Effects of extraordinary snowfall on traffic safety

Snowfall affects traffic safety by causing changes in roadway surface and visibility that result in crashes, spinouts, and breakdowns. Using data collected at a site that regularly receives nearly 1000 cm of snow during the snow season, this study examines the impact of snowfall quantity, gap between snow events, and weather conditions on crash and incident frequencies. Estimation results from regression analysis show that snowfall severity significantly impacts crashes and incidents but the impact diminishes marginally with each additional centimeter of snow. Gap has a significant fixed effect on crashes but its impact on incidents varies significantly across observations. The effect of the mixed precipitation condition is smaller in comparison to an all-snow condition. These results will help inform policy for snow removal and traffic enforcement in areas of high snowfall.