A350 Chippenham Bypass Dualling

Scheme outline

Upgrade of the existing single two-lane A350 Chippenham Bypass to dual two-lane standard from its northern terminus to the junction with the A4, being constructed progressively in a series of short upgrades. The widened road will link in with the recently improved dual carriageway from Chippenham to the M4.

Work has already been completed in the middle part of the bypass around Brook Roundabout and work is progressing to the north and south.

In time, Wiltshire Council plan to widen and improve the entire bypass from Lackham to the M4 to the same standard.

Under construction
Other upgrade
for use by all traffic
Highway authority
Wiltshire Council and Swindon and Wiltshire Local Enterprise Partnership


5 October 2016

The section either side of the Bumpers Farm is now complete. There are outline plans to complete the remaining sections in 2017, with various options being presented.

3 July 2017

Work commences July 2017 to dual the half-mile section from the Brook roundabout to the Badger roundabout, making the entire run from the Bumpers Farm roundabout to M4 J17 dual carriageway. Then work starts to dual 250m either side of the Chequers and Cepen Park South roundabouts and the short section between them, also adding an extra lane on the A4 either side of its approach to the Chequers roundabout. This will leave the section between the Cepen Park South and Bumpers Farm roundabouts single carriageway, with this to be addressed at a future date.

Further information: http://www.wiltshire.gov.uk/highways-improvements-a350

12 April 2018

The added carriageway is now surfaced and traffic is running single file in the coned-off left lane of each direction. The separator triangle on the Badger roundabout is still to be addressed, the original single lane one is still in place. Whether the original carriageway will now be replaced is yet to be seen - this has happened on the other dualled sections and may be needed from the point of view of alignment harmonisation for the the concrete central reservation / barrier - but at present there is no sign of a "crossover" lane at the Badger roundabout end to allow two-way running on the new carriageway for this to happen (though at present the triangle is probably in the way). The concrete central reservation is not yet constructed along the length of the new section, it remains grass.

5 September 2018

The Badger to Brook roundabouts section is now apparently complete, all lanes running in both directions.

More information


With thanks to Tim Hewett and Mark Scott for information on this page.