New Research Snapshot! Alcohol and marijuana consumption is related to risky driving and passenger behaviours in youth

What you need to know at-a-glance:

After alcohol, cannabis is the second most used substance in Canada. There’s a higher risk of traffic collisions and car-crash deaths among young drivers, aged 16-19. It was reported that a large portion of these fatalities were related to alcohol in 2012.

Evidence shows that many youth engage in risky passenger behaviour such as getting into a car with a driver who has consumed alcohol or cannabis. However, it’s important to note that there is still some debate about whether driving after using cannabis is related to car accidents and deaths.


Download the PDF version of the Research Snapshot. You can also see the infographic we developed for this research.

What is this research about?

Since the Canadian government legalized the sale and possession of cannabis in early October, there’s been some discussion on the risks of driving after using cannabis or being a passenger of a car where the driver has used cannabis.

“Risky driving” is defined as driving under the influence of alcohol or cannabis. It also refers to passenger behaviours, such as the decision to ride in a car with an impaired driver.

This study looked at which individual characteristics or environmental factors contributed to risky driving and risky passenger behaviours of youth in Canada.

What did the researchers do?

From 2014 to 2015, a team of researchers looked at the personal and environmental characteristics of grade 9-12 students living in Canada that are associated with “risky driving.” They administered the Canadian Student Tobacco, Alcohol and Drug Survey to 24,650 students in schools across Canada.

The survey explored situations where individuals were driving under the influence of either alcohol or cannabis, and where individuals were passengers of a driver who was under the influence of either alcohol or cannabis.

It also took into account gender, school grade, province, previous drinking behaviours, race/ethnicity, and school location (urban/rural).

What did the researchers find?

  • Nearly 1 in 10 grade 11-12 students said they have driven after drinking alcohol or using cannabis.
  • 35% of grade 9-12 students stated they were passengers of a driver who had drunk within the hour; 20% stated being passengers of a driver who had used cannabis within the past two hours.
  • Boys were more likely to drive after drinking or using cannabis. Girls, on the other hand, were more likely to be a passenger of a driver who had recently been drinking. 
  • Older youth were more likely to drive while impaired as well as ride as a passenger with an impaired driver.
  • Students living in rural areas were more likely to engage in risky driving.

How can you use this research?

This study may be useful when considering policy and legislation across Canada as a precautionary measure for youth engaging in risky driving and risky passenger behaviours. With cannabis being legalized, it’s important to consider the risks that may be associated with cannabis use and impaired driving. Further research should look at how provincial policies impact driving behaviours.

Limitations and next steps

  • The survey results were based off of self-reported data. It’s likely there has been some underreporting, where individuals chose not to disclose information.
  • Additionally, while the number of car accidents related to impaired driving can be objectively measured, there really is no data on drinking or cannabis use prior to driving.
  • Survey questions did not assess impairment level, which differs across individuals and on the amount of alcohol or cannabis consumed.
  • The survey did not include youth from Canada’s territories, where the prevalence of impaired driving is much higher.
  • Lastly, the survey did not assess if students had driver’s licences. It would be more likely that results depicting students engaging in risky driving behaviour would be higher if the survey only looked at students with driver’s licenses.

About the researchers

Leia Minaker1, Aaron Bonham1, Tara Elton-Marshall2,3,4, Cesar Leos-Toro1, T. Cameron Wild4, David Hammond1

1 University of Waterloo, Waterloo, ON.

2 Institute of Mental Health Policy Research, CAMH, London, ON.

3 University of Toronto, Toronto, ON.

4 University of Alberta, Edmonton, AB.


Cannabis, marijuana, youth, impaired driving, drugs, alcohol


This Research Snapshot is based on their article, “Under the influence: examination of prevalence and correlates of alcohol and marijuana consumption in relation to youth driving and passenger behaviours in Canada. A cross-sectional study,” which was published in the Canadian Medical Association Journal Open, CMAJ Open 2017. DOI:10.9778/cmaj.20160168