What are flexible-fuel vehicles?

Flexible-fuel vehicles can run either on gasoline or on mixes of ethanol and gasoline. They are identical to gas-only cars except for a few engine and fuel system modifications.

Flexible-fuel vehicles use mixes of up to 85 percent ethanol and gasoline, or E85. FFVs experience no loss of performance, and some even have more horsepower and torque when operating on E85. However, FFVs get fewer miles to the gallon on E85 because ethanol has less energy per volume than gasoline.

FFVs have been on the market since the 1990s, and there are more than 100 models available, as of 2015. They resemble regular cars, but FFVs usually have distinguishing labels to indicate that they can run on ethanol.