Since the early 1970s our Nation has been experiencing a growing awareness of the complex relationships between the transportation infrastructure and environmental quality. One notable concern has been the potential for water quality degradation as a result of stormwater runoff over paved highway surfaces. Laws, executive orders, and government polices designed to minimize and mitigate the potential negative consequences of highway runoff have been enacted. These include the National Environmental Policy Act, the Intermodal Surface Transportation Efficiency Act, the Coastal Zone Reauthorization Amendment, the National Wild and Scenic Rivers Act, and the Clean Water Act of 1972, as amended, including the National Pollutant Discharge Elimination System and the Nonpoint Source Management Programs. The Federal Highway Administration (FHWA) has designated environmental protection and enhancement are high-priority program areas that stress the evaluation of highway-related water quality impacts, as well as avoiding, mitigating, or managing such impacts, and coordinating with other agencies to ensure that Federal environmental policies are placed in perspective with other primary highway missions. The FHWA, the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA) are currently cooperating on research and development projects related to the minimization of water quality impacts from highway runoff.