A350 Melksham bypass
The A350 is one of the most important routes in Wiltshire. It is a primary north-south route with regional significance connecting the south coast with the M4 and onwards to Bristol and the Midlands. In Wiltshire it passes around the principal settlements of Chippenham and Trowbridge via the town of Melksham and neighbouring village of Beanacre, and on to Westbury and Warminster. At Melksham, the A350 serves multiple functions. It is not only the main north-south route through the town, but also the main east-west through route (between A365 Western Way and Bath Road). It also provides access to the town centre and retail developments along the A350 itself for local traffic.
It has been a longstanding priority for the council to improve north-south connectivity along the A350, but to also recognise the important local function that the existing route serves at Melksham, and issues such as journey time delays and poor reliability, accidents, severance and noise and air quality.
This page contains background information about this project, which will be updated as progress is made and as further information becomes available.
Watch a video fly through of the emerging route
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After seeking the views of residents, businesses and other stakeholders on a variety of options in late 2020 early 2021, the scheme was worked up in more detail and we asked again for views on the emerging route option during summer 2021. Following the conclusion of the second stage non-statutory consultation, we developed and published the consultation report.
A350 Melksham Bypass - Second Public Consultation Report
The findings of that second stage non-statutory consultation were reported to Wiltshire Council's Cabinet meeting in November 2021, Cabinet considered the response and how to move forward. Cabinet noted the response to the second consultation and indicated that potential route variants emerging through the consultation response should be subject to further investigation and consultation.
Agenda and minutes - Wiltshire Council Cabinet - Tuesday 30 November
An update presentation on the scheme progress was subsequently provided to Melksham Area Board in December 2021. A copy of the presentation slides from that presentation can be found here:
Melksham Area Board Presentation - December 2021 (PDF) [1MB] (opens new window)
National Highways are currently undertaking a strategic North-South connectivity review. Their study encompasses the Wiltshire geographic area and includes the A350 as a key route. The outcomes of that study may have implications for the status of the A350, and the outcome of the National Highways works will need to be considered as the scheme develops.
Most recently, various draft documents have been submitted to DfT in connection with the OBC for consideration. Copies of the draft OBC submission documents are available through the FAQs below. These will be supplemented and updated as the scheme progresses in line with Cabinet resolutions.
The first consultation sought views on a wide range of options for the scheme. Following further assessment work and having considered the response to the first consultation, an emerging route was identified and developed further.
The second consultation focussed on that emerging route and the three options regarding how the scheme would connect to the A350 at its northern end.
Public consultation November 2020 - January 2021.
Between November 2020 and January 2021, we undertook an initial consultation exercise regarding the potential improvements. We received more than 1,000 questionnaire responses, and 175 additional written submissions.
Download the full consultation report A350 Melksham bypass consultation report (PDF) [744KB] (opens new window) .
Download the consultation report appendices A350 Melksham bypass consultation report appendices (PDF) [907KB] (opens new window) .
- Melksham Bypass Consultation Information Pack (PDF) [3MB] (opens new window)
- Melksham Bypass information on Options 7 to 10 (PDF) [7MB] (opens new window)
- Consultation launch presentation A350 - Melksham Area Board 4 November 2020 (PDF) [1MB] (opens new window)
- A350 Melksham Bypass Strategic Outline Business Case 2017 (PDF) [1MB] (opens new window)
- A350 Melksham Bypass Strategic Outline Business Case 2017 Appendices (PDF) [5MB] (opens new window)
A350 Melksham Bypass Strategic Outline Business Case 2019 Addendum Full (PDF) [12MB] (opens new window)
Public Consultation June - August 2021.
Between June and August 2021, we undertook a second public consultation regarding the potential improvements. We received 760 questionnaire responses and 480 additional written submissions.
- Melksham Bypass 2nd Consultation Information Pack - June 2021 (PDF) [3MB] (opens new window)
- Emerging Bypass Option - June 2021 (PDF) [6MB] (opens new window)
- Melksham bypass Options Assessment Report (OAR) Draft - May 2021 - Part 1 (PDF) [21MB] (opens new window)
- Melksham bypass Options Assessment Report (OAR) Draft - May 2021 - Part 2 (PDF) [12MB] (opens new window)
- Options Assessment Report (OAR) Draft - May 2021 - Appendices (PDF) [21MB] (opens new window)
- Melksham bypass Walking Cycling Horse Riding Assessment (WCHAR) - June 2021 (PDF) [14MB] (opens new window)
- Melksham Area Board 2nd Consultation Launch Presentation - June 2021 (PDF) [2MB] (opens new window)
- Melksham bypass webinars July 2021 Q&As (PDF) [328KB] (opens new window)
The first consultation exercise undertaken between November 2020 and January 2021 provided useful information, comments and ideas that have fed into the scheme development and options assessment work. As well as raising awareness about the project and promoting engagement with stakeholders, the first consultation highlighted matters such as:
- The importance held by the local community with regards to access to the countryside
- Alternative route suggestions, which have been considered
- Various ideas and initiatives regarding potential walking and cycling measures
- Potential severance affect that some alternative route options may have generated
- Valuable information regarding the overall support for improvement works to the A350 corridor at Melksham.
