A randomized crossover study of 26 healthy participants measured on-road lane control after vaporized cannabis. THC-dominant and THC/CBD-equivalent products increased standard deviation of lateral position relative to placebo at 40–100 minutes, but not at 240–300 minutes. CBD-dominant cannabis did not show a statistically significant difference from placebo in the tested conditions. These observations should not be generalized to all doses, products, drivers, or routes of administration.
This research describes specific experimental conditions. It does not establish an individual driver’s impairment or the cause of an observed clinical finding without case-specific information. Analytical methodology, timing, dose, route of administration, and plausible alternative explanations should be assessed before making a forensic inference.