<human>:  What kind of car has the best gas mileage?
<bot>: The car with the best gas mileage depends on a variety of factors, including engine size, the type of vehicle, and the type of fuel it uses. Generally, small cars with four-cylinder engines, such as a Honda Civic or Toyota Corolla, tend to have the best gas mileage. Hybrids and electric cars tend to be some of the most fuel-efficient vehicles as well.