Millions of drivers are expected to take to the roads as the school summer holidays begin and tourists head to the South West.
The RAC estimates more than 11 million motorists will make trips this weekend - with Friday 23 July expected to be the busiest of the three days.
A number of West Country roads will be badly affected, including the M5 motorway through Somerset and Devon, the A303 in Wiltshire and the A38.
More people are expected to travel to the region this summer while restrictions remain in place on holidaying abroad.
Scroll down for the latest traffic updates.
Latest traffic updates for the West Country
Holiday traffic - 2.45pm update:
M5 southbound between Gloucestershire and Bristol - severe delays and stop-start traffic due to holiday traffic on M5 Southbound from J15 M4 J20 (Almondsbury Interchange) to J22 (Burnham-on-Sea ). Travel time is 1 hour 20 minutes.
‘Incredibly busy few weeks’
RAC spokesperson Simon Williams said roads will likely be busier than normal for the next few weeks.
“With the current heatwave, the scene is really set for an incredibly busy few weeks on the country’s roads, whether that’s on motorways or on smaller, minor routes that take people to popular tourist destinations by the coast or in the countryside,” he said.
“With the roads likely to be so busy, we’re expecting the numbers of people needing our help to rocket, but it’s not too late to reduce your chances of breaking down.
“This is why we can’t stress enough how important checking tyres, oil and coolant levels is.”