The second consultation exercise undertaken between 23 June and 8 August 2021 also provided useful information, comments and ideas that will feed into the future scheme development. As well as raising awareness about the project and promoting engagement with stakeholders, the second consultation highlighted matters such as:
- The divergence of opinion between those who supported the need for an improvement to the A350 and those who did not
- Concerns regarding potential impacts on the countryside habitats and the environment
- Concerns regarding noise impacts and air quality impacts
- Concerns regarding impacts on wildlife
- The importance held by the local community with regards to access to the countryside and impacts regarding physical and mental well-being
- Alternative route suggestions, which will be considered
The consultation report detailing the outcome of the second consultation can be accessed online - A350 Melksham Bypass - Second Public Consultation Report.
We undertook an assessment of the route options, taking into account the results of the previous public consultation, and reviewed the route options against the scheme objectives. Option 10c was identified as the most viable route, although there are alternative alignments at the northern end, which are being consulted on.
Other potential options were discounted for a range of reasons as the scheme has evolved, including not addressing the scheme objectives, design constraints, costs leading to limited value for money, technical deliverability, local impacts, and environmental matters. It is important that the scheme progressing through to the outline business case represents the best identified solution possible.
If any of the other options had scored as well as Option 10c against the criteria, they would have been included in the second round of consultations.
The second engagement exercise has now ended.
Further consultations will take place and opportunities will be provided to help shape the project at Planning Application stage. Further details will be advertised through news items and via the local media, and this page will be updated as the scheme develops.
The A350 is one of the most important routes within Wiltshire, connecting several of our principal settlements. It has been a longstanding priority for the council to improve north-south connectivity via the A350, and through alternative travel methods such as rail. This reflects the significant role of the A350 corridor in supporting economic activity and growth. The corridor has accounted for approximately 60% of all housing growth in Wiltshire over the last 15 years.
In recent years, we have been successful in attracting funding for the delivery of various improvements to the A350, such as upgrades to sections of the A350 around Chippenham, improvements at M4 Junction 17, and capacity enhancements at Farmers Roundabout, Melksham, which was completed in October 2019.
The A350 is also of wider regional significance, providing north-south connections between the south coast (the port of Poole in particular) and M4, and onwards to Bristol and the Midlands.
The scheme was one of nine priority schemes identified by the Western Gateway Sub-national Transport Body. Find out more.
In March 2020, the Government awarded funding to further develop the case for the A350 Melksham bypass, having considered our initial submission made in July 2019. We are now undertaking technical exercises to enhance the evidence base for this bypass, and this work will inform an updated business case submission to government in autumn 2021.
Improvements to the A350 at Melksham have been considered for many years. Recent funding made available by Government has made it possible to put forward a proposal for a scheme of the scale and nature required to address the transport issues in a comprehensive manner.
The scheme is being promoted through the Department for Transport's Large Local Majors Fund - specifically intended to support a small number of exceptionally large local highway authority road schemes that could not be funded through normal routes.
The A350 at Melksham serves multiple functions. It is not only the main north-south route through the town, but also the main east-west through route (between A365 Western Way and Bath Road). It also provides access to the town centre and retail developments along the A350 itself for local traffic.
Traffic flows are high - approximately 35,000 vehicles daily (Annual Average Daily Flow). Heavy Goods Vehicles (HGVs) account for approximately 7% to 9% of traffic.
Based on survey data collected in 2017, approximately 40% of all traffic entering or leaving Melksham on the A350 via Beanacre is through-traffic, with the remaining 60% starting or ending its journey in Melksham. Of the 40% through-traffic, approximately 25% are north-south movements.
In October 2019 the Council completed a localised capacity enhancement at Farmers Roundabout on the A350 at Melksham. This has improved traffic flow at this location, but limitations with other sections of the route, and the prospect of further housing development and traffic growth in the corridor, requires consideration of a comprehensive, strategic solution to this section of the A350.
