Fleets are being warned to expect double bank holiday traffic trouble for drivers over the next two weekends with up to 32 million separate leisure trips by car planned, according to RAC Breakdown research.

With millions of people set to enjoy two bank holiday weekends in a row thanks to the King’s Coronation this year, the RAC estimates this coming weekend will be the busiest May bank holiday since 2016 with around 17.2m individual trips – marginally more than over the same period last year.

The Coronation weekend is forecast to be slightly less busy with 14.6m journeys.

The RAC together with transport data experts Inrix expect this Friday and Saturday to see the greatest numbers of drivers taking to the road, and hence the longest delays – with Friday afternoon and early evening likely to see congestion as leisure and end-of-the-week commuter traffic combine.

Drivers are planning an estimated 2.3m trips on Friday alone, with Saturday seeing the weekend peak of 2.7m journeys and an extra 7.6m taken at some point over the whole weekend.

Inrix is warning drivers to be aware of the potential for long delays on the M5 southbound between J15 Bristol and J23 Taunton on Friday (April 28), as well as the M6 northbound from J18 Chester to J24 Liverpool around the same time – with queues of at least 30 minutes expected.

Drivers are advised to set out before 11am if they possibly can or leave their journeys until later on Friday evening, or early on Saturday if they can, to have a better chance of missing the worst of the jams.

Over the Coronation long weekend, the RAC anticipates an even spread of traffic – around 2m trips each day – with the afternoon of Friday, May 5, and Saturday, May 6, likely to see the most congestion.

RAC Breakdown spokesman Rod Dennis said: “While we’d expect more short breaks and day trips to the coast this coming weekend, when it comes to the Coronation it’s likely major routes are less likely to be congested.

“The big variable, as always, is what happens with the weather. If temperatures finally increase and the sun makes more of an appearance, we could well see many more people jumping in the car for a quick trip.”

Bob Pishue, transportation analyst at Inrix, added: “Although delays won’t be as severe as Easter, drivers should expect long delays on major roads in and around greater London this weekend.

“Travel times will likely peak on Friday afternoon with some areas seeing double the travel times as holiday travellers mix with commuters, but drivers should be prepared for added congestion throughout the holiday weekend.”