According to figures from the RAC Traffic Watch, 14.4 million vehicles could hit the road between Thursday and Sunday as schools break up for the summer.
The study, which looked at nearly 1,300 drivers’ plans, revealed that Saturday will be the busiest day, with 4.5 million leisure journeys forecasted.
Traffic levels will also be high on Sunday, as 4.2 million holiday trips by car are expected to take place, while Friday will see some 3.3 million cars added to the usual total.
Holiday traffic on Thursday is also set to be high, with 2.4 million cars predicted to take to the roads.
Overall, the figures show that there will be 5.4 million extra car trips between Thursday and Saturday this year compared to the same period in 2015.
RAC traffic spokesman Simon Williams said that the rise could be explained by spell of sunny weather the country has been experiencing this week.
“Our data shows that the 2016 end-of-term rush for the roads is likely to be dramatically worse than last year’s,” he added.
“Many will inevitably suffer the effects of this traffic overdrive as they look to begin their long-awaited summer holidays.
“If you are one of the 14.4m motorists heading for holiday this weekend from Thursday the best advice is to hit the road as early as you can. Avoiding peak travel times is not easy, but it can mean several less hours spent in the car.”
Drivers are also advised to plan their journeys carefully to avoid peak periods, and to carry out simple checks to make sure their cars are ready for the trip.
These include checking oil, coolant and washer fluid levels, while motorists should also ensure tyres have plenty of tread and pack refreshments to help with the effects of the hot weather.
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When compared to 2015, traffic levels on Saturday this year will be higher, seeing a rise of 1.6 million on the previous figure.
On Black Friday, when million motorists set off early to try to beat the rush, there will be 700,000 more cars on the road than the same time last year.