M4 relief road

The M4 relief road is a proposed motorway south of the city of Newport, South Wales. Originally proposed in 1991, the scheme was dropped by the Welsh Assembly Government in 2009 when costs had risen to £1 billion. They were revived in 2011 with indications of support from the Treasury given in April 2013. There was controversial media speculation that it would be the United Kingdom's second full toll-paying motorway. In July 2014, the Welsh Transport Minister, Edwina Hart, stated that the scheme, following the so-called 'black route', would go ahead and could be completed by 2022.

A second motorway has been proposed to the south of Newport, running for 14 miles (23 km) parallel to the existing M4 motorway from junction 23A at Magor, to junction 29 at Castleton, avoiding the need to widen the Brynglas Tunnels. The concept behind the motorway was based on the M6 Toll motorway, a relief road built to reduce traffic on the M6 motorway around Birmingham.

The existing motorway runs through the Brynglas Tunnels north of Newport city centre. Like many stretches of motorway, it does not conform to current motorway standards: it lacks continuous hard shoulders due to previous widening, has closely spaced junctions and narrows to a restricted two-lane section through the Brynglas Tunnels, where heavy congestion occurs at peak hours. A variable speed limit is in place between junctions 24 and 28. M4 sliproads at Junction 25 (Caerleon Road) are diverted to reduce traffic through the tunnels. M4 Westbound traffic joining at Junction 25 is diverted via Junction 25A/A4042 (Heidenheim Drive)/A4051 (Malpas Road) to Junction 26. Similarly eastbound traffic wishing to exit at Junction 25 is diverted from Junction 26 via the A4051/A4042/Junction 25A. This adds to congestion on Malpas Road and other local roads near Newport city centre at peak times.

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Wikipedia