For months, automakers have been taking a “wait-and-see” approach to the Trump administration’s potential tariffs.

Manufacturers from Asia, Europe and elsewhere have poured billions into North American supply chains that could be hit by new taxes on Mexico, Canada and China.

Patrick De Haan, head of petroleum analysis at GasBuddy, warned Americans in the Midwest, the Rockies and the Great Lakes regions may be most affected by tariffs on Canada.