At-grade intersection configuration influences on pedestrian exposure to PM2.5

Abstract

This study analyses intersection configuration design elements associated with traffic-related air pollution and ranks the three most effective configurations. An assessment methodology for pedestrians PM2.5 exposure associated with crossing traffic hotspots is presented. The quantitative PM2.5 exposure concentration reduction effects of at-grade intersection design with stretched segment, pedestrian bridge and left-turn prohibition are estimated using a new US Environmental Protection Agency general emissions model: a multi-link dispersion model based on the AERMOD model. The results of the case study show that intersection design using a stretched segment has a reverse effect on pedestrian PM2.5 exposure, while the left-turn prohibition and the pedestrian bridge are environmentally friendly options with lower PM2.5 concentrations. In order of effectiveness, the intersection design types can be listed as pedestrian bridge, left-turn prohibition and stretched segment, based on the pedestrian PM2.5 exposure index. This study proposes guidelines and tools that road/intersection designers and engineers can use for quantifying environmental impacts. It also shows that design configurations have the potential to mitigate air quality impacts from traffic.