Local, regional, and state agencies in California are making efforts to increase bicycle infrastructure and ridership. In most areas, bicycle routes are a subset of vehicle routes and new bicycle infrastructure is created by adding bicycle lane(s) to existing roadways. The planning process for identifying bicycle routes typically considers available right-of-way, existing roadway infrastructure (e.g., presence of bridges, number of intersections), vehicular traffic volume, safety concerns, and built environment factors (e.g., attractive land uses such as shopping districts, scenic views), among other factors. However, exposure to traffic-related air pollution is rarely considered in this process. This oversight can have negative impacts on bicyclists given they are directly exposed to vehicular exhaust and experience an increased breathing rate during biking. Exposure to traffic-related air pollution has been proven to contribute to a wide range of health problems such as lung and heart diseases.
