Effects of heat waves on traffic collisions: A case study in Alabama, United States

Keywords: Climate change, Heat waves, Traffic collisions, Alabama heat, Case-crossover design, Traffic safety
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 02:00 PM (Eastern Time (US & Canada)) - 2/25/2022 03:20 PM (Eastern Time (US & Canada))
Room: Virtual 6

Abstract

Did heat waves cause traffic collisions? Did the relationship change if all traffic collisions instead of fatal traffic collisions were included? We applied a time--stratified case-crossover design to investigate the effects of heat waves on traffic collisions in Alabama, the United States, in May–September from 2009–2018. Meanwhile, a heat wave index, defined as the daily mean temperature >the 95th percentile for ≥ 2 consecutive days, was derived by meteorological data from Phase 2 of the North American Land Data Assimilation System. Traffic collision records in the analysis were obtained from the Alabama Department of Transportation. In the results, we found a nonsignificant and negative association between traffic collisions and heat waves with a 1.4% decrease [95% confidence interval (CI): −3.1%, 0.4%] in traffic collisions on heat wave days compared with non–heat wave days. We had similar findings when we stratified the analysis by driver-related factors (i.e., gender, age, race, employment status, and driver residence distances), vehicle-related factor (i.e., vehicle usage), and collision-related factors (i.e., rural/urban roads, speed limits, and intersections), respectively. However, our results show a significant and positive association on heat wave days without precipitation [23.5% increase (95% CI: 7.3%, 42.3%)]. In conclusion, traffic collisions were not associated with heat waves in many collision-related conditions in Alabama.