, Southmead, Cribbs Causeway 11 Henbury, Shirehampton, Stoke Bishop 12 Lyde Green, Science Park & Folly Brook Rd 13 Patchway & Bradley Stoke 14 Avonmouth, Severn Beach & Thornbury 15 Portisehad, Cleavdon & Nailsea 16 Weston‐Super‐Mare, Dundry & Mendips 17 Bath & South Cotswolds 18 Pucklechurch, Wick

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Table 4‐12: Economics Sectoring System Sector Number Locations Covered 19 Yate, Chipping Sodbury, Winterbourne & Frampton Cotterell 20 The South West 21 The South East & East of England 22 Midlands and The North 23 Wales & Forest of Dean

Figure 4‐13: Sector system for transport user benefit analysis

It can be seen from the following tables that the majority of sector to sector movements have a decrease in travel costs. There are some exceptions. Most obvioDraftus is the movement between 21 and 23 and to a lesser extent, between 20 and 21 and between 22 and 21. The reason for these is largely down to the induced traffic between junction 19 and 20 of the M4 reducing speeds somewhat. Though the increased time for strategic traffic is relatively small, the quantity of trips that incur it results in a reasonable disbenefit. This impact is highest in the western option 1 which induces the most traffic on this section. The second set of movements with a noticeable disbenefit are shorter trips between sectors 6, 7 and 8. This is generally a result of the additional traffic now able access these areas increasing localised congestion. Increased loading on the ring road is also having an impact, despite the junction improvements, however it should be noted that there is a limitation in the modelling regarding this. The standard practice of modelling signalised roundabouts in SATURN (and the method used in GBATS) means that lane use cannot be followed for trips heading for the third (or further) exit on the roundabout. With the junctions converted to hamburgers or signalised cross roads, this limitation does not apply meaning right turns are incurring higher delays even though they would actually have higher capacity.

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SECTION 4 – STRATEGIC RESULTS In terms of benefits the previously discussed differences between the options to the eastern fringe are noticeable in this analysis also. The Western Option 1 shows higher benefits for sector 8 and the science park at sector 12, Eastern Option 3 shows higher benefits for sector 6. Central Option 2 shows generally balanced and high benefits for all eastern fringe sectors.

Draft

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Draft

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