"The groundwork of all happiness is health." - Leigh Hunt

Study: Number of traffic accidents increased after legalization of marijuana

September 7, 2023 – A brand new study shows that the legalization of marijuana for recreational use in Canada in 2018 was linked to a dramatic increase in marijuana-related traffic accidents requiring emergency room treatment.

The researchers found that the most important increases occurred when more sorts of marijuana products became available and were offered by more corporations. For comparison, the researchers checked out alcohol-related traffic crashes and located that there was no corresponding increase in emergency room visits throughout the same time period.

The results, published Wednesday in JAMA network open, suggest “that the legalization of cannabis has played an important role in the increasing rates,” said lead writer Daniel Myran, MD, MPH, in a Press releaseMyran is a family physician and Fellow of the Canadian Institutes for Health Research.

For the study, researchers analyzed data on traffic-related injuries treated in emergency rooms within the Canadian province of Ontario. With greater than 14 million residents, that is probably the most populous province within the country. The study period was from January 2010 to December 2021. Traffic crashes included injuries involving motorized vehicles or pedestrians and cyclists. Marijuana was considered a contributing factor if a medical code for marijuana use was listed within the patient's record.

During the 12-year study period, 426 marijuana-related traffic accidents were treated in emergency departments. The rate of marijuana-related injuries increased from 0.18 emergency room visits per 1,000 automotive accidents in 2010 to 1.01 visits per 1,000 accidents in 2021, a 475% increase over the complete study period.

Because the legalization of recreational marijuana in Canada brought a gradual increase in access to the drug, researchers also compared three time periods to see if different levels of access affected the speed of traffic-related emergency department visits related to marijuana use. The time periods compared were the nearly 8-year period before legalization, the early legalization period from October 2018 to March 2020, and the broad commercialization period of legalization from April 2020 to December 2021. They found that:

  • Comparing the period before legalization with the period in the beginning of legalization, the variety of incidents increased by 94%.
  • Comparing the early phase of legalization with the phase of widespread commercialization, the variety of incidents increased by 223%.

The researchers found that the broad commercialization phase overlapped with the onset of the pandemic, resulting in dramatic changes in driving patterns.

Men, people ages 19 to 21, and folks living in lower-income neighborhoods were probably to go to the emergency room for marijuana-related traffic accidents.

Canada has laws limiting the quantity of the drug in an individual's blood that's allowed while driving. The study authors concluded that more education about driving under the influence of marijuana is required within the country, in addition to stronger enforcement.