Many California Cannabis Users Unsure About Driving Laws Six Years After Legalization
Six years after California legalized recreational cannabis, only 62% of users knew passengers cannot consume cannabis in a moving vehicle, and 13% said legalization made them more likely to drive under the influence.
Quick Facts
What This Study Found
Among 4,020 current cannabis users in California, 62% knew about the in-vehicle consumption ban, 59% knew containers must be sealed, and 74% knew DUIC citations are possible. 64% felt safe driving within 3 hours of inhaling cannabis. Lower regulatory knowledge was associated with more adverse driving outcomes.
Key Numbers
62% knew about in-vehicle consumption ban. 59% knew about sealed container requirement. 74% knew about DUIC citations. 64% felt safe driving within 3 hours of inhaling. 55% felt safe within 5 hours of edibles. 13% said legalization increased their likelihood of DUIC.
How They Did This
Large survey of 15,208 participants demographically matched to the 2020 California census. A subset of 4,020 current users, 523 former users, and 635 never-users completed detailed questionnaires about driving knowledge, attitudes, and behaviors. Chi-square analysis was used for descriptive analysis.
Why This Research Matters
Mixed awareness of cannabis driving laws years after legalization suggests that regulatory knowledge gaps persist and may contribute to impaired driving. The association between lower knowledge and worse driving outcomes points to an actionable public health target.
The Bigger Picture
Cannabis legalization without adequate public education about driving regulations may leave gaps that contribute to impaired driving. The finding that knowledge predicts driving outcomes suggests that education campaigns could reduce harm.
What This Study Doesn't Tell Us
Self-reported data on driving behaviors and knowledge. California-specific results may not generalize. The survey cannot establish causation between knowledge gaps and driving outcomes.
Questions This Raises
- ?What types of public education campaigns most effectively improve cannabis driving knowledge?
- ?How does actual impairment duration compare to when users feel safe to drive?
Trust & Context
- Key Stat:
- 13% said legalization increased their likelihood of driving under the influence
- Evidence Grade:
- Moderate: large census-matched survey with detailed questionnaire, but self-reported data and cross-sectional design
- Study Age:
- Published in 2025 surveying Californians after 2018 legalization
- Original Title:
- Driving and cannabis use: a questionnaire about knowledge and behaviors after the legalization of recreational cannabis in California.
- Published In:
- BMC public health, 25(1), 3219 (2025)
- Authors:
- Baird, Sara(4), Ageze, Daniel(4), Hill, Linda L(3), Hacker, Sarah, Dell'Acqua, Renee, Gold, Alice, Lanin-Kettering, Ilene, Shaughnessy, Tom, Marcotte, Thomas D
- Database ID:
- RTHC-06001
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
How long should you wait to drive after using cannabis?
This study found 64% of users felt safe driving within 3 hours of inhaling cannabis, but the study did not measure actual impairment. Research on cannabis impairment duration varies widely and depends on dose, tolerance, and individual factors.
Did legalization change driving behavior?
13% of current cannabis users reported that Proposition 64 increased their likelihood of driving under the influence. Those with less knowledge of driving-related regulations were more likely to report adverse driving outcomes.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-06001APA
Baird, Sara; Ageze, Daniel; Hill, Linda L; Hacker, Sarah; Dell'Acqua, Renee; Gold, Alice; Lanin-Kettering, Ilene; Shaughnessy, Tom; Marcotte, Thomas D. (2025). Driving and cannabis use: a questionnaire about knowledge and behaviors after the legalization of recreational cannabis in California.. BMC public health, 25(1), 3219. https://doi.org/10.1186/s12889-025-24309-4
MLA
Baird, Sara, et al. "Driving and cannabis use: a questionnaire about knowledge and behaviors after the legalization of recreational cannabis in California.." BMC public health, 2025. https://doi.org/10.1186/s12889-025-24309-4
RethinkTHC
RethinkTHC Research Database. "Driving and cannabis use: a questionnaire about knowledge an..." RTHC-06001. Retrieved from https://rethinkthc.com/research/baird-2025-driving-and-cannabis-use
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.