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We refurbished the Brynglas Tunnels and undertook repairs on the Usk River Bridge.

Region / County:
Start date:
29 February 2016
End date:
July 2018
First published:
31 July 2018
Last updated:


Why we did it

The tunnels were built under old design standards and are no longer compliant with current design standards. In addition, the Usk River Bridge and Malpas Viaduct need essential maintenance.

The works

This work involved replacing all the mechanical and electrical systems in the tunnels, as well as the carriageways, drainage and the lining of the tunnel. We also resurfaced the Usk River Bridge.

Construction was scheduled so that any closures for the main works were undertaken mostly overnight.

We have completed the works. Which should reduce future maintenance operations on this section of the M4.

For information on closures visit the Traffic Wales website.


Design: from 29 February 2016 for 24 weeks
Construction start: 20 June 2016
Construction end: July 2018


Reports, environmental statements and plans