Several Members of Congress and public interest groups have recently proposed policies that would reduce gasoline consumption in the United States. Such proposals stem primarily from a desire to enhance the nation's energy security and to decrease its emissions of carbon dioxide, a key greenhouse gas that affects the Earth's climate. This book compares three methods of reducing gasoline consumption: increasing the corporate average fuel economy (CAFE) standards that govern passenger vehicles, raising the federal tax on gasoline, and setting a limit on carbon emissions from gasoline combustion and requiring gasoline producers to hold allowances for those emissions (a policy known as a cap-and-trade program). Also, the book weighs the relative merits of those policies against several major criteria: whether they would minimise costs to producers and consumers; how reliably they would achieve a given reduction in gasoline use; their implications for automobile safety; and their effects on such factors as traffic congestion, requirements for highway construction, and emissions of air pollutants other than carbon dioxide. In addition, the book examines two more policy implications that lawmakers may be concerned about: the impact on people at different income levels and in different regions, and the effects on federal revenue.