Assessing the impact of traffic crashes on near freeway air quality

•The impact of traffic crashes were quantified in terms of near-freeway air quality.•Areas within 1 km radius of the crash location were affected by vehicle emissions.•The result will be useful for deriving various transportation policies to mitigate air pollution.

As interest grows in eco-friendly green transportation systems, transportation management agencies have focused on effectively mitigating vehicle emissions. Extensive research has been conducted to enhance the performance of transportation systems in terms of environmental compatibility. A novel feature of this study includes considering crash occurrences when analyzing near-freeway air quality. This study quantifies the impact of traffic crashes on vehicle emissions and the associated near-freeway air quality. Both crash data and vehicle detection systems (VDS) data, which were obtained in 2012 from a Korean freeway located in a densely populated urban area, were used to determine the impact of traffic crashes on near-freeway air quality. MOVES and CALPUFF were adopted to estimate freeway emissions and air dispersion for crash-involved and crash-free traffic conditions. The contributing factors that affect the severity of emission dispersion were identified by regression analyses. Results show a community near freeways within a 1-km radius of crash locations was affected by traffic-related air pollution exposure. The regression analyses also showed crash characteristics, and weather characteristics affect traffic-related air pollution exposure areas. Finally, this study proposed traffic-related public health strategies to mitigate air pollutants generated from crash occurrences on freeways.