Last updated: 11 April 2017

Where & Why?

Highway maintenance resurfacing works on the M4 between Junction 35 and Junction 37 (both westbound and eastbound carriageway). These works are essential, safety critical highway maintenance works and are required to ensure the long term integrity of the carriageway.

Diversions & Safety Measures

Works will commence on Wednesday 8th February 2017.

Traffic management will be in place to protect the workforce and manage the flow of traffic. Every effort will be made to minimise inconvenience to road users.

The works will be undertaken at night between the hours of 8pm and 6am utilising full road closures. During the closures, signed local diversions will be in place and advance notification signs will be provided. Please note that the works are primarily between J35 and J36 but the diversion has to be implemented between J35 and J37. The works are to commence on the westbound carriageway and will then transfer to the eastbound carriageway. The works are programmed to be completed in April 2017, weather permitting.


For further information, please contact South Wales Trunk Road Agent (SWTRA) on 0300 123 1213, select 2 for English, then select 2 for road maintenance issues.

SWTRA anticipate updates will be provided as required and when there are notable changes in programme duration. Please check this page for the latest information.