The key issues that need to be addressed (now and for the future) include:
- Journey time delays and poor reliability
- Noise and air quality
You can find out more about these issues in the downloadable PDFs on this page.
Any major road scheme takes a long time to develop and follows a statutory process that is used to create a robust business case. You can see the steps of the process below. The Melksham bypass project is currently at step 8.
- Establish a need for a scheme
This can be due to either known congestion problems or identified from routine forecasting of future traffic growth on the UK road network.
- Establish the initial strength of case for a new road scheme
This is undertaken by modelling the current road layout using present day traffic flow data and identifying the location and causes of congestion.
- Identify a long list of scheme options
These can range from improving access to public transport, restrictions to traffic flow, to junction improvements, road widening and dualling to entirely new road schemes. This will involve high level design to establish length of road, number of crossing structures and the likely construction costs.
- Options assessment (assess the viability of route options)
This will involve several areas of assessment which would be used to quantify the benefits of on a comparative scoring system. These areas of assessment are summarised as follows:
- Modelling the proposed options (road or otherwise) to establish whether the improvements in journey time they bring, expressed in economic terms exceed their delivery cost;
- Undertake a desk-based assessment of ecological receptors close to each proposed route to determine any adverse impacts the scheme may have in environmental terms;
- Establish potential conflicts or benefit on landscape visual impact presented by the scheme, along with impacts on existing property and conflicts with committed development. This would also consider the likely impacts on quality of life for local residents that the scheme may bring, including opportunities for greater accessibility for pedestrians and cyclists;
- Assess the flood risks against the new route footprints, through use of available flood data
- Desk based assessment of potential archaeological impacts from the proposed options, and
- Assess geographic and geological constraints, including contaminated land.
- Public engagement on long list options
Once the long list of options has been identified and the technical and environmental constraints identified, the assessment process will move on to public engagement. This process provides an opportunity to present the proposed scheme in an informed manner and to describe the type of options under consideration, and on the impact they are likely to have on the local community. Views and feedback will be sought from the public at public engagement events.
- Identification of Short list Options
The assessment of the viability of route options will conclude with the short listing of the most viable routes based on cost effectiveness (highest benefit cost ratio) and the greatest overall benefit and least adverse impact to the natural environment and the community. The design of the short-listed options will then be developed to more detail, using topographic and ecological walkover surveys to confirm the most appropriate alignment. Traffic modelling will refine the junction locations and layouts and will then be used to establish impacts on air quality and noise.
The environmental information gathered will then be assessed and the findings presented as part of a dedicated environmental report, the Preliminary Environmental Assessment Report. Feedback from public consultation will also inform route option refinement and how selection is assessed.
Together, this will ensure the shortlisted options are properly assessed in terms of their viability.
The findings of the assessment process will then be presented as part of a further public engagement as part of the public consultation expected of Outline business case process.
- Public engagement on shortlist options
The public will be presented with the shortlisted options at a further consultation event, where the benefits and disadvantages of each will be discussed. Public feedback will again be sought and will be used to inform the identification of the preferred scheme option.
- Outline Business Case (OBC)
An Outline Business Case (OBC) will be prepared that captures the findings of the overall assessment and option selection process. This is a document that will set out the justification of a scheme, presenting its cost to deliver and the benefits it will deliver to the community and the local and national economies. The OBC is broadly divided across five chapters, each capturing the assessment work as part of a distinct topic paper or chapter:
- Strategic Case
- Financial Case
- Economic Case
- Management Case
- Commercial Case
The Outline Business Case will be submitted to the Department for Transport (DfT) with supporting information as an application for scheme approval. DfT will then assess the scope and content of each of the OBC chapters to ensure they have been considered in sufficient detail to be compliant with DfT's reporting requirements. This assessment will include DfT reviewing the Transport models and the detail of the supporting evidence. The OBC will also be reviewed against the feedback received from the public consultation exercise to ensure the views of the local community have been properly considered and that the case put forward for the scheme stands up to scrutiny.
If DfT is satisfied that the design of the preferred route option is sufficiently robust and the assessment work has been carried out to an acceptable standard, then it will grant approval for government funding for the next stage of the scheme, which is formal design of the road and preparation of a planning application.
The transport objectives of the scheme were agreed by the council's Cabinet on 13 October 2020 and are to:
(i) Reduce journey times and delays and improve journey reliability on the A350 through Melksham and Beanacre, improving local and regional north-south connectivity, and supporting future housing and employment growth in the A350 corridor.
