Start Date: 09/06/25 End Date: February 2025
Work to carry out essential bridge maintenance to five structures on the M4 between junctions 37 and 38.
The work will be carried out over a 6 month programme in four main phases, with works continuing to phases 2 and 3.
Due to bad weather these works have over-run into the end of January 2026.
5 January - 10 January 2026
Overnight closures from 20:00 - 06:00
For Phases 1 to 4, no diversion route will be necessary with all traffic, with junctions 37 and 38 remaining operational.
During the isolated full closures to install traffic management measures, a diversion route will be implemented utilising the A4229 and A48.
Westbound, traffic will be directed off the M4 at Junction 37 and via the A4229 and A48, re-joining the M4 at Junction 39.
For further information, please contact Traffic Wales on 0300 123 1213 or via X @TrafficWalesS and Facebook @TraffcWalesS.