The Brynglas Tunnels carry the M4 motorway under Brynglas Hill in Newport. The 1,200-foot-long (370 m) twin-bored tunnels were the first tunnels in the British motorway network and are still the only bored tunnels.
The tunnels and adjacent Usk bridge were originally planned by Newport Corporation in August 1959 in a plan submitted to the Ministry of Transport. Work started on 10 September 1962 and both structures were complete and open to traffic during the first week in May 1967.[1]
Almost as soon as the M4 Newport bypass (junctions 24-28) had opened, the traffic levels had grown to such a degree that the road had to be widened to three lanes in each direction. This was finished in 1982 but with the exception of the tunnels and Usk bridge which remained as dual two-lane sections (Junctions 25-26). During the original construction several houses on Brynglas Road (where the modern Newport Lodge Hotel now stands) had to be demolished due to structural weaknesses caused by the tunnelling. Therefore the technical challenges and risk associated with widening the existing tunnels in a highly built-up area were found to be too great.
The tunnels remain a bottleneck on the motorway, highlighted by incidents such as the fire in the west bound tunnel on the 26 July, 2011, when both tunnels were completely closed following a major lorry fire.
The articulated lorry, belonging to Hingley Transport, caught fire upon entering the west-bound tunnel entrance, due to the nature of the damage to the lorry it was unable to exit the tunnel. Attempts by the driver to disconnect the cargo-section from the lorry cab failed, as the fire intensified tyres on the vehicle started to explode and the lorry driver was driven to safety by motorist Ashley Hall [2] whom had stopped further back towards the entrance of the tunnel to block and prevent vehicles behind from entering the smoke-filled tunnel. [3]
There were no fatalities recorded, however the closure caused a considerable amount of traffic delay in both directions of travel.[4] Partly due to regular tailbacks at the tunnels, a variable speed limit is in place between junctions 24 and 28.
A New M4 bypass south of Newport was proposed, but on 15 July 2009 the scheme was dropped by the National Assembly for Wales. Hence the A48 Southern Distributor Road, a two-lane dual carriageway connecting M4 junction 24 to junction 28, remains the alternative route.