Emergency repair work has allowed the M4 motorway between central London and Heathrow to reopen.
The M4 had been shut in both directions between junctions two and three in west London since last Friday after a crack was found in the Boston Manor viaduct.
It was closed by the Highways Agency following the discovery in a “sensitive area” of the road structure.
The agency had earlier said it expected all work to be finished before the start of the London Olympic Games.