(ii) Reduce journey times and delays on and improve journey reliability on the following routes through Melksham and Beanacre:
- A350 South - A3102
- A365 West - A365 East
- A350 South - A365 West
(iii) Provide enhanced opportunities for walking and cycling between Melksham town centre and the rail station / Bath Road, and along the existing A350 corridor within Melksham and Beanacre, which will help reduce the impact of transport on the environment and support local economic activity.
(iv) Reduce personal injury accident rates and severity for the A350 and Melksham as a whole, to make the corridor safer and more resilient.
(v) Reduce the volume of traffic, including HGVs, passing along the current A350 route in northern Melksham and Beanacre to reduce severance, whilst avoiding negative impacts on other existing or potential residential areas.
There is the potential to deliver many strategic benefits including:
- Creating a more reliable, less congested, and better-connected transport network that works for the users who rely on it.
- Providing a well-connected, reliable and resilient transport system to support economic and planned development growth at key locations.
- Supporting and helping to improve the vitality, viability and resilience of Wiltshire's economy and market towns.
- Providing transport infrastructure to support new housing in the western Wiltshire corridor.
- Assisting the efficient and sustainable distribution of freight in Wiltshire to build stronger, more balanced economy by enhancing productivity and responding to local growth priorities.
- Supporting and promoting a choice of sustainable transport alternatives.
- Reducing the level of air pollutant and climate change emissions from transport.
- Improving safety for all road users and reducing the number of casualties on Wiltshire's roads.
The local benefits are likely to include:
- Improving access to the railway station from the town and residential areas.
- Improving walking and cycling routes from the town to the south and Semington.
- Improving air quality and reduced traffic noise on existing A350 through Beanacre and Melksham.
- Improving access to local services, shops, amenities and schools with the removal of through traffic.
- Reducing severance impacts on communities in Beanacre and northern Melksham caused by high traffic volumes.
- Creating opportunities for town centre regeneration.
The Strategic Outline Business Case (SOBC) established the strategic need for the scheme. The proposals are now being developed in more detail to identify a preferred option. The information in the SOBC will be updated in the Outline Business Case currently being developed.
A wide range of options were initially considered for the scheme, including non-road and bypass options. These were the subject of a public consultation between November 2020 and January 2021, and there is further information on those in the legacy documents section. They included routes to the west and to the east of the town, as well as improvements to the existing road and public transport, walking and cycling options.
Following the consultation, the options were the subject of a sifting process to identify those which would meet the scheme objectives. This process and its results are described in the Options Assessment Report (OAR) included with the latest consultation material.
The possibility of a route south of the canal was suggested at the Melksham Area Board in March 2020, and it was considered appropriate to consider this option at an early stage as it had been suggested. It is important that all options are considered in identifying a preferred option. Following further investigation this route has now been discarded.
Yes. A large number of comments were received and considered following the first consultation, with changes made to the proposals in response to the suggestions and comments.
The A350 is a regionally important north-south route which needs to have adequate traffic capacity to accommodate anticipated future growth in western Wiltshire.
Dualling the existing route south of Farmers Roundabout would be possible, but improvements to the existing road through Beanacre and at the northern end of Melksham to the standards required to meet the needs of the major road network would have extensive adverse impacts on the built up area.
Without the northern section also being improved there would remain a constraint on traffic flows and speeds on the route, with the environmental and safety problems remaining and worsening over time. Improving the existing route was not considered to be a viable means of achieving the transport objectives.
Western routes have been considered but would generally require structures for rail, road and floodplain crossings which would result in adverse landscape and visual impacts due to the scale and height of the structures required.
Some of the western options would perform similarly to the eastern route but would have a higher cost and greater technical and environmental risk. The longer western route would also present a number of delivery complexities with a higher cost.
The western route options had less public support than the eastern routes, and on balance it was not considered appropriate to take them forward to the next stage of consultation.
Shorter eastern routes connecting to the existing Eastern Way distributor road performed moderately well against the primary scheme objectives. They would have a lower cost than the longer routes and have less effect on the landscape.
Whilst the longer eastern routes would be more expensive, they would have greater benefit to cost ratios when assessed using the DfT methodology and would be more likely to attract funding. The assessment indicates that the economic case for the shorter options would be marginal.
The public consultation response indicated concerns about severance of the walking and cycling routes between the town and the school with the shorter eastern routes. The use of Eastern Way local distributor road as part of the major road network was also a concern to residents.
In view of the outcome of the sifting exercise and taking the public consultation response into consideration it was not proposed to progress further the development of the short eastern bypass options.
The consultation and recent assessment work considered all options, and they were reviewed on the same basis. There was no preference for any of the options as it is important to identify the most suitable option that would meet the objectives and be likely to obtain funding.
