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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.


  • A465 Hirwaun to Cefn Coed overnight closures in both directions 

Monday 31 January from 20:00 until 06:00 Saturday 5 February for 5 nights to repair the road surface, potholes and undertake other routine maintenance activities.


  • 24 hour lane closures at these locations:

A465 Rhigos Roundabout to Dowlais Top in both directions.

A465 Glyn-Neath Interchange to Rhigos Roundabout in both directions.

A465 from Asda Roundabout to Dowlais Top Roundabout southbound.

A465 Dowlais Top Roundabout outside lane. 

A470 Cefn Coed Roundabout to Swansea Roundabout southbound.


A4054 High Street Bridge
An adjacent section of the network will be closed from 13/09/21 for approximately 18 months. Local diversion in place.

Lon Grawen
An adjacent section of the network will be closed from 15/11/21 for approximately four months to change the direction of water pipes. Access for Lon Grawen residents only.

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 0800 865 4650. The line is available 24/7.

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

Call the Traffic Wales information line
0300 123 1213
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