Environmental campaigners Friends of the Earth and sustainable transport charity Sustrans have both condemned the decision to go ahead with a new motorway. They claim it will devastate nationally important wildlife sites in the Gwent Levels south of Newport. They also predict that the motorway won't open to traffic for more than a decade and that the billion pound cost will starve more worthwhile transport projects of funds.
Matt Hemsley, from sustainable transport charity Sustrans ,says the the Assembly should make the introduction of more speed restrictions part of future policy.
"Slower speeds limits really encourage people to get out and walk and cycle, which is really good for their health" he says.
"Fast-moving traffic in communities really puts people off".