This weekend is expected to be the busiest on the roads for years with nearly 19million trips planned between Friday and Monday.
A “frantic Friday” will see an extra 5.61m journeys on the road, with some drivers still unsure of when they will get away.
The data predicts that the M25 could see some of the worst jams, with stretches between Bromley and the Dartford Crossing, Maple Cross to the M3, and the M23 to the M40 to be especially affected.
The research suggests that the UK could see a “staycation” summer, but that high fuel prices could put some of taking to the road or driving further afield into continental Europe.
RAC Breakdown spokesperson Rod Dennis said: “The extreme heat that’s affecting much of the UK in the last few days might wane over the next few days, but we still expect the summer getaway to begin with a bang as a potentially record-breaking number of drivers take to the roads this coming weekend – and that’s despite the unbelievably high cost of fuel.
“With school terms in England and Wales finishing this week and millions of people ready for a well-earned break, we anticipate a ‘frantic Friday’ followed by a woeful weekend on major roads across the country, with traffic and congestion likely peaking on Saturday.
“The advice to drivers heading off on a holiday by car is therefore clear – leave as early as you can in the morning or expect to be sat in some lengthy queues.”
Other areas of the country which could see lengthy traffic queues are the A303 near Stonehenge, M4 between Cardiff and Newport and M5 south of Bristol.
National Highways, which is responsible for motorways and major A roads across the country, has launched a campaign reminding drivers to check their tyres before heading off.
More than 41,500 people broke down on National Highways roads last year because of tyre issues, accounting for over 20 per cent of breakdowns.
National Highways Head of Road Safety, Jeremy Phillips, said: “We know that breaking down can be a very upsetting experience, nobody wants to start off their holiday stranded at the side of the road, next to fast moving traffic.
“So we are reminding drivers to check their vehicles, particularly the tyres, before setting off.”