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

  • 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


    We’re carrying on with our surveys that will help inform our future scheme design. We’d like to thank everyone who has been affected by our surveys for their patience and understanding, it’s really appreciated.

    We’re also carrying out a procurement exercise to appoint a new designer to take the scheme forward through the statutory phase and into construction. It’s anticipated we’ll finish this exercise in 2020. We’ll hold the next Community Liaison Forum once the new designer is on board.

  • 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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