FUEL SAVINGS AND INCREASED HIGHWAY SAFETY APPEAR TO BE THE TWO MOST IMPORTANT GOALS OF THE 55 MPH SPEED LIMIT. A THEORETICAL JUSTIFICATION FOR THE SPEED LIMIT IS GIVEN, FOLLOWED BY AN EMPIRICAL ANALYSIS OF THE SPECIFIC SPEED LIMIT INSTITUTED IN THE UNITED STATES. REASONABLE DOLLAR VALUES FOR BENEFITS OF THE 55 MPH SPEED LIMIT WERE ESTABLISHED, AND RELEVANT COSTS RESULTING FROM THIS CHANGE IN POLICY WERE ESTIMATED. ALTHOUGH BASED ON ROUGH CALCULATIONS, THE EMPIRICAL ANALYSIS INDICATED THAT THE BENEFITS OF THE PROGRAM OUTWEIGHED THE ECONOMIC COSTS. THE SPEED LIMIT POLICY WAS ALSO FOUND TO BE THE SECOND, OR THIRD, BEST CHOICE FOR ACHIEVING BOTH SAFETY AND CONSERVATION GOALS; ALTERNATIVE POLICIES COULD BE MORE EFFECTIVE AND ELIMINATE THE PRESENT INEQUITY OF PENALIZING, IN TIME COSTS, DRIVERS OF EFFICIENT COMPACTS AND GAS GUZZLERS ALIKE. POLICIES THAT COULD REPLACE OR COMPLEMENT A NATIONAL SPEED LIMIT INCLUDE RAISING GASOLINE PRICES BY IMPOSING TAXES OR TAXING CARS ON THE BASIS OF RATED FUEL CONSUMPTION. MANDATORY SEAT BELT LAWS COULD IMPLEMENT THE SAFETY GOAL. THESE POLICIES WOULD ENTAIL ECONOMIC COST, BUT THEY WOULD BE WELL BELOW THE PRESENT TIME COSTS INVOLVED IN THE SPEED LIMIT. EACH POLICY HAS DISTRIBUTIONAL CONSEQUENCES, BUT THESE COULD BE MODIFIED THROUGH INCOME TAX AND RELATED TRANSFERS. THE ARTICLE ILLUSTRATES THE MANY CONSIDERATION IN THE ECONOMIST'S BENEFIT-COST ANALYSIS OF A NATIONWIDE POLICY CHANGE. TABULAR DATA ARE INCLUDED AND AN APPENDIX GIVES CALCUATIONS OF TIME COST AND ENERGY SAVINGS OF THE SPEED LIMIT. SEE NCJ 65332 (AUTHOR ABSTRACT MODIFIED--MJW)