Motorists have been warned to expect long delays with 17 million car journeys set to take place over Easter weekend.
Major roads in southwest England and some in the Home Counties are likely to experience the worst congestion on Good Friday, according to the RAC.
The A303 westbound near Stonehenge, the M5 south between Bristol and Bridgwater and the M25 anticlockwise between Hertfordshire and Surrey are all predicted to see more than double the normal amount of traffic.
At times, vehicle speeds are expected to be as slow as 12mph.
Easter Sunday is predicted to see similar levels of traffic with Easter Saturday and Easter Monday only marginally better.
Many will be waiting to see what the weather is like before deciding whether to travel or not, according to the automotive company.
RAC Breakdown spokesman Rod Dennis said: “The south and west of the UK are the areas to watch as they’re home to some vital roads responsible for carrying vast numbers of people to the holiday destinations of the West Country – so our advice to anyone heading that way is to get on the road as early as possible on Good Friday, or travel on a different day entirely.”
Queues are likely to be increased by engineering work on the railways, including the closure of London Euston station over the bank holiday weekend as well.
Those heading to the continent could face even further problems, as holidaymakers have been warned they could face two-hour delays at the Port of Dover over weekend.
People have been urged to “allow 120 minutes to complete border controls and check-in” at the Kent port as the double bank holiday weekend is expected to be “busy”, ferry operator DFDS wrote on Twitter on Thursday night.
At one point on Thursday, there were queues of “approximately 90 minutes” for passport checks by French officials as the Easter rush kicked off, DFDS said.
The company told passengers on Thursday morning this was due to “high volumes of traffic”.
There were chaotic scenes at the port last weekend when thousands of people were delayed, reportedly by up to 14 hours.
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P&O Ferries were advising passengers to expect a 10-hour wait last weekend
Delays at the port have been blamed on French border officials carrying out extra checks and stamping UK passports following Brexit.
Port officials said they held an “urgent review” with ferry operators and the French authorities in an attempt to avoid a repeat of the issues last weekend.
Ferry companies are asking coach operators booked on sailings on Good Friday – expected to be the busiest day for outbound Easter travel from Dover – to “spread the travel” across the three-day period from Thursday to Saturday.
Additional “temporary border control infrastructure” has also been installed.
Transport minister Richard Holden described last weekend’s conditions at Dover as “unacceptable”.
He told Sky News: “I don’t want to see kids on coaches or families in cars queueing up and waiting unnecessarily long periods of time.”
A general strike in France in a row over pension reforms is also adding to the disruption.
Around two million people are expected to head abroad over the weekend, with figures from aviation analytics company Cirium showing 10,218 flights are scheduled to leave British airports between Good Friday and Easter Monday.
Last Easter saw chaos at airports after large parts of the aviation sector failed to hire enough staff to cope with the surge of passengers as COVID restrictions eased.
Airports are running much more smoothly this year, although travellers are advised to give themselves extra time to get to the airport over the weekend, due to increased road traffic.