Up to 31 million British drivers are expected to hit the roads the Easter weekend, causing traffic to increase by around 20 per cent.
According to The Sun, travel information expert Inrix said it expected "significant delays" and "nightmare" journeys, with the most congested times predicted to be 4-6pm on Thursday and 10am-2pm Friday.
The Sun said parts of the M25, M4, M5 and M6 are all likely to have severe traffic jams over the weekend, while journeys could take as much as three times longer than normal.
Saturday is expected to be the busiest day, with Confused.com saying that more than two-thirds of the UK's motorists planning to travel by car.
Amanda Stretton, motoring editor at Confused.com, said: "Bank holidays are always an extremely busy time on UK roads, and an increase in traffic is always to be expected. With 31 million cars predicted to be out and about, drivers should perhaps adapt their plans to help them avoid traffic where possible.
"Planning your route differently or leaving a little earlier can make it an easier and more comfortable experience for drivers. Plus, it should help free up the roads during peak times and ultimately reduce the risk of accidents."
Airports will also be busier as holidaymakers clamour to take advantage of the extended time off. More than 868,000 passengers are expected to pass through Heathrow – 200,000 more than normally seen over the same four-day period on any other week.