Between 1999 and 2000, the National Transportation Safety Board investigated nine rear-end collisions in which 20 people died and 181 were injured. Common to all nine accidents was the rear following vehicle driver's degraded perception of traffic conditions ahead. As the Safety Board reported in 1995 and further discussed at its 1999 public hearing, existing technology in the form of intelligent Transportation Systems can prevent rear-end collisions. In the nine accidents investigated by the Board, one (and sometimes more) of the available technologies would have helped alert drivers to the vehicles ahead, so that they could slow their vehicles, and would have prevented or mitigated the circumstances of the collisions. The major issue addressed in this Safety Board special investigation report is the prevention of rear-end collisions through the use of Intelligent transportation systems. This report also discusses some of the challenges, including implementation, consumer acceptance, public perception, and training, associated with the deployment of vehicle-and infrastructure-based collision warning systems. As a result of its investigation, the Safety Board issues recommendations to the U.S. Department of Transportation; the Federal Highway Administration; the National Highway Traffic Safety Administration; truck, motorcoach, and automobile manufacturers; the Intelligent Transportation Society of America; the American Trucking Associations, Inc.; the Owner-Operator Independent Driver Association; and the National Private Truck Council.

The General Accounting Office (GAO) examined the development and application of intelligent vehicle and highway systems (IVHS), more commonly known as smart highways, as a means of reducing traffic congestion. The following questions were addressed: What have the major studies concluded about the potential effects of IVHS, and to what extent are these findings empirically based? What additional information can be learned from IVHS field tests under way? What major obstacles could impede the realization of transportation benefits possible through IVHS technologies? In brief, GAO found that the empirical basis for judging the effects of IVHS is limited but nonetheless positive and promising.