Motor vehicle collisions exact a significant toll on Canadians each year-2,917 deaths and 227,500 injuries in 2000 alone¹. Weather influences collision rates primarily by reducing visibility and road surface friction. A small but growing literature suggests that precipitation generally increases collision risk by about 50 to 100 percent. This paper presents findings from an empirical analysis of weather-related injury collision risk for several Canadian cities and various weather scenarios. Estimated risks for weather conditions are compared with published health risks associated with other atmospheric hazards, including heat stress, air pollution and extreme weather events. Methodological issues and examples of interventions used to reduce the risk for each hazard are also discussed.

¹Transport Canada, 2001