Drivers have been warned to expect "significant delays" over Easter with more than 20 million cars expected on the roads between Maundy Thursday and Easter Monday.
Traffic is set to peak at 28% above typical levels at 5pm on Thursday as motorists embark on the bank holiday getaway as soon as the working week is over, according to transport information supplier Inrix.
It said the worst affected roads will be major motorways, with some journeys taking as much as three times longer than normal.
Drivers between Junctions 9 and 21 on the M25 should expect delays of up to 90 minutes, extending a typical 40-minute journey to more than two hours.
Motorists heading in both directions on the M6 and southbound on the M5 towards the West Country should also prepare for hold-ups of almost an hour, according to the report.
Inrix said the worst times to travel will be:
:: Thursday between 4pm and 6pm
:: Friday between 10am and 2pm
:: Monday between 12pm and 5pm
Easter Sunday is expected to be the quietest day on the roads with 25% fewer vehicles compared with an average Sunday.
A number of rail services will be disrupted as Network Rail carries out more than 200 engineering projects.
Trains to London, Manchester, Bath, Edinburgh and Glasgow are among those affected.
Network Rail said it is carrying out the work over the four-day weekend as fewer passengers use the railways on bank holidays.
Airports are also expecting a rush of holidaymakers jetting off overseas.
Some 868,000 people are due to travel through Heathrow Airport between Good Friday and Easter Monday, including an extra 200,000 families compared with a typical Friday to Monday period.
Inrix head of research Graham Cookson said: "With UK drivers spending an average of 30 hours in congestion last year, motorists are no stranger to sitting in traffic.
"We expect significant delays over the Easter period due to a combination of factors, including the regular post-work peak, the start of the school break, people travelling on holiday, railway engineering works and Tube closures.
"Our advice to drivers is to consider alternative routes or avoid peak times altogether."
Highways England said it has lifted more than 300 miles of roadworks ahead of the Easter getaway, meaning almost 98% of motorways and major A roads will be fully open.
:: These are expected to be the 10 most delayed routes on UK roads on Thursday, according to Inrix:
:: M25 between J9 and J21 (both directions); 90 minutes
:: M6 between J16 and J22 (both directions); 50 minutes
:: M5 southbound between J14 and Weston-super- Mare; 45 minutes
:: M4 westbound between J2 and J13; 45 minutes
:: M25 anti-clockwise betweeen J4 and Dartford Tunnel; 40 minutes
:: M8 eastbound between J16 and J8; 30 minutes
:: A34 northbound between Abingdon and M40; 30 minutes
:: M60/M62 between J8 Carrington and J20 Rochdale; 30 minutes
:: A303 Andover to Amesbury westbound; 30 minutes
:: M74 between J4 and J5 southbound; 20 minutes