It is appreciated that there has been discussion about a potential eastern bypass of Melksham since at least the 1990s. The Strategic Outline Business Case prepared in 2019 identified a potentially viable long eastern route, and the viability of the route corridor has been confirmed by the options appraisal work carried out since.
If any of the other options had scored as well as Option 10c against the criteria, they would have been included in the second round of consultations.
There was considerable support for walking, cycling and public transport improvements in the response to the first public consultation. However, the options sifting process concluded that improvements to walking and cycling and public transport were unlikely to meet the objectives in themselves but could complement other options and should be progressed in conjunction with the scheme.
The current consultation material includes complementary measures in connection with walking and cycling which are being developed in parallel with the bypass scheme. These could be implemented as part of the scheme or could be delivered separately through other funding sources should opportunities arise.
As well as reducing journey times and delays, the scheme would provide significant opportunities for enhanced walking and cycling between Melksham town centre and the railway station and other parts of the town. Indeed, the provision of a bypass would be expected to help reduce traffic flows along the existing A350 corridor and in the town centre itself, and through this allow for a more pleasant and connected environment with opportunity for walking and cycling improvements.
A preferred route is emerging from the work thus far undertaken, but this will need further development as the scheme progresses. It is anticipated that the route will be better defined during the next phase of design, but it should be noted that the scheme will be the subject of a planning application and probably a public inquiry and consequently there may be some changes as a result.
If approved, and depending on the details of the final scheme the construction costs are expected to be in the region of £146 million (based on 2019 prices), and there would be contingency and inflation costs. The Business case will consider the total cost of the scheme and the potential benefits to determine whether it would offer value for money in economic terms.
Wiltshire Council would not be able to fund a scheme of this type from its own resources. It would be necessary to bid for funding from the Department of Transport (DfT) and to make the case for the scheme by preparing a business case which would include the cost and economic benefits. The decision regarding funding for the scheme would be made by the DfT after considering the business case.
No. Funding contributions from developers have not been identified at this stage. Any planning applications by others will be considered on their merits in accordance with the regulations and relevant guidance and policy. The policy position at present reflects the adopted Core Strategy and this is being reviewed and will result in a revised Local Plan scheduled to be adopted before commencement of works on site to deliver the scheme.
Through development of the Local Plan, a transport evidence base will be produced, and this will propose mitigation measures to support housing development being brought forward. Should the evidence base provide a direct linkage between housing delivery and the need for Wiltshire's A350 improvement schemes, such as the bypass, then Local Plan policy may reflect this and provide material support for the collection of contributions towards the cost of the scheme.
The consultation is not a public 'vote' for the most popular route or option. There are many factors to be taken into account in determining the preferred scheme, including, landscape, archaeology, ecology, air quality, flood risk, environment, cost and benefits. The final route may be a variant of the route currently being consulted on as the design could be refined in response to the consultation.
Yes. The scheme is still at a very early stage. Further consultation will take place, especially in connection with the planning application and any statutory orders required for the scheme after the proposals have been developed in more detail.
No. The cost of the options is taken into account in considering the economic case, but a more expensive option may deliver better benefits in terms of reduced vehicle operating costs and improved road safety than a cheaper one. The environmental factors are also important considerations in determining a preferred route.
New purpose-built roads and bridges generally do not have the maintenance problems associated with the older roads that have evolved over the years and were never envisaged to carry the volume and types of traffic now using them. Maintenance costs are taken into account in assessing route options but are not usually a major consideration compared to the other factors.
Yes. The cost of bridges and underpasses required for rivers, watercourses, minor roads and public rights of way are included in the cost estimates.
Yes. Construction costs were prepared and compared for each of the route options on the same basis, including allowances for the costs of bridges and other associated works such as drainage, signs and lining. At this stage factors are applied to represent the risks and unknowns associated with the scheme, and design and development costs are included. As the scheme progresses the cost estimates will be refined and the economic case for the scheme reviewed.
The option costs are estimated on the same basis using a common price base. These can then be adjusted according to the latest predictions of inflation for future years, when the expenditure is likely to be incurred. The scheme benefits are likely to arise over a significant number of years in the future, and these too are discounted back to a common base year in order to derive a cost benefit ratio for the scheme. The factors and allowances for inflation are updated by the Department for Transport from time to time as additional information becomes available.
Generally, the cost of previous schemes, or works already completed and paid for, are not considered in the cost benefit analysis as these are considered to be sunk costs. The business case looks at the costs still to be incurred and the benefits likely to arise in the future.
