Among 2,095 older drivers aged 65-79, past-year cannabis users had 58% more traffic stops but no statistically significant increase in motor vehicle crashes.
Geriatric medicine providers, traffic safety researchers, cannabis policy analysts
58% more traffic stops but no significant crash increase among cannabis-using older drivers
What the researchers found
Of 2,095 active drivers aged 65-79, 186 (8.9%) used cannabis in the past year. After adjusting for demographics and mental health, cannabis use was associated with significantly more traffic stops (aPR=1.58, 95% CI 1.06-2.35, p=0.024) but the association with motor vehicle crashes did not reach significance (p=0.086). Most older cannabis users reported rarely driving immediately after use.
Why it matters
As cannabis legalization expands and the population ages, understanding how cannabis affects older drivers fills a critical safety gap, since most cannabis-driving research has focused on younger populations.
The numbers in context
2,095 older drivers; 186 (8.9%) used cannabis; traffic stops aPR=1.58 (95% CI 1.06-2.35); MVC association p=0.086; multi-center study
How the study worked
Cross-sectional analysis from the AAA LongROAD multi-center study of active drivers aged 65-79. Self-reported cannabis use, motor vehicle crashes, and traffic stops in the past 12 months were collected through participant interviews. Log-binomial regression adjusted for site, demographics, and mental health.
What this study cannot tell us
Cross-sectional design. Self-reported cannabis use and crash data. Past-year cannabis use does not capture timing relative to driving. Relatively few cannabis users in the sample limits statistical power for crash analysis.
How to read the evidence
Multi-center study with adjusted models from a well-established driving safety cohort, but cross-sectional design and self-reported data limit conclusions.
When this study was published
Published 2023
The bigger picture
The disconnect between increased traffic stops and non-significant crash increases may reflect subtle driving impairments detectable by police but insufficient to cause crashes, or it may indicate that older adults who use cannabis drive more cautiously.
Questions still open
- Are traffic stops a valid proxy for impaired driving performance? Would objective driving assessments reveal cannabis-related impairments not captured by crash data?
Common questions
Does cannabis use affect driving in older adults?
How common is cannabis use among older drivers?
Read the original research
Associations of cannabis use with motor vehicle crashes and traffic stops among older drivers: AAA LongROAD study.
Traffic injury prevention, 24(4), 307-314
Citation
Davis, Shelby; Betz, Marian E; Hill, Linda L; Eby, David W; Jones, Vanya C; Mielenz, Thelma J; Molnar, Lisa J; Strogatz, David; Clancy, Kate; Li, Guohua; DiGuiseppi, Carolyn G. (2023). Associations of cannabis use with motor vehicle crashes and traffic stops among older drivers: AAA LongROAD study.. Traffic injury prevention, 24(4), 307-314. https://doi.org/10.1080/15389588.2023.2180736