As schools, factories and offices close for the festive fortnight, the RAC is predicting worse traffic than last year.
It is advising motorists to avoid travelling on Friday afternoon and early evening with an after-work rush expected to trigger a meltdown on the roads with hour-long jams expected.
The dash to join family and friends for the four-day holiday weekend will also clog major routes on Saturday.
The motoring organisation said the worst hotspots will be the M25 and M4 near Heathrow, the M4 north of Newbury, Berkshire, the M62 near Warrington, Cheshire, the M5 near Avon-mouth and the M6 in Cumbria.
RAC spokesman Simon Williams said: “Friday’s clash of getaway leisure traffic, commuters finishing work and business vehicles will make it one of the worst days on the roads over Christmas.
“Leave in the early morning or late evening to avoid pinch points on the road network, otherwise you’ll be sitting in jams.
“More cars will be on the roads this Christmas than a year ago.
“Rail engineering works will force some people to take to their cars. And factor into journey times that not all roadworks on main routes will be suspended – and don’t forget local roads will still have roadworks on them.”
Around 174 miles of trunk route roadworks will stay in place over Christmas, as will 1,714 local authority and utility company projects, RAC data showed. Rail passengers will be pushed on to roads by engineering works delaying mainline routes from London to the West, North-East, North-West, South-West, and East.
It is part of Network Rail’s £127million outlay on 275 works projects. Christmas Eve will see rail shutdowns from London’s Paddington, King’s Cross and Victoria stations.
There are also line closures from York to Darlington in the North-East, while on the south coast, Southampton will have no train service.
Norman Baker, the former Transport Minister and Campaign for Better Transport spokesman, said: “It’s unfortunate that disruption will take place as people travel to see loved ones.”
But Andrew Haines, Network Rail chief executive, said: “We’ve worked with operators to ensure the vast majority of the network is open. But some key upgrade projects will have an impact.”
Airports are also set to be busy with four million people preparing to fly abroad. Long queues are expected at security and check-in desks, with Heathrow and Gatwick braced for more than 500,000 passengers in the coming days.
The Caribbean and skiing in Europe are proving to be the most popular destinations.
Travel watchdog ABTA said: “Despite cost-of-living pressures the appetite for travel is strong.”
But some passengers will be stalled by rail works, with the Heathrow Express suspended from December 24 to 27, and no Stansted Express from London Liverpool Street on Boxing Day.
The Port of Dover is also expected to be busy from Friday as families head to the Continent.
