Federal funding to build and maintain the nation's highways and bridges comes primarily from highway users through federal fuel taxes. These revenues have eroded due to improvements in vehicle fuel efficiency and other factors contributing to shortfalls in the Highway Trust Fund. Experts have proposed alternative means of raising revenues by charging drivers fees based on their miles travelled. Several states have tested systems that gather vehicle mileage and location data, which has raised privacy concerns. This book examines the benefits and challenges of mileage fee initiatives in the United States and other selected nations, and discusses whether mileage fee rates are necessary to replace and supplement current Highway Trust Fund revenues and the effect these fees would have on users' costs.