An important benefit of ITS is diminished traffic congestion through improved management of accidents and other traffic incidents, which together account for some half of all congestion on U.S. roads. Successful application of available ITS technologies requires an improved understanding of the causes of accidents, and proper coordination among relevant transportation and public safety agencies. George Mason's Transportation Policy Program is involved both in the analysis of incident causes and in the promotion of improved institutional mechanisms for managing incidents. The study notes, optimistically, that, while the Beltway is operating at twice its design capacity, its accident rate decreased during the three-year period of the study. TPP's analysis examined accident data from 1990to 1992.
Most fatal crashes occur during nighttime hours.
Rear-end collisions, which occur mostly during congested rush hours, account for more than 50 percent of all accidents on the Virginia portion of the Beltway and 40 percent on the Maryland portion. In a period of diverse experimentation with new technologies and operational tests, it is essential to develop standards of evaluation that are meaningful to ITS researchers and practitioners throughout the country. Such evaluations must address not just the technical capacity of new systems, but a host of related issues, including financial cost, ease of deployment and maintenance, burden on deploying organizations, impact on the nation's overall transportation system, and contributions to broader societal goals, such as improved air quality and enhanced mobility for all citizens. Building on its strong tradition in evaluative studies, the Transportation Policy Program is now focusing on evaluation of regional intelligent transportation systems. In a companion study, the authors apply this approach to the FAST-TOLL electronic toll collection system, currently being installed on Northern Virginia's Dulles Toll Road and on the Dulles Greenway, the largest privatized interstate class highway in the United States.