Three firms have been awarded the contract to start work on the £1bn M4 relief road project around Newport.
The Welsh Government has jointly awarded it to Costain, Vinci Construction and Taylor Woodrow.
The plans include 14 miles of new motorway and a one-mile long viaduct over the River Usk.
It will also mean major re-modelling of M4 junctions 23 and 29 with development work starting immediately despite a legal challenge to the proposed route.
