Drivers can now access the M4 motorway in London between junctions 1 and 2, although the section between junctions 2 and 3 remains closed, road officials have confirmed.
The Highways Agency shut part of the motorway between junctions 1 to 3 on Friday night to conduct maintenance works to the Boston Manor Viaduct, which contained a crack in a "highly stressed zone".
While the area between junctions 1 and 2 has been reopened to allow traffic to flow in both directions, it is thought the road between junctions 2 and 3 will stay closed until around Thursday.
Motorists using the M4 to get to west London have been asked to consider a different route either using the M3 or the M40 motorways. They can then rejoin the M4 at junction 2, while those travelling out of the capital can stick to the motorway and turn off at junction 2. Road staff have also set up diversion routes on the A312 and the A4.
A Highways Agency spokesman said: "We expect the ongoing programme of repairs will be completed to enable the viaduct to operate in its full capacity in time for the London 2012 Olympic Games later this month."
The M4 is the main route for motorists driving from the capital to Heathrow Airport, as well as to the West of England.
Copyright Press Association 2012