Cannabis users who feel stimulated rather than stoned show less driving impairment
Drivers who perceived more stimulation from cannabis showed less negative impact on driving, while those who felt more "stoned" or "high" showed greater impairment.
Quick Facts
What This Study Found
Subjective cannabis effects predicted changes in driver inputs (steering frequency, reversal rate), while actual driving performance measures like lane weaving were better predicted by dosing condition. Drivers reporting more stimulation showed better performance, while those feeling more stoned showed worse performance.
Key Numbers
10 subjects; driving measured ~2 hours after inhalation; 6.9% THC vs placebo; subjective measures collected at peak and before driving
How They Did This
Analysis of 10 subjects in a driving simulator study approximately two hours after cannabis inhalation (6.9% THC vs placebo), examining relationships between subjective effects and driving performance using visual analog scales and simulator metrics.
Why This Research Matters
If different subjective experiences from cannabis predict different levels of driving impairment, this could have implications for how we think about cannabis strain effects and impairment testing.
The Bigger Picture
This suggests that different cannabis strains producing different subjective experiences could have varying impacts on driving safety, complicating blanket impairment laws.
What This Study Doesn't Tell Us
Very small sample (10 subjects), single THC potency tested, simulated rather than real-world driving, subjective self-reports may not be reliable measures of actual impairment.
Questions This Raises
- ?Do indica vs sativa strains reliably produce different driving impairment levels?
- ?Could self-reported subjective effects be used as a practical impairment screening tool?
Trust & Context
- Key Stat:
- Stimulation effects were associated with less driving impairment
- Evidence Grade:
- Very small randomized study with only 10 participants using simulated driving
- Study Age:
- Published in 2021. Research on how subjective cannabis effects relate to driving impairment is in early stages.
- Original Title:
- Perceived effects of cannabis and changes in driving performance under the influence of cannabis.
- Published In:
- Traffic injury prevention, 22(sup1), S8-S13 (2021)
- Authors:
- Burt, Thomas S(3), Brown, Timothy L(6), Schmitt, Rose(6), McGehee, Daniel, Milavetz, Gary, Gaffney, Gary R, Berka, Chris
- Database ID:
- RTHC-03036
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Does how cannabis makes you feel predict driving impairment?
In this small study, yes. Drivers who felt more stimulated showed less negative impact on driving, while those who felt more stoned showed greater impairment, suggesting different subjective experiences map to different impairment levels.
Can cannabis users tell if they are too impaired to drive?
Participants could perceive some effects that correlated with changes in their driving inputs, but the actual driving performance measures were better predicted by whether they received cannabis, not by what they felt.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-03036APA
Burt, Thomas S; Brown, Timothy L; Schmitt, Rose; McGehee, Daniel; Milavetz, Gary; Gaffney, Gary R; Berka, Chris. (2021). Perceived effects of cannabis and changes in driving performance under the influence of cannabis.. Traffic injury prevention, 22(sup1), S8-S13. https://doi.org/10.1080/15389588.2021.1933459
MLA
Burt, Thomas S, et al. "Perceived effects of cannabis and changes in driving performance under the influence of cannabis.." Traffic injury prevention, 2021. https://doi.org/10.1080/15389588.2021.1933459
RethinkTHC
RethinkTHC Research Database. "Perceived effects of cannabis and changes in driving perform..." RTHC-03036. Retrieved from https://rethinkthc.com/research/burt-2021-perceived-effects-of-cannabis
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.