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Study breakdown

One in ten Ontario high school drivers reported driving within an hour of using cannabis

Cross SectionalModerate evidence
The takeaway

Among 1,161 licensed high school students in Ontario, 10.3% reported driving within an hour of cannabis use, with cannabis dependence, low perceived risk, and pro-legalization attitudes as the strongest predictors.

Parents of teen drivers, driving safety educators, policymakers, youth substance use researchers

10.3% of licensed high school students drove within an hour of cannabis use

What the researchers found

Past-year cannabis-impaired driving prevalence was 10.3%. The strongest predictors were probable cannabis dependence (OR=12.7), low perceived risk of cannabis (OR=5.3), pro-legalization attitudes (OR=4.3), and being male (OR=2.6). Cannabis-impaired driving was also correlated with texting while driving and driving after alcohol.

Why it matters

With cannabis now legal in Canada, understanding what drives teen cannabis-impaired driving is essential for designing effective prevention programs, especially since many correlates are attitudinal and potentially modifiable.

The numbers in context

1,161 licensed students; mean age 16.8; 10.3% drove within 1 hour of cannabis use; OR 12.7 for cannabis dependence; OR 5.3 for low perceived risk; OR 4.3 for pro-legalization; OR 2.6 for male

How the study worked

Cross-sectional analysis of 1,161 licensed high school students from the 2017 Ontario Student Health and Drug Use Survey, using multivariable logistic regression.

What this study cannot tell us

Self-reported driving behaviors, cross-sectional design, Ontario-specific findings, 2017 data precedes legalization, licensed students may not represent all teen drivers.

How to read the evidence

Large provincial student health survey with multivariable analysis

When this study was published

Published in 2021 using 2017 data, before cannabis legalization in Canada. Prevalence may have changed since.

The bigger picture

The clustering of cannabis-impaired driving with other risky driving behaviors suggests that prevention programs need to address a broader pattern of risk-taking rather than focusing on cannabis alone.

Questions still open

  • Has legalization changed the prevalence of cannabis-impaired driving among teens? Would changing perceptions of cannabis risk through education reduce impaired driving? Are different intervention approaches needed for dependent vs casual users?

Common questions

How common is cannabis-impaired driving among teens?
In this Ontario survey, 10.3% of licensed high school students reported driving within an hour of using cannabis in the past year.
What predicts teen cannabis-impaired driving?
The strongest predictor was probable cannabis dependence (12.7 times the odds), followed by low perceived risk of cannabis, pro-legalization attitudes, and being male. These teens also tended to text while driving and drive after drinking.

Read the original research

Correlates of driving after cannabis use in high school students.

Preventive medicine, 150, 106667

Citation

Cantor, Nathan; Kingsbury, Mila; Hamilton, Hayley A; Wild, T Cameron; Owusu-Bempah, Akwasi; Colman, Ian. (2021). Correlates of driving after cannabis use in high school students.. Preventive medicine, 150, 106667. https://doi.org/10.1016/j.ypmed.2021.106667