Among 424 Connecticut cannabis users, more frequent users reported less driving impairment and shorter wait times before driving, with a plurality not waiting at all, and perceived impairment did not predict waiting behavior.
People who drive after cannabis use and policymakers designing drugged driving interventions
Knowledge of impairment did not increase wait time
What the researchers found
Cannabis use frequency predicted both lower self-reported driving impairment and shorter wait time before driving. A plurality of participants reported not waiting at all before driving after cannabis use. Importantly, perceiving that cannabis impaired driving did not predict longer wait times, suggesting knowledge of impairment does not translate to safer behavior.
Why it matters
The disconnect between perceived impairment and driving behavior is concerning. Even people who acknowledge cannabis affects their driving are not waiting longer, suggesting that awareness campaigns alone may not be enough to change behavior.
The numbers in context
424 cannabis users in Connecticut; more frequent users reported less impairment; more frequent users waited less time; plurality reported not waiting at all; perceived impairment did not predict wait time
How the study worked
Cross-sectional survey of 424 cannabis users over age 18 in Connecticut. Purposive sampling used to recruit cannabis users. Measured cannabis use frequency, self-reported impact on driving ability, and time waited before driving after use.
What this study cannot tell us
Self-reported data may not reflect actual driving behavior. Connecticut-specific sample may not generalize. Cross-sectional design cannot establish causation. Frequent users may have developed tolerance, making their self-reports of lower impairment partially accurate.
How to read the evidence
Reasonably sized survey with important findings about behavior-perception gap, but self-reported data and single-state sample
When this study was published
2023 study
The bigger picture
This study challenges the assumption that educating people about cannabis impairment will lead to safer driving behavior. Policy approaches may need to focus on enforcement and objective impairment measures rather than relying on user self-regulation.
Questions still open
- Why does perceived impairment not change driving behavior? Would objective impairment feedback (like an app test) change wait times? Does tolerance in frequent users actually reduce driving impairment?
Common questions
How long do people wait to drive after using cannabis?
Do frequent cannabis users actually drive better than occasional users after use?
Read the original research
Self-reported impacts of recreational and medicinal cannabis use on driving ability and amount of wait time before driving.
Traffic injury prevention, 24(3), 237-241
Citation
Auguste, M E; Zambrano, V C. (2023). Self-reported impacts of recreational and medicinal cannabis use on driving ability and amount of wait time before driving.. Traffic injury prevention, 24(3), 237-241. https://doi.org/10.1080/15389588.2023.2172679