The great summer getaway has begun, with millions of families expected to mark the school break-up by heading for holiday destinations .
Britain's roads could become "battlegrounds" as those eager to get an early start to their summer break mix with Friday afternoon commuter traffic.
The RAC described today as "Black Friday" - a phrase most recently used by companies to stir up hype for one of the most popular pre-Christmas shopping days.
The roads are most likely to be busy between 4pm and 9pm today, and 9am and 4pm tomorrow. The RAC said it is expecting around 7.5 million motorists to hit the road by the end of the weekend.
RAC head of external affairs Pete Williams said: "Our data shows that summer holiday traffic is going to be concentrated on our roads this coming weekend, causing gridlock and delays for many on the busiest 'getaway' routes.
"We're expecting 'Black Friday' to be particularly hectic, as the majority of families will be squeezing their journeys into the end of the day."
Those stuck on motorways tomorrow will be queuing in summer sunshine, with the Met Office predicting clear skies across the UK and highs of around 23C (73F).
Those heading into Europe will be doing so against a backdrop of attractive exchange rates.
Sterling rose to just under 1.44 euros, meaning that travellers who set out after many schools break up for the summer today will be able to exchange £500 for 696 euros - 132 more than two years ago.
It is the pound's highest level since November 2007 and up 15% compared with this time last year, with analysts predicting that it could soar to 1.5 euros.