The options are assessed in accordance with the Department of Transport's Transport Analysis Guidance (TAG). This methodology and guidance are the standard approach to assessing major transport schemes of this type, and the information is regularly updated by DfT.
There is no predetermined formula to weight scores because different environmental factors may not be directly comparable with each other, or with economic and road safety aspects. The intention is to build up a framework of the individual assessments in order to get an overview to assist option selection. The options have also been assessed against the objectives for the scheme.
Yes. When the scheme has been designed in more detail, including mitigation measures, a full environmental impact assessment will be undertaken as part of the planning application for the scheme.
A Preliminary Environmental Assessment Report (PEAR) has been undertaken to provide early information on the environmental impacts and consequential effects of the Scheme. The documents can be found below.
Melksham Bypass PEAR Volume 1 - Main Report (PDF) [3MB] (opens new window)
Melksham Bypass PEAR Volume 2 - Appendices (PDF) [13MB] (opens new window)
Melksham Bypass PEAR Volume 3 - Figures (PDF) [96MB] (opens new window)
Melksham Bypass PEAR Volume 3 - Figures Part 1 (PDF) [28MB] (opens new window)
Melksham Bypass PEAR Volume 3 - Figures Part 2 (PDF) [25MB] (opens new window)
Melksham Bypass PEAR Volume 3 - Figures Part 3 (PDF) [21MB] (opens new window)
Melksham Bypass PEAR Volume 3 - Figures Part 4 (PDF) [20MB] (opens new window)
The impact of the scheme would be considered in the light of emerging policies and strategies at Government and local level. The reduced traffic congestion, better facilities for active travel, and improved road safety would be expected to reduce energy consumption as a result of the scheme. This will be assessed as part of the scheme appraisal process. There would be scope for the use of energy efficient plant, materials and processes to reduce the carbon footprint of the construction stage of the scheme.
The potential effects of climate change will be taken into account in the design of the scheme. This would include making allowances for increased rainfall and flood risk, as well as the use of more durable materials to provide resilience in connection with increased temperatures and other impacts of climate change.
The potential impacts on the landscape and the countryside will be assessed as part of the scheme assessment process, and various mitigation measures would be considered. The development of the scheme will include a package of landscaping proposals to help mitigate the impact on the landscape.
The business case for the scheme will need to consider a range of traffic growth scenarios for both high and low growth. It is anticipated that the Government will revise future traffic and economic growth figures in view of recent events, and the scheme will be assessed on the basis of any revised Government predictions.
The scheme has the potential to improve road safety and reduce the number killed and seriously injured on our roads. The removal of through traffic from residential areas could reduce traffic noise and air pollution with consequent health benefits for residents, but some of the options could also have the potential to introduce traffic into previously unaffected areas and may have other detrimental effects. The scheme assessment and business case for the scheme will take these impacts into consideration.
A Wiltshire Traffic Model has been created which covers the wide area of the county. This computer model makes use of a large number of traffic counts across the highway network. It is not just based on traffic counts in the Melksham area. This allows schemes and proposals across the county to be modelled with a high degree of accuracy, and enables the computer modelling of combinations of road and development proposals to be assessed. Having robust data to inform options appraisal is an important part of the scheme assessment process.
There are Major Road Network schemes on the A350 at M4 Junction 17 and Chippenham Bypass Phases 4 and 5, which would be included in the traffic modelling, as well as consideration of potential schemes in connection with development such as Future Chippenham and the Yarnbrook to West Ashton Relief Road. Various scenarios may need to be modelled in view of the uncertainties connected with some of these schemes.
The scheme is being prepared in accordance with Department for Transport (DfT) guidance, and the traffic model is validated and checked using separate traffic counts. The traffic modelling will be reviewed by DfT during the development of the scheme to ensure that the modelling and economic assessments are robust. The business case for the scheme will be assessed by experts at the DfT before funding for the scheme is awarded.
The emerging Local Plan is expected to result in proposals for additional housing in the county in order to meet Government targets. The nature and location of this will be determined by the Local Plan process, which will use a similar traffic model to the scheme to ensure consistency. The traffic modelling for the Melksham Bypass will be rerun and reviewed as further information on growth and future traffic movements becomes available.
Induced traffic can occur when there is a suppressed travel demand, especially because of severe congestion on a network. This can result in an additional increase in traffic. This is not usually a major factor in Wiltshire because in most places the level of congestion is not as severe as in many predominantly urban areas. However, the traffic modelling being carried out will consider this aspect, including taking into account other improvements on the network. On the A350 the main factor influencing traffic growth on the network is expected to be from population growth, particularly in connection with housing and employment expansion in the corridor.
