Don’t drive high is a sensible message, but ultimately nobody really knows the impact of cannabis on an individual’s ability to be safely in control of a vehicle.
A recent article entitled “Impaired driving and legalization of recreational cannabis” that was published in the Canadian Medical Association Journal serves to highlight the lack of clarity in this area, and to reinforce the message that a lot more research needs to be done.
The authors of the paper, from Montreal’s McGill University, set out to analyze the association between recreational cannabis legalization and fatal motor vehicle collision rates and then to discuss the policy implications.
Their trawl and examination of the data suggest that legalization of recreational cannabis in the United States may be associated with a small but significant increase in fatal motor vehicle collisions and fatalities (if extrapolated to Canada, they estimated it could result in as many as 308 additional driving fatalities annually).
But determining just who is impaired through use of recreational cannabis and having a clear way to measure that impairment (similar to the way that blood alcohol level determines drunk drivers for example) is impossible based on our current knowledge and the complexities of the cannabis plant.
“Although cannabis consumption has the potential to substantially impair psychomotor skills and cognitive functions — reducing performance on critical tracking and divided-attention tasks, slowing reaction time and increasing lane weaving — the influence of cannabis on driving tasks varies by individual, dose and methods of consumption, and time since consumption before driving,” the authors wrote. “Some studies have found associations between cannabis use and impairment of driving — including in driving simulators, closed-course driving and epidemiologic studies — but others have not.”
What’s clear is that the issue of determining just how much cannabis plays a role in impairment is a complex one. While the current study doesn’t bring any definitive answers, it is another piece in the jigsaw towards getting the legal cannabis world one step closer to solving the problem of impaired driving.