The federal government collect revenues from taxes paid by highway users, mostly from those levied on gasoline and diesel fuel, and credits them to the Highway Trust Fund. Those revenues and others are subsequently used for federal spending on highways and transit. In fiscal year 2010, the trust fund's revenues totalled about $35 billion. Some policymakers and transportation analysts have expressed interest in developing new sources of funding. This book analyses the effects of alternative approaches to funding highways and compares the effects of current fuel taxes and of possible new taxes on the number of miles highway users drive.