Average daily traffic flows on the bypass in 2036 are predicted to be between 22,000 and 27,000 vehicles with over 1,400 being heavy goods vehicles. Indicative changes in traffic flows are shown in the consultation document.
The provision of a good quality road is likely to attract some local traffic movements to make use of the bypass rather than use less suitable minor roads. The potential changes will be examined in more detail as the scheme is developed.
A junction where the route crosses Woodrow Road was investigated but it was considered that this could attract traffic from the town to use that local road to access the bypass with consequent traffic increases on a road which would be unsuitable for high traffic flows.
It is likely to be a single carriageway, but it is likely that provision for future dualling would be included where justified, as has been the case with other schemes on the A350 in Wiltshire.
It is anticipated that the route would be designed as far as possible to the national speed limit, which is currently 60mph for a single carriageway. It would be designed to current Department for Transport standards for a road of this type, and it is expected that consideration would be given to the changes necessary to convert it to a dual carriageway in the future if necessary.
It is likely that the junctions would be roundabouts. It is unlikely that the use of grade separated junctions with slip roads would be justified with the currently anticipated traffic flows on the main route and the side roads.
Where routes cross footpaths and rights of way, arrangements would be made to provide crossing facilities where practicable, which could include bridges or underpasses. In some cases, rights of way may be diverted to safe crossing points at agricultural or accommodation overbridges or underpasses. The amenity value of rights of way is appreciated, especially those close to urban areas, and as far as possible the severance of routes would be avoided. Pedestrian, equestrian and cyclist crossing facilities could also be provided at junctions where traffic speeds would be lower.
It is unlikely that a cycle route would be provided alongside the bypass, but cycle routes could be provided to link existing routes, and facilities could be included along the bypassed road, linking to a wider network of routes within the town. Proposals for cycling improvements in the town are being developed in parallel with the proposed scheme.
The scheme would potentially sever farm holdings and affect agricultural operations. Refinement of the scheme, including minor changes to the alignment, could reduce these impacts, and the provision of bridges or underpasses, especially if also used by rights of way could also help, but where this is not feasible it may have to be treated as a compensation matter. Direct access onto the bypass from fields and properties would be generally be avoided for safety reasons. The current consultation is seeking to obtain further information on land use in order to understand how potential impacts could be reduced.
The potential Wilts and Berks canal was shown as one of the potential route constraints on the initial consultation information. As both schemes develop the exact arrangements for accommodating the the canal will become more clear. The current bypass proposals include the provision of a bridge over the route of the old canal.
It would be expected that major junctions and roundabouts would have street lighting for safety reasons. The majority of the route would be unlikely to be lit.
Landscaping and planting would be included in the scheme where it would help to reduce the visual impact. The exact arrangements would be determined as part of the detailed design, taking into account the local environment and landscape. The creation of ponds and wildlife habitats would also be included in the proposals where there are opportunities for enhancement.
The scheme assessment in connection with the Outline Business Case will consider the environmental aspects of the proposals and any potential mitigation measures. The current consultations and information being collected, will help inform the design of the proposals to reduce the impact of the scheme.
Yes. Information on the known archaeology in the area is being used to inform options appraisal. As the scheme develops more specialist investigations and surveys may need to be carried out. This could include excavations and other survey methods in order to get a full understanding of appropriate measures required in connection with the scheme. Specialist advice is being sought in connection with the proposals.
There are clearly some air quality issues in connection with the existing road. The effects on traffic flows and air quality as a result of the scheme will be considered and will form part of the assessment in the Outline Business Case.
The removal of through traffic from existing roads would reduce traffic noise for nearby properties, but it could increase traffic noise for other properties or introduce traffic noise into currently comparatively quiet areas of countryside. The scheme assessment process will include consideration of these potential impacts.
Any river or watercourse crossings would need to be designed so as not to increase flood risk and would include an allowance for predicted climate change. The drainage arrangements for the scheme would have to consider flood risk as well as water quality. It is likely that substantial bridges would be required at river crossings and where the routes crosses floodplains.
A full drainage scheme would be developed, which would include consideration of water quality and treatment. Often soakaways are the preferred means of disposing of surface water, but these are unlikely to be feasible in this area. It is expected that the water would be collected by pipes and ditches, and then directed to holding ponds to limit the flow into watercourse or rivers, and to provide the opportunity to remove silt and pollutants. The design of outfalls from drainage systems would take into account the ecological value of the receiving watercourses.
