UK motorists could be losing over GBP170 million of fuel every year by neglecting to check their tyre pressures, a new survey by Michelin reveals. Michelin's research found 55 per cent of car and van tyres on UK roads to be under-inflated by an average of 10 per cent. This - the equivalent of a mere three PSI in a tyre that should be inflated to 30 PSI - decreases the fuel efficiency of the vehicle by one per cent. Thirty per cent under-inflation can increase fuel consumption by four per cent, which is equal to 3.4p in every litre. It also more than halves tyre life.