The impact of provincial cannabis policy on impaired driving.

Impaired driving is a major public health problem. Alcohol impaired driving is involved in a third of fatal crashes in Canada, and has been well studied. Other drugs such as cannabis, cocaine, and some medications also cause impairment and may contribute to crashes. Now that cannabis is legalized there is concern that the number of cannabis-related car crashes will increase. The provinces have different strategies on how to prevent cannabis impaired driving. We propose to evaluate the impact of provincial cannabis policy on the rates of driving after using cannabis (and other drugs). In collaboration with government officials we will evaluate cannabis policies from British Columbia and Ontario. Our primary objective is to compare how often drivers from BC and ON who were involved in a car crash test positive for cannabis, alcohol and other drugs. We will compare these rates with the rate of positive drug tests in injured passengers. If cannabis policy deters people from driving after using cannabis, we would expect to find lower rates of drug use in drivers than in passengers. We will work with provincial and national injury prevention groups and road safety policy makers. We will provide them with reports. Our aim is to provide data that will help policy makers and injury prevention groups prevent impaired driving.