A randomized clinical trial found that standard field sobriety tests had limited effectiveness in identifying cannabis-impaired drivers compared to their use for alcohol impairment.
Law enforcement, traffic safety researchers, defense attorneys, policymakers, and cannabis consumers.
Limited FST accuracyStandard field sobriety tests showed limited sensitivity for identifying THC-impaired drivers
What the researchers found
Field sobriety tests, the gold standard for alcohol-impaired driving detection, showed limited sensitivity and specificity for identifying THC-impaired drivers, highlighting the need for cannabis-specific impairment evaluation tools.
Why it matters
As cannabis legalization expands, law enforcement relies on field sobriety tests designed for alcohol to detect cannabis impairment. This RCT provides evidence on whether that approach is scientifically valid.
The numbers in context
The randomized clinical trial evaluated standard field sobriety tests for detecting THC impairment with increasing cannabis legalization.
How the study worked
Randomized clinical trial administering cannabis or placebo and evaluating field sobriety test performance.
Who was studied
Participants randomized to cannabis or placebo and evaluated using field sobriety tests.
What this study cannot tell us
Controlled dosing may not reflect real-world cannabis consumption patterns; FSTs may be affected by factors unrelated to impairment; single-dose design.
How to read the evidence
Randomized clinical trial provides strong evidence; gold standard study design for this question.
When this study was published
Recent RCT addressing a critical gap in cannabis-impaired driving evidence.
The bigger picture
This RCT provides crucial evidence for the legal and policy debate about cannabis-impaired driving enforcement, potentially influencing how courts and legislators approach DUI cannabis cases.
Replication
Among the first RCTs to formally evaluate FSTs for cannabis; findings consistent with observational studies.
Funding
Not specified
Conflicts of interest
Not specified
Questions still open
- Which FST components are most sensitive to cannabis?
- Should new cannabis-specific tests be developed?
- How does tolerance affect FST performance?
Read the original research
Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis: A Randomized Clinical Trial.
JAMA psychiatry, 80(9), 914-923
Citation
Marcotte, Thomas D; Umlauf, Anya; Grelotti, David J; Sones, Emily G; Mastropietro, Kyle F; Suhandynata, Raymond T; Huestis, Marilyn A; Grant, Igor; Fitzgerald, Robert L. (2023). Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis: A Randomized Clinical Trial.. JAMA psychiatry, 80(9), 914-923. https://doi.org/10.1001/jamapsychiatry.2023.2345