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 have been warned of possible delays of nearly two 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 Friday afternoon to be busy as shoppers, commuters and people trying to go away for Christmas all use the same roads.

Most roadworks on motorways in England were lifted or finished by 06:00 GMT on Friday but some have had to stay in place for safety reasons.

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

The roads to avoid

Inrix, which provides traffic information, said the section from the end of the M42 to Junction 8A of the M40 south, near Aylesbury, was likely to be very congested on Friday afternoon, with the typical 47-minute journey predicted to take almost two hours longer.

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 2.8m journeys will be made by car 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.

Longest sets of roadworks over Christmas

Highways England said 97% of roadworks on motorways and major routes were 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:

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

No Southern trains to or from London Victoria from Sunday 23 December until Wednesday 2 January

No Gatwick Express service from 23 December until 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

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 Inquiries.