Wales’s Brynglas Tunnels in Newport

The M4 passes beneath Brynglas Hill near Newport, Wales, via the Brynglas Tunnels. The first and only twin-bored tunnels in the UK road network are the 360-meter (390-yard) tunnels.

In August 1959, Newport Corporation proposed a design to the Ministry of Transport that included the tunnels and the nearby M4 motorway Usk bridge. On September 10, 1962, work on the £3 million tunnel project, headed by engineer Sir Owen Williams, began. On May 5, 1967, both buildings were finished and accessible to traffic. A number of homes on Brynglas Road, where the present-day Newport Lodge Hotel is located, had to be removed during construction because of structural flaws brought on by the tunnelling, which raised concerns in the House of Commons.

Congestion in Traffic

Traffic levels increased to the point where the M4 Newport bypass (junctions 24-28) had to be extended to three lanes in each direction almost immediately after it opened. With the exception of the tunnels and the Usk bridge, which remained dual two-lane sections (Junctions 25–26), this was completed in 1982. In an effort to minimise traffic through the tunnels, M4 sliproads at Junction 25 (Caerleon Road) are rerouted. Junction 25A/A4042 (Heidenheim Drive)/A4051 (Malpas Road) to Junction 26 is the diversion for M4 westbound traffic entering at Junction 25. Similarly, the A4051/A4042/Junction 25A is used to reroute eastbound traffic from Junction 26 that wishes to exit at Junction 25. During rush hours, this exacerbates traffic on Malpas Road and other nearby minor roads close to Newport’s city centre.

The motorway’s tunnels continue to be a bottleneck. Between junctions 24 and 28, there is a variable speed limit, in part because of frequent tailbacks at the tunnels.

On July 15, 2009, the National Assembly for Wales abandoned the plan to build a new M4 relief road south of Newport. The alternate route is still the A48 Southern Distributor Road, a two-lane dual carriageway that runs from M4 junction 24 to junction 28. The National Assembly for Wales released consultation alternatives in March 2012, one of which was the possibility of boring additional tunnels.

Fire

A truck fire on July 26, 2011, forced the closure of both tunnels.

As it entered the west-bound tunnel entrance, the articulated lorry caught fire. The truck was unable to leave the tunnel because of the extent of the damage. The driver’s attempts to unplug the cargo area from the truck’s cab were unsuccessful. The truck’s tires began to burst as the fire grew, and the driver was pulled to safety by another driver who had pulled over farther back near the tunnel’s entrance to keep cars from following and from entering the smoke-filled tunnel. Although no fatalities were reported, the closure resulted in significant traffic delays in both directions.