People were willing to buy and use more cannabis when they had more time before they needed to drive
Using behavioral economics tasks, cannabis users adjusted their hypothetical purchasing and consumption downward as driving became more imminent, but those who perceived less danger from cannabis-impaired driving consumed more across all conditions.
Quick Facts
What This Study Found
Cannabis demand (how much people would purchase and consume) was sensitive to driving latency: participants consumed more when driving was 6 hours away versus 20 minutes away. Those who perceived driving after cannabis as less dangerous showed higher cannabis demand across all conditions. The effects were statistically significant but small in magnitude.
Key Numbers
167 participants. Significant main effects of driving latency on all demand indices (p < 0.05, partial eta-squared = 0.008-0.043). Perceived dangerousness inversely correlated with demand (r = -0.29 to -0.62).
How They Did This
Cross-sectional online study of 167 adults who smoked cannabis at least monthly (77% White, 45% women, mean age 38.55). Participants completed four marijuana purchase tasks under different driving latency vignettes (no driving, 20 minutes, 1 hour, 6 hours). Demand indices included intensity, breakpoint, maximum expenditure, and price sensitivity.
Why This Research Matters
Understanding what factors influence people to use cannabis before driving can inform public safety messaging. The finding that risk perception correlates with behavior suggests education about impairment risks could reduce cannabis-impaired driving.
The Bigger Picture
As cannabis legalization expands, so does the challenge of impaired driving. This study adds to the small literature showing that people do moderate their cannabis use based on driving plans, but not enough to eliminate risk, especially among those who underestimate the danger.
What This Study Doesn't Tell Us
Hypothetical purchase tasks, not real consumption. Online convenience sample. Mostly White, cannabis-experienced participants. Small effect sizes. Does not capture actual driving behavior.
Questions This Raises
- ?Would real-world studies confirm that driving latency affects actual cannabis consumption?
- ?Could public health campaigns shift perceived dangerousness enough to change behavior?
Trust & Context
- Key Stat:
- Perceived dangerousness of cannabis-impaired driving correlated r = -0.29 to -0.62 with cannabis demand
- Evidence Grade:
- Well-designed behavioral economics study, but hypothetical scenarios and a convenience sample limit real-world applicability.
- Study Age:
- 2026 publication
- Original Title:
- Pass the Keys: Using Behavioral Economics to Explore Driving After Cannabis Use.
- Published In:
- Substance use & addiction journal, 47(1), 134-143 (2026)
- Authors:
- Miller, Brandon P(2), Aston, Elizabeth R(9), Spindle, Tory R(18), Amlung, Michael
- Database ID:
- RTHC-08491
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
What is a marijuana purchase task?
A behavioral economics tool where participants say how much cannabis they would buy and consume at different prices, used to measure demand and motivation for use under different conditions.
Did people stop using cannabis when they had to drive soon?
They used less, but many still indicated they would consume some cannabis even with driving 20 minutes away, especially those who perceived less danger.
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Cite This Study
https://rethinkthc.com/research/RTHC-08491APA
Miller, Brandon P; Aston, Elizabeth R; Spindle, Tory R; Amlung, Michael. (2026). Pass the Keys: Using Behavioral Economics to Explore Driving After Cannabis Use.. Substance use & addiction journal, 47(1), 134-143. https://doi.org/10.1177/29767342251360851
MLA
Miller, Brandon P, et al. "Pass the Keys: Using Behavioral Economics to Explore Driving After Cannabis Use.." Substance use & addiction journal, 2026. https://doi.org/10.1177/29767342251360851
RethinkTHC
RethinkTHC Research Database. "Pass the Keys: Using Behavioral Economics to Explore Driving..." RTHC-08491. Retrieved from https://rethinkthc.com/research/miller-2026-pass-the-keys-using
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.