The main exception to this rule is terms related to cars and the auto industry. Because Canada's auto industry has always been dominated by American firms, Canadians use American words and spelling for such terms. Canadians and Americans spell the outer rubber portion of a wheel as "tire" instead of "tyre", put "gasoline" or "gas" in their vehicles instead of "petrol", store items in the "trunk" instead of the "boot", and may drive a "truck" instead of a "lorry".