M48

Construction of a new dual three-lane motorway to the south of Newport, from junction 23 of the existing M4 to junction 29, in order to replace the existing motorway which suffers severe operational and congestion problems.

This solution has been chosen partly because widening the M4 and bringing it up to modern standards would be prohibitively difficult - in particular with regard to the Brynglas Tunnels and the twisting alignment.