Gasoline consumption creates externalities, through pollution, road congestion, accidents, and import dependence. What effect would a higher gasoline tan have on the related magnitudes: gasoline consumption, miles driven, and road fatalities? In this paper, separate models are estimated for gasoline use per mile, miles driven per driver, and fatalities per mile driven. We use data from 50 U.S, states and DC for 1970 through 1991, with a variety of stochastic specifications. The own-price elasticity of demand for gasoline is derived from projections with, and without, a higher gasoline tan, and is found to be between -0.12 and -0.17 in the short-run, and between -0.23 and -0.35 in the long-run. A tan of $1 per gallon would cut use by 15-20%, miles driven by 11-12%, and fatalities by 16-18% over 10 years, while raising almost $100 billion in revenue annually.