Media playback is unsupported on your device Media caption How do you avoid holiday traffic jams?

The Christmas getaway means congested roads and cancelled trains. Drivers are facing potential delays of up to three hours as millions of cars take to the motorways. But where should you avoid and at what times will traffic be busiest?

Traffic experts expect the busiest times to be Thursday and Friday afternoon as shoppers, commuters and people trying to go away for Christmas all use the same roads.

Most roadworks on motorways in England will be lifted or finished by 06:00 GMT on Friday but some will stay in place for safety reasons.

Meanwhile, strike action by South Western Railway and Northern rail workers will come ahead of hundreds of engineering works that will affect major stations including London Victoria and Paddington.

The roads to avoid

Inrix, which provides traffic information, said the M6 motorway north of Stoke-on-Trent is likely to be one of the most congested roads with warnings the journey to Wigan could take three hours longer than usual.

The predictions are based on analysis of traffic flows during previous Christmas getaways. The route also includes 40 miles of roadworks.

The RAC estimates about 2.5m journeys will be made by car on Thursday and a further 2.8m on Friday. Based on a survey of its members, it predicts about 6.8m journeys on Boxing Day as drivers travel to see family and friends.

Joshua Kidd, from Inrix, said: "Compared to a normal day, Thursday will see the biggest increase in cars on the road. With most drivers setting out mid-morning, traffic will become heavier over the course of the afternoon and stay congested into the evening.

"But it's not just those off to see family and friends - commuters, last-ditch shoppers and online deliveries will contribute to clogging the roads."

Longest sets of roadworks over Christmas

Highways England said 97% of roadworks on motorways and major routes would be cleared by 06:00 on Friday and would not resume until 2 January.

There are about 40 sets that will stay in place because it would not be safe to remove them.

Traffic Scotland said most of its roadworks would also be clear but advised drivers to check its website.

When to avoid the trains

More than 330 sets of rail engineering works will take place between Sunday 23 December and Tuesday 1 January.

Network Rail said it would do most of the works when no trains are scheduled to run, including Christmas Day and Boxing Day.

Timetable changes affecting journeys on other days include:

No trains between London Liverpool Street and Romford from Sunday 23 December to Tuesday 1 January

All lines to and from London Paddington closed on 23, 24 and 30 December

No Gatwick Express service from 23 December to Wednesday 2 January

Timetable changes for services to and from Liverpool between Monday 24 December and 1 January, affecting East Midlands Trains, London Northwestern Railway, Northern and Virgin Trains

Replacement buses between Birkenhead Central, Birkenhead North and Liverpool Central from Thursday 27 December to 1 January

Replacement buses between Manchester Victoria, Stalybridge, Rochdale and Salford Central on 27 and 28 December and a reduced service between Manchester Victoria and Stalybridge on Saturday 29 and Monday 31 December. Buses will also replace some services to and from Manchester Victoria on 1 January

Late night and early morning Virgin Trains services between London Euston and Wolverhampton will start and terminate at Birmingham New Street on 27 and 28 December

Image copyright Network Rail Image caption Engineers will work on Christmas Day and Boxing Day but services on other days will face disruption

Workers on South Western Railway (SWR) will go on strike on Saturday 22 December in a long-running dispute over guards.

SWR operates services from London Waterloo to Berkshire, Surrey, Hampshire, Dorset, Devon, Somerset and Wiltshire.

The strike will begin at 00:01 and end at 23:59 GMT. More walkouts are planned for 27 and 31 December.

Northern rail workers represented by the Rail, Maritime and Transport Union will also strike on 22 and 29 December as part of a series of walkouts on Saturdays in December.

Very few trains are expected to run after 17:00 GMT on those days.

Details of all engineering works are available from National Rail Enquiries.