Over the past several years, gasoline prices have risen well above their historic average. In many parts of the United States, gasoline prices were above $3 per gallon for much of 2007. Although consumers in the past did not respond very much to small fluctuations in the price of gasoline, the recent large increases have led many people to make adjustments, for example, in the way they drive and in the kinds of vehicles they buy. This Congressional Budget Office (CBO) study, prepared at the request of the Ranking Member of the Senate Budget Committee, relates rising gasoline prices to changes in how fast people drive, the volume of highway traffic, and rail transit ridership. It also examines the effects on market shares, fuel economy, and pricing of cars and light trucks purchased over the past several years. With the world-wide price of oil continuing to rise, this book provides an indication of the kinds of adjustments consumers would make if gasoline prices continue to rise, and of the implications of rising gasoline prices for policies that would discourage gasoline consumption and thus limit the growth in carbon dioxide emissions. This book consists of public documents which have been located, gathered, combined, reformatted, and enhanced with a subject index, selectively edited and bound to provide easy access.