Exploring the role of cannabis in fatal car crashes and a survey of Canadians’ beliefs, cannabis use behaviours and decision-making processes related to cannabis and driving

Abstract

This mixed-method research project involved two phases investigating relationships between cannabis use and driving. The first phase utilized data from the Fatality Analysis Reporting System (FARS) to determine how much the odds of being responsible for a fatal car crash increased when the driver was under the influence of cannabis. A total of 242,942 fatal crashes met criteria for inclusion. Logistic regression analyses indicated that the presence of THC increased the odds of engaging in unsafe driver actions by 29%. Three driver actions were significantly associated with cannabis use: failure to keep in proper lane, driving too fast for conditions or over the speed limit, and operating the vehicle in an erratic, careless, negligent, reckless manner. Phase two involved developing a new survey to assess Canadians’ knowledge, beliefs and behaviour about cannabis products and driving. This new survey expanded on the existing Canadian Cannabis Survey (CCS), addressing gaps, and adding novel components. After the preliminary survey was developed, three focus groups were conducted. As a result, additional questions and response options were added. [...]