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The Welsh Government’s traffic information service for motorways and trunk roads in Wales

A465 Dowlais Top to Hirwaun (section 5 and 6)


Start Date: Spring 2021 | End Date: Mid 2025

A465 Heads of The Valley Dowlais Top Junction

The A465 will be changed to 2 lanes in each direction from Dowlais Top to Hirwaun. 

For more information about this project, please see Welsh Government links on the right, for information on traffic management see details below.


This work is taking place on a 17km section of the A465 road, between Dowlais Top, Merthyr Tydfil and Hirwaun. The existing A465 was built in the 1960s and a traffic study identified the need to improve the road by:

  • making the road safer, especially around junctions and areas with poor visibility
  • improving traffic flow and make it safer to overtake

To complete these complex and long term roadworks, the contractor will sometimes need to:

  • reduce the road from 3 lanes to 2.
  • close sections of the road overnight or over weekends
  • use traffic lights to control traffic flow during the works.

The speed limit has been changed to 40mph to protect the safety of road workers on site and the public. This will be enforced in the same way as the existing speed limit using average speed cameras.

Free recovery will be available for vehicles breaking down in the roadworks area.



  • Cefn Coed to Dowlais Top Roundabout

24 hour closures in both directions from 02/07/21 20:00 to 05/07/21 06:00. This is to build access points off the A465 and temporary roundabouts at Cefn Coed on the A465. Tree clearance works will continue at Cefn and Pant

  • A470 Cefn Coed Roundabout to Llwyn-on village (junction of A4054)

Overnight closure for 1 night 26/07/21 from 20:00-06:00 to build access points off the A465.


  •  Cefn Coed to Hirwaun Roundabout

Overnight closure in both directions for 1 night 09/08/21 and 17/08/21 from 20:00-06:00. Western Power utility works to remove of the safety netting over the A465, west of the A470 roundabout.


**Please note this programme may be subject to change. Further closure updates to follow.


The Welsh Government appointed Future Valleys Construction as their partner to help deliver the project. The South Wales Trunk Road Agent is not responsible for the maintenance on this section of the road.

Follow @TrafficWalesS on Twitter for the latest traffic management measures on this road. Enquiries about the works will be directed to the Future Valleys team. 

To report incidents or issues on the network, please call the A465 control room on 0787 287 1702. The line is available 24/7.

For community queries or complaints please call 0776 245 1850 or email: [email protected].

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