"TRB Special Report 253 - National Automated Highway System Research Program: A Review" assesses the appropriateness of the original vision and mission of the National Automated Highway System Research Program, the National Automated Highway System Consortium's (NAHSC's) results and the effectiveness of the approach taken by NAHSC in carrying out its charge, and the role of the consortium in future research on intelligent vehicles. Perhaps the most ambitious ITS concept advanced in ISTEA was the proposed development of automated highways. Automated highways were envisioned as increasing throughput dramatically while simultaneously reducing crashes. In ISTEA, Congress challenged USDOT to create, test, and select a prototype automated highway system within 7 years. To this end, a publicprivate consortium was formed to develop and test automation concepts. Those concepts were demonstrated in San Diego, California, in 1997. Although the demonstration showcased some exciting technologies, the committee that reviewed the national automated highway research program found that daunting technical, social, and institutional issues would have to be addressed before such a system could become a reality in any metropolitan area. For example, although the demonstrated technologies would enable remarkably high throughput on high-volume urban Interstates feeding into the heart of a congested urban area, they could not resolve the complex problem of allocating these increased traffic volumes safely and efficiently into the traffic streams of already congested local streets. Even so, the committee urged USDOT to continue to explore the potential for using automation in specific circumstances, as well as the possibilities for developing vehicle-based safety-enhancing technologies for cars, trucks, and transit vehicles.