A multi-vehicle pile-up on the M4 near Bristol is expected to cause problems for motorists for most of the day.
The motorway has been closed between junctions 21 and 20 Eastbound near Almondsbury following the crash.
Fire and ambulance crews are at the scene. One man is reported to be trapped in one of the vehicles.
Police are advising drivers to avoid the area if at all possible.
Vehicles travelling from the west along the M4 are being urged to use the M49.