There is a warning petrol and diesel prices are due to go up at the pumps.
A price increase is expected in the coming days because of the shutdown of large refineries on the Gulf Coast of the US due to Hurricane Harvey.
Two major fuel pipelines in the US have been restricted or stopped because of flooding, and drivers in Dallas had to queue to fill up their vehicles as some petrol stations ran dry.
"One quarter of the refining capacity in the States remains offline, leaving a shortfall of over four million barrels a day," said RAC spokesman Pete Williams.
"Americans are wedded to their petrol engines and while they have been endeavouring to become more self-sufficient through increased fracking, they are now having to buy more unleaded from overseas, which is reducing the availability of unleaded for the rest of the world."