Now there are vehicles that run with ethanol or gasoline or both of them. North American vehicles can run on 10% ethanol/90% gasoline with no modifications. Going beyond 10% ethanol generally requires special engineering. Flex Fuel vehicles can accept up to 85% ethanol. As E85 is more corrosive, special fuel system materials are also required. Flex Fuel vehicles can run with unleaded gasoline, ethanol or both of them any proportions.

PROTEX Fuel Additives can be use with Flex Fuel vehicles.