Start Date: 9/6/25 End Date: 30/11/25
Work to carry out essential bridge maintenance to 5 structures on the M4 between junctions 37 and 38 –will commence on 09/06/2025 and continue over a duration of 6 months.
The work will be carried out over a 6 month programme in four main phases:
Preparatory works to set up the contraflow system
9 June (20:00) – 10 June (06:00)
- Overnight closure westbound for 1 night on the M4 between J37 Pyle to J39 Groes.
10-12 June (20:00-06:00)
- Overnight closure in both directions for 2 nights M4 between J37 Pyle to J39 Groes.
12 June (20:00) – 13 June (06:00)
- Overnight closure westbound for 1 night on the M4 between J37 Pyle to J39 Groes.
13-15 June (20:00-06:00)
- Overnight closure eastbound for 2 nights on the M4 between J38 Margam to J37 Pyle.
Phase 1- Central reserve works
15 June (06:00) – 16 July
- Phase 1 - Central reserve works with traffic flow reduced from three lanes to two lanes in each direction
- A 50mph speed limit will be in place during this time for safety.
- Further details on later phases of works will be published closer to the time.
Night time full closures in both directions will be required in order to install and alter the traffic management measures.
The main works will predominantly be undertaken during daytime.
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.