The estimated 4 million people taking a short "staycation" in the UK should expect the busiest traffic on the roads Friday, as the bank holiday weekend begins.
Motoring organisations expect numbers to fluctuate with the weather forecast, and the Met Office has dampened earlier hopes of a renewed heatwave.
According to a VisitEngland survey, more than 2 million more people were waiting on the weather before deciding on a short break at home.
Traffic in the south-east will be around 35% higher than usual on Friday afternoon, according to analysts INRIX, which reported summer traffic on the roads up 20% from 2012. Peaks in the Midlands and north-west are expected between 4pm and 5pm on Friday as thousands head to the Lake District. The AA said up to 16 million drivers would be on the roads. Drivers planning to take motorways in the heart of England are advised to travel in the morning or evening if possible.
For return journeys on bank holiday Monday, traffic is anticipated to be high in the south-east all day, peaking at around 11am. South-west traffic levels will be highest around 1pm while traffic to the Midlands will peak at 5pm.
The Highways Agency has suspended 151 miles of roadworks for the weekend, which it said meant that 98% of England's motorways and other strategic roads would be free from roadworks. However, it said moderate delays should be expected on parts of the M6 and M25 where works could not be lifted. Two 20-mile stretches of the M25, between junctions 23 and 27 near Potters Bar and 5 and 7 near Godstone, will have speed restrictions and narrow lanes. Similar conditions will apply from junctions 5 to 8 of the M6 near Birmingham, with junctions 37 to 39 near Tebay also having lane closures and contraflows. The agency also warns of delays on the M275 near Portsmouth.
Other roads the AA and Trafficmaster expect to be hotspots include the A303 westbound from M3 junction 8 to the A30 at Upottery, Devon; the M3/M27/A31 southbound from junction 9 (A34) to M27 at junction 13; and the M4 westbound from junction 1 to 13, and then again from junction 18 (Bath) to the Almondsbury interchange with the M5. The M5 west from there to Exeter could also be busy.
Network Rail and train operators said it would be a relatively pain-free bank holiday for most passengers with few disruptive or major engineering works. Most of the planned works are set for Sunday with the majority of passengers unaffected and rail replacement buses kept to a minimum. Works will though mean longer journeys on parts of the West Coast main line, for example,, doubling travel times from London to Manchester on Sunday. In the capital, a strike by RMT members will drastically reduce services on much of the London overground on Sunday and Monday.
Around 1.8 million Britons will be heading overseas at the weekend, according to travel organisation Abta, with almost a quarter leaving via Heathrow airport.
Things to do this bank holiday
• Notting Hill carnival, west London, Sunday & Monday Free. One of the world's biggest street festivals . Up to a million visitors are expected to come to soak up the atmosphere.
• Reading and Leeds festivals, Friday to Sunday At Richfield Avenue, Reading and Bramham Park, Wetherby. Reading sold out, Leeds weekend tickets £60-£200. Headliners are Green Day, Biffy Clyro and Eminem.
• Newlyn fish festival, Cornwall, Monday £5. From fish curries to barbecued lobsters, a foodie's paradise set in Newlyn harbour.
• Paw pageant, Old Spitalfields Market, London, Monday Free to spectate, £5-£8 to enter. Canines meet designer clothing at this charity fundraiser, with all proceeds going to Battersea Dogs and Cats Home.
• Manchester Pride 2013: Big Weekend, Canal Street, Friday to Monday Free. The award-winning celebration of lesbian, gay, bisexual and transgender life. Saturday's pride parade, the highlight of the weekend, has the theme: "Acceptable in the 80s?"
• Liverpool international musical festival, Friday to Monday Various locations, ticket prices range from free to £20. Artists include JLS, Soul II Soul, Neil Young, Little Mix and the Royal Liverpool Philharmonic Orchestra.
