M4 corridor bridge, serving Chepstow, being renumbered the M48, although the area is still generally considered as falling within the M4 corridor. Since the start of the 21st Century there has been evidence of more investment west of Cardiff, such as: M4 corridor The M4 corridor is an area in the United Kingdom adjacent to the M4 motorway, which runs from London to South Wales. It is a major high-technology hub. Important cities and towns linked by the M4 include (from east to west) London, Slough, Bracknell, Maidenhead, Reading, Newbury, Swindon, Bath, Bristol, Newport, Cardiff, and Swansea. The area is also served
M4 relief road 2014 plans could jeopardise future investment in the area. Matthew Kennerley of ABP said: "We don't think it's a great idea to put the new route through the centre of Wales' most important general cargo port. We believe there is an alternative route...slightly further north...[which] would still have an impact on the port but to a much lesser extent because it would not be bisecting very important quayside areas." 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 Government