Under-inflated tyres have been costing fleets more over the last 18 months as fuel prices have risen.

Michelin has found that the average price for diesel has gone up by 14.5% since January 2016.

“Driving on tyres just a few PSI below the manufacturer’s recommended pressures will reduce a vehicle’s fuel efficiency on every single journey. As fuel costs rise, the impact of this under-inflation is pushing running costs higher,” said Jonathan Layton, Michelin’s head of fleet.

Tyre pressures have a direct impact on a vehicle’s fuel economy, with under-inflation increasing both fuel usage and carbon emissions, whilst also posing serious safety risks to motorists and other road users.

“A lot of fleet drivers routinely monitor their average fuel consumption via the dashboard display, and many will even be aware of small differences between journeys. Just imagine how much UK businesses could save if drivers paid as close attention to their tyre pressures as they did to their mpg readout,” Layton added.

UK data collected by Michelin over the last 10 years shows that, on average, at least 60% of motorists drive on under-inflated tyres, and half of those are at dangerously under-inflated levels (more than eight PSI).

As well as increasing fuel bills, under-inflation makes a vehicle’s steering less precise, increases stopping distances and leads to a higher risk of aquaplaning. It also reduces a tyre’s endurance capabilities, making it more prone to damage and possible rapid deflation.

Michelin testing has shown that a tyre which is 20% under-inflated will typically return 20% less mileage before needing to be replaced. That means a loss of 5,000 miles on a tyre which offers a potential mileage of 25,000 miles.