An increase in the price of gasoline will increase the usage costs for all automobiles, although the cost-per-mile increase will be greater for less fuel-e cient cars. If there were su ciently attractive substitutes for cars as a whole, we might expect across-the-board increases in usage costs to decrease demand for all car models. For what is probably the vast majority of car owners, however, abandoning car ownership entirely and instead relying completely on other forms of transportation is unlikely to be a realistic choice. 1 If this is the case, we expect demand for cars in general to be inelastic to changes in fuel prices. Instead, we should.