A new study has found that drivers who consumed Delta-9-tetrahydrocannabinol (THC) compensated for their impairment by driving more cautiously, specifically by slowing their speed and increasing their following distance from other vehicles. The research, published in the journal Psychopharmacology, offers new insights as states grapple with determining legal THC limits for drivers.
The study assessed the simulated driving performance of 43 medical cannabis patients before and after they consumed their prescribed THC oils. Researchers looked at hazard perception and risk-taking behaviors, including speeding propensity, following distance, and gap acceptance at intersections.
The key findings suggest that while participants drove more slowly and left more space, their actual hazard perception skills did not significantly decline. However, a crucial disconnect was observed: most participants believed their performance had declined, rating their own abilities as lower after consumption. This indicates that cannabis users may be unable to accurately self-assess their ability to handle complex traffic scenarios, even if they are attempting to drive more cautiously.
The study's authors noted several limitations, including that all participants were active medical cannabis patients and may have had unusually high tolerances to THC. The dosage also varied as participants consumed their regular prescription dose. Despite these limitations, the study provides important preliminary findings on how THC oil affects driving performance, warranting further research to better understand the impact of cannabis on road safety.