Motorists are being warned to plan their journeys before they take to the roads over the Easter holiday as new traffic estimates suggest nearly 10 million cars will be on the move during the period.
Trafficmaster expects a further eight million cars to hit the roads over the royal wedding weekend at the end of the month.
The list of top potential congestion hotspots, compiled by the traffic information company, includes the M5, A303, A30 and A38 in the West Country, the M3 around Winchester in Hampshire and the A21 through Sussex, and roads leading to the Channel Tunnel and the Channel ports.
Other motorways most likely to be congested are the M11 to Stansted Airport in Essex and the A12 to the East Anglia coast, the M1 in the East Midlands and South Yorkshire, as well as the M6 in the West Midlands, Lancashire and the Lake District.
The M56 and the A55 between Manchester, Chester and along the North Wales coast, and the M90, A90 and Forth Road Bridge between Edinburgh, Fife and Tayside in Scotland are also expected to see heavy traffic over the Easter period.
Busier evening rush hour is forecast on Friday as people head off early, with traffic remaining heavy over the weekend, especially in London and south-east England, with the FA Cup semi-finals at Wembley and the Virgin London Marathon on Sunday.
The RAC warned that roads around theme parks, shopping centres and retail outlets were likely to be busy over Easter.
RAC patrol ambassador of the year Kevin Andrews said: "People need to plan their journeys before setting off.
"Allow plenty of time for your journey, particularly if you're heading for a popular resort or travelling at peak times."
Copyright © Press Association 2011