TRB Special Report 360 Managing Highway Stormwater Quality: Driving Progress focuses on engineering and infrastructure strategies to support state DOT decision-making regarding stormwater management approaches to comply with regulations.

Administered by the U.S. Environmental Protection Agency (EPA), state permitting authorities identify each water body that does not meet a water quality standard due to pollutants.

Acknowledging the difference in pollutants that originate from highways through traffic (such as tire and brake wear contaminants) and pollutants that do not originate from highways but are conveyed to water bodies (such as nutrients and bacteria from adjacent land uses) may improve source control.

The report stresses updated modeling options that account for different land uses and are validated with representative empirical monitoring data. Participation in watershed-scale alternative approaches for managing highway stormwater may also result in practical and desirable outcomes.

The report also identifies areas for collaboration between state DOTs, the EPA, and FHWA officials along with state environmental authorities. These partnerships could result in improved stormwater design, construction, and maintenance procedures and guidance. Furthermore, engagement between the agencies early in the process, and longer opportunities for public participation can account for concerns specific to different parts of a watershed to more holistically manage pollutants.

Read the Report