Traffic experts say a Hampshire road is likely to be among the country’s busiest as drivers head off on the May bank holiday getaway this afternoonm.
Motorists have been warned that the bank holiday getaway will add around 25% to normal traffic levels from 3pm until early evening on Friday.
Drivers should delay their journeys until after 7pm to avoid the expected surge in congestion, according to the AA.
Some main routes in and around London and the South East could experience a 50% increase in regular Friday late afternoon traffic, the motoring organisation said.
It expects 10 million motorists to take to the road at some point over the weekend - around a third of all licence holders.
Transport information company Inrix predicted that drivers will be delayed by up to 90 minutes on peak routes.
The main congestion hotspots are set to include the A303 westbound through Hampshire, Wiltshire and Somerset as well as all sections of the M25, the M6 in the West Midlands.
Max Holdstock, AA patrol of the year, said: “May bank holiday traffic tends to be more intense as families and friends decide whether to get away or make the three days off a long weekend at home.
“If people are going to go away, they need to get on with it to make it worth their while.
“For many vehicles it will be their first long-distance car journey of the year, which can reveal underlying mechanical problems that didn’t manifest themselves during short winter trips. Do the essential checks on your car before heading off.”
The RAC estimated that 20 million leisure trips will be made on Britain’s roads between Friday and Monday.
It claimed a “far greater” number of cars will be on the highway this May Day weekend compared to 2015 because a number of people are making up for not going away at Easter as it was earlier than normal.
Green Flag said more than 31,000 breakdowns will take place this weekend.
Meanwhile, those hoping to avoid the queues on the road by taking the train will find that a number of lines are disrupted due to engineering work.
Virgin Trains, Great Western Railway and TransPennine Express are among those affected.
Network Rail (NR), which manages Britain’s rail track and major stations, claimed it will be “one of the least disruptive bank holidays for railway travel for many years”.
It said £33 million of improvement work will be carried out over the weekend, when fewer than half the usual number of passengers are expected to travel.
Buses will replace trains between Glasgow Central and various parts of north-west England between Saturday and Monday due to work on the West Coast Main Line.
Signalling improvements on the northern part of the Midland Main Line mean major alterations to services, including replacement buses running between Manchester Piccadilly and Sheffield on Sunday.
London Paddington will see reduced services over the weekend as Crossrail and electrification work continues.
No Gatwick Express services between the West Sussex airport and London Victoria will operate during the weekend. Fast, direct services will run to and from London Bridge instead.
More than 96% of the rail network will be unaffected by the engineering work, NR said.
The company’s chief executive, Mark Carne, said this was “good news for passengers”.
He said: “We’re continuing with our huge investment programme and we have a lot of work to do this weekend, but we’ve planned it as far as possible to minimise disruption.”
National Express said it is adding 8,000 extra seats to its services between Friday and Monday to cope with demand, which has been boosted by the engineering work on the railways.
The operator predicted that Friday will be its busiest day, with London being its most popular destination followed by Birmingham, Bristol, Leeds and Manchester.