Active transportation modes such as walking and biking are key elements of sustainable transportation systems. In order to promote biking as an alternative form of transportation, a holistic approach to improving the quality of the biking experience is needed. Local, regional, and state agencies in California are making efforts to increase bicycle infrastructure in the State in order to promote sustainable and multi-modal transportation. In most areas, bicycle routes are a subset of vehicle routes and new bicycle infrastructure is created by adding bicycle lane(s) to existing rights-of-way. The planning of bicycle routes typically takes into consideration available right-of-way, existing roadway infrastructure, vehicular traffic volume, safety concern, and built environment, among others. Exposure to traffic-related air pollution, on the other hand, is rarely considered in route planning, despite bicyclists being vulnerable to the harmful air pollution due to their direct exposure to vehicular exhaust and increased breathing rate during biking. Traffic volume alone is not a sufficient surrogate for the level of air pollution on the road, though; it also depends on traffic speed, fleet mix, meteorology condition (e.g., wind speed and wind direction), and terrain.
This research explores how exposure to traffic-related air pollution can be included as a consideration when conducting bicycle route planning. Specifically, this research explores: 1) creating a streamlined process for estimating the level of near-road air pollution concentration; 2) developing a novel bicycle route planning tool that allows planners and engineers to compare the exposure of bicyclists to traffic-related air pollution among different bicycle routes; and 3) demonstrating the method for considering bicyclists’ exposure to traffic-related air pollution in bicycle route planning.