A358 Taunton to Southfields

We’re proposing to upgrade the A358 to dual carriageway between Southfields Roundabout on the A303 and the M5 at Taunton. The delivery of this scheme is part of a long term aim to create a high-quality dual carriage way link between London and the South East and the South West.

Start date TBC
End date TBC
Cost £250 to £500 million

Latest updates

  • 15 July 2021

    Ground investigation surveys

    traffic surveys

    As we develop our plans for the A358 upgrade scheme, some of our teams will be out and about around the route to complete essential surveys of the local area and environment. This includes ground investigation surveys which we use to show all sorts of information – such as buildings, roads, population numbers, height and flooding data. This information helps us to develop our plans for the scheme as carefully and accurately as possible.

    Our teams will also be working on important archaeological surveys. These help to locate historical sites or materials and allow us to make informed decisions about our proposals and the areas where we will look to carry out works in the future.

    Site compound

    As we complete these surveys, some of our teams will be working from a small site in the area. This site compound will be located away from any residential areas and we will make sure that any disruption is kept to a minimum.

    Lane closures

    To carry out the surveys safely, we will be reducing traffic to a single lane on the A358 between Taunton and Southfields roundabout from Monday 26 July to Friday 6 August 2021. These closures will take place on weeknights only, between 8pm and 6am. Because this is a single lane closure, we will not be introducing diversion lanes, only a temporary traffic lights system. 

    If you have any questions or want to speak to a member of our team, please email us at A358@TauntontoSouthfields@highwaysengland.co.uk or call us on 0300 123 5000.

    You can read more about the different types of surveys we'll be doing in the 'Environmental' section further down this webpage.

  • 20 May 2021


    We’ve now awarded a £328 million contract to Taylor Woodrow Plus to design and build the A358 Taunton to Southfields upgrade scheme. We can now update you with what this means for the scheme, what you might see happening along the route and how and when you can have your say on the plans.

    Upcoming closures

    To help us to design the route as best we can, we need to carry out surveys into the current state of the road.

    To carry out these surveys safely we will be introducing a single lane of traffic between Southfields Roundabout and Hatch Green, and an additional one between Hatch Green and Ash Cross from Monday 7 June to Friday 2 July. These closures will take place on weeknights only, between 8pm and 6am. Because this is a single lane closure, we will not be introducing diversion lanes, only a temporary traffic lights system. Emergency access will also be maintained at all times. 

    Environmental surveys

    The countryside along the route is home to some incredible plants and animals - many of which are protected by law - and we need to take steps to avoid them or reduce our impact. That’s why you may see our team out and about carrying out various surveys to look into things like:

    • Air quality
    • Cultural heritage
    • Changes to how the local scenery will look
    • Biodiversity
    • Birds
    • Reptiles
    • Great crested newts
    • Water quality sampling

    With these surveys and design plans well underway, we are continuing to plan for our public consultation, which we expect to take place later this year. Before that, we will be meeting regularly with local community organisations and representatives.

    This will allow us to give updates on the route and to also get important feedback which will help us to shape our final designs. We will be also be speaking to special interest groups, such as walkers, cyclists and horse riders, to make sure that our plans can cater for different road users as much as we can.



  • 27 November 2020

    Early works on the scheme’s preliminary design progressing

    We are pleased to be able to confirm that the A358 scheme has now been allocated to Taylor Woodrow following a competitive tender process through the Regional Delivery Partnerships framework.

    We are now in the process of finalising the scheme contract with Taylor Woodrow, which is scheduled to be awarded early next year. Taylor Woodrow are also progressing early works on the scheme’s preliminary design.

    The scheme is classed as a Nationally Significant Infrastructure Project (NSIP) under the Planning Act 2008. This means we’ll need to make an application for a special type of planning permission called a Development Consent Order (DCO) to gain authorisation to acquire the land and construct the scheme.

    Before we can submit our application for a DCO we will hold a statutory public consultation on the design where we invite comments on our proposals. We are still finalising the future programme for the scheme, but we anticipate holding this consultation in 2021.

    You can find out more about NSIPs on the Planning Inspectorate's website. Alternatively you can watch our short animation which explains the process in simple terms.

  • 24 October 2019

    Preferred route announcement

    Since we announced our preferred route in June, we’ve been carrying out surveys to help inform the scheme design ahead of consultation. In September we held our second Community Liaison Forum and asked the members of the forum to give feedback on the route to help us develop the scheme design. We’ve grouped the feedback given under four headings:

    • local links and community severance
    • process, timeline and scope of works
    • rationale and impact of the route regarding housing development and economic growth with a focus on job creation
    • focus on the location and performance of proposed and existing junctions and access points

    You can see more detail about the feedback in the meeting note in the 'Consultations' folder under the project information section.

    We’ve also been busy creating an animation to explain the process we go through when designing a road scheme such as the A358. We hope this will help you understand the level of detail you can expect to see at each stage.

Project information


The A303/A358 corridor is a vital connection between the South West and London and the South East. While much of the corridor is a dual carriageway, there are still over 35 miles of single carriageway. These sections act as congestion bottlenecks, particularly in the summer months and at weekends, causing delays to road users, and they add to an increased risk of accidents.  

Currently most of the A358 is a single lane and has many local roads and private accesses joining directly with it. It’s often congested and is a source of frustration for local people, and those using the road to travel longer distances.  

Many road users try to avoid the traffic congestion by diverting onto smaller local roads, which then increases the level of traffic in surrounding villages. 

To address this, we’re proposing to upgrade a nine-mile section of the A358 between Southfields Roundabout on the A303 and the M5 at Tauntonto a high quality dual carriageway.  

In 2019 we made our preferred route announcement for the improvement scheme, confirming that we’ll be taking a modified version of the pink option forward. You can find out more about the options consultations and the chosen route.

In delivering the scheme, we’re aiming to:

  • improve the capacity of the road to reduce delays and queues that occur during peak hours and at key times of the year i.e. the height of summer.
  • support economic growth, facilitating growth in jobs and housing by providing a free-flowing and reliable connection between the South East and the South West
  • make the road safer, by providing additional capacity and reducing driver stress. We’ll also improve routes for pedestrians, cyclists, horse riders in the area.
  • protect the environment and look for opportunities to improve it, minimising any unnecessary impact of the scheme on the surrounding natural and historic environment and landscape
  • work with local communities to reduce the impact of the road in terms of community severance, and look for ways to improve local peoples’ quality of life
  • make journey times more reliable and resilient; by providing more capacity it will become easier to manage traffic when incidents occur


Traffic information

Information about scheduled roadworks and events on our motorways and major roads.

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