This study examines public policy, privacy, and institutional issues related to a new road user charge system. This system has been viewed as a possible replacement for existing motor fuel taxes. The adequacy of motor fuel taxes is a national issue, as the federal government and all states rely heavily on today's fuel-based user charges to finance transportation projects. With new vehicle propulsion technologies on the horizon, in particular hybrid gas-electric engines and hydrogen fuel cells, there is a realization that transportation revenue collected from motor fuel taxes may eventually be in serious jeopardy. The authors conclude that the best method for assessing road user charges is on an actual miles traveled basis, also called a vehicle miles of travel (VMT) user charge. A VMT charge, coupled with intelligent vehicle technology and Global Positioning Systems (GPS) technology, would provide a means for crediting states or sub-state jurisdictions for the miles of travel occurring within their boundaries. Data would be stored on the vehicle and downloaded to a collection center at various times. The researchers conclude that a system can be designed that is convenient, ensures low evasion rates, is efficient to administer, and ensures user privacy. The concept has the potential to ensure a stable stream of revenue for the highway system, as well as being equitable, convenient, and flexible in its application. This system may allow for varying user charges by jurisdiction, class of vehicle, type of facility, or time of day. However, the authors caution that trying to accomplish all of these purposes could greatly complicate implementation, at least initially. The authors recommend a systematic field test and demonstration including the equipment of a substantial number of vehicles to validate system technology, reliability, and security and to assess user satisfaction and acceptance.