At the outset of the 1990s, leading transportation professionals and policy makers jointly determined that the future of transportation is necessarily one in which traffic operations will receive increasing attention, given imminent completion of the massive Interstate Highway System road construction program initiated four decades ago. For the foreseeable future, the focus increasingly will be on ensuring that existing facilities are operated safely and efficiently. As traffic continues to grow, with little increase in available road space, traffic problems are mounting. There is growing interest in electronic devices and systems that can sense traffic conditions in near real-time, communicate current traffic situations to highway facility and fleet operators, including public transit providers; convey travel planning information to travelers both in advance and during trips; enhance fleet dispatch and management capabilities; and enable `non-stop' toll, transit fare, and regulatory transactions. Collectively known as Intelligent Vehicle - Highway Systems (IVHS), these technologies are expected to dramatically alter the future of transportation, as well as create a market opportunity in excess of $200 billion over the next two decades.