‘Very large increase’ in weed-related traffic injuries since legalization: study

Over a span of 11 years, annual rates of Ontario emergency department visits for cannabis-related traffic injuries have surged 475 per cent, according to a recent study.

Over a span of 11 years, annual rates of Ontario emergency department visits for cannabis-related traffic injuries surged dramatically, according to a recent study from The Ottawa Hospital.

The study, published Wednesday in JAMA Network Open, looked at cannabis involvement in emergency room visits for traffic injuries between 2010 and 2021 in Ontario. It also examined shifts in cannabis consumption and driving habits following federal legalization in 2018.

“Our data is raising concern about a growing problem of cannabis impairment and severe road injuries,” said lead author, Dr. Daniel Myran, who is also a fellow at the Bruyère Research Institute and with the University of Ottawa’s Department of Family Medicine.

“Since 2010 there has been a very, very large increase in cannabis involvement and traffic injury visits in Ontario.”

The study also found sharper spikes of marijuana involvement in traffic-injury emergency visits following legalization, he added.

On Oct. 17, 2018, marijuana was legalized in Canada. A 2020 Statistics Canada report found that the legalization of cannabis was associated with an increase in overall consumption, especially among people aged 25 and older. And with legalization came amendments to impaired driving laws in the country, adding limits on blood tetrahydrocannabinol (THC) levels.

This is because cannabis can impair the cognitive and motor abilities necessary to operate a vehicle and doubles the risk of crash involvement, according to the Canadian Centre on Substance Use and Addiction.

With the rise in cannabis use over the years, Myran and his research team wanted to find out if there were shifts in cannabis-impaired driving.