Some walk over surveys and associated work have already been undertaken to inform options assessment, but these form only a small part of the extensive investigation and assessment work which needs to be carried out for a scheme of this type. Specialist ecological, environmental, archaeological, ground investigation and topographical surveys will be carried out as part of the detailed design.
Once the scheme has planning permission, negotiations will be entered in to with affected land owners to agree terms for the purchase of the necessary land. If required a Compulsory Purchase Order may be used, which could result in a Public Inquiry where an Independent Inspector would consider the evidence and make a recommendation to the secretary of State regarding the orders.
The construction of the scheme will depend on the successful completion of the statutory procedures. It is currently anticipated that construction would start in 2026, with the scheme opening in 2028.
It is hoped to bid for funds to improve the A350 at Westbury, but this scheme will fall into a further round of government funding, which is unlikely to begin until 2025.
Yes. The Outline Business Case, which is currently being developed, and the supporting documentation will be available to the public. The following draft OBC documents have been submitted to DfT:-
A350 Melksham Bypass - Outline Business Case (PDF) [19MB] (opens new window)
Appendix A2 - Options Assessment Report (PDF) [55MB] (opens new window)
Appendix A3.1 - Emerging Route Option (PDF) [3MB] (opens new window)
Appendix A3.2 - Emerging Route (PDF) [5MB] (opens new window)
Appendix A3.3 - Emerging Route Long Section (PDF) [324KB] (opens new window)
Appendix A3.4 - Emerging Route showing proposals at Public Rights of Way (PDF) [5MB] (opens new window)
Appendix A3.5 - Emerging Route and Alternative Route Options (PDF) [10MB] (opens new window)
Appendix A4 - M4 to Dorset Coast Connectivity Study (PDF) [5MB] (opens new window)
Appendix B1 - Local Model Validation Report (PDF) [11MB] (opens new window)
Appendix B2 - Model Forecasting Report (PDF) [12MB] (opens new window)
Appendix B3 - Appraisal Specification Report (PDF) [3MB] (opens new window)
Appendix B4 - Appraisal Summary Table (PDF) [91KB] (opens new window)
Appendix B5 - Economic Appraisal Report (PDF) [7MB] (opens new window)
Appendix B6.1 - Transport Economic Efficiency (PDF) [87KB] (opens new window)
Appendix B6.2 - Analysis of Monetised Costs and Benefits (PDF) [72KB] (opens new window)
Appendix B6.3 - Public Accounts (PDF) [66KB] (opens new window)
Appendix B7 - Appraisal Cost Proforma* (PDF) [82KB] (opens new window)
Appendix B8 - Social and Distributional Impacts Appraisal (PDF) [5MB] (opens new window)
Appendix B9.1 - Air Quality Impacts* (PDF) [82KB] (opens new window)
Appendix B9.2 - Noise Impacts* (PDF) [74KB] (opens new window)
Appendix B9.3 - Biodiversity Impacts (PDF) [94KB] (opens new window)
Appendix B9.4 - Water Environment Impacts* (PDF) [148KB] (opens new window)
Appendix B9.5 - Landscape Impacts (PDF) [83KB] (opens new window)
Appendix B9.6 - Historic Environment Impacts (PDF) [74KB] (opens new window)
Appendix B10 - Alternative Carbon Emission Assessment (PDF) [111KB] (opens new window)
Appendix C1 - Quantitative Cost Risk Analysis (PDF) [191KB] (opens new window)
Appendix D1 - Procurement Strategy (PDF) [968KB] (opens new window)
Appendix E1 - Organisation Chart (PDF) [720KB] (opens new window)
Appendix E2 - Full A350 Melksham Bypass Programme (PDF) [2MB] (opens new window)
Appendix E3 - Stakeholder Engagement and Communications Plan (PDF) [207KB] (opens new window)
Appendix E4 - Risk Management Plan (PDF) [615KB] (opens new window)
Appendix E5 - Risk Register* (PDF) [148KB] (opens new window)
Appendix E6 - Benefits Realisation, Monitoring and Evaluation Plan (PDF) [3MB] (opens new window)
Appendix E7 - Planning Strategy (PDF) [2MB] (opens new window)
Appendix E8 - Carbon Management Plan (PDF) [874KB] (opens new window)
*These documents are a summary only, the contents of which have been developed by further documentation.
Yes. There will be a planning application following the submission of the Outline Business Case should the scheme proceed. This would include full details of the proposed scheme with supporting information. The scheme would be the subject of statutory consultation at the planning application stage.
It is likely that a scheme of this type would require a Compulsory Purchase Order and other statutory orders, which could result in a Public Inquiry. An Independent Inspector would then make a report to the Secretary of State for a decision.