About 11 million cars are expected to take to the roads on Thursday as the Easter holiday getaway begins.
The AA has estimated about half of all drivers will be on the road as holidaymakers mix with school and commuter traffic.
Roadworks across 97% of the motorway and A-roads were due to be finished or lifted by 06:00, but 57 sets will stay in place for safety reasons.
Engineering work will affect about 5% of rail routes over the next week.
The £60m investment is being made because school holidays are traditionally quieter.
Meanwhile, Heathrow Airport is expected to see 850,000 people travel through it this weekend.
Some 200,000 more families than usual will use it over Easter.
The AA said it expected Easter to be busier than last year, with 11 million vehicles on the road, after a survey of its members suggested 55% planned to go somewhere by car on Thursday, compared with 47% in 2015.
The number is expected to fall to 50% on Good Friday.
The average journey for anyone travelling for leisure is expected to be about 35 miles (56km), with roads through Hampshire, Wiltshire and Somerset expected to be among the busiest.
Max Holdstock, from the AA, said: “Despite a more chilly Easter coming up, we expect more people to head out on the road. There will be a lot of pressure on the main getaway routes, particularly heading down to south-west England. and the likes of the M25, M1 and M6 are also going to be very busy.
“With around half planning to visit friends and family, there will be many people racking up quite large distances. For some, it will be their first long-distance car journey of the year, which can reveal underlying mechanical problems that didn’t manifest themselves during short winter trips.”
Highways England said it planned to finish or lift 208 sets of roadworks in time for the getaway. Work on 75 sites will not start again until just after midnight on Tuesday 29 March.
However, 57 sets of roadworks will stay in place because they have large excavation or major structural projects which would make them unsafe to lift. They include five miles worth of narrow lanes on the M6 between junctions 19 and 20 near Knutsford.