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Brynglas Tunnels

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As part of essential safety works and wider improvements to the M4, planned overnight maintenance at the Brynglas Tunnels at Newport will take place from Monday June 20.
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Brynglas Tunnels

We are refurbishing the Brynglas Tunnels and repairing the Usk River Bridge.


Project status: current
Region/county: Newport
Start date: February 2016
End date: spring 2018
Design contractors: Capita
Build contractors: Costain Ltd

This project is registered with the Considerate Constructors Scheme (external link).

Traffic updates

You can find up to the minute information on road closures on the Traffic Wales website (external link).

Why we are doing 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.

Current progress

We have appointed a contractor who is developing the detailed design. Construction began in June 2016.

The works

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

We are scheduling construction so that any closures for the main works are mostly overnight. Closures will be between junctions 24 and 28, and will usually be in one direction only. The Southern Distributor Road (the A48) will be used as a diversion for the closed section of tunnel. Local traffic will be able to travel to junctions 25a and 26 to access local routes. We may need to close the tunnel in both directions for short periods of time for safety reasons.


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

How we are consulting

We consulted on the decision that the Environmental Impact Assessment was non-statutory between 23 October and 11 December 2015.

We are currently consulting with statutory bodies on the Statement to Inform an Appropriate Assessment.

You can contact Hannah Lewis, Public Liaison Officer using our contact form.

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