"The groundwork of all happiness is health." - Leigh Hunt

Smoking cannabis impairs driving for longer than you’re thinking that

February 5, 2024 – Recreational marijuana is now legal in greater than 20 states, which could mean more marijuana users are wondering how quickly they’ll safely drive again after getting high.

Studies from the Center for Medicinal Cannabis Research on the University of California, San Diego show that individuals should wait about 4.5 hours after smoking a joint before getting behind the wheel. The Wall Street Journal reported.

However, many study participants incorrectly assumed that they’d have the option to drive safely much sooner.

In the study published in JAMA PsychiatryAbout 200 cannabis users smoked either THC or a placebo after which drove in a automobile simulator. About half of THC users showed impaired driving in comparison with the placebo group.

“While the THC group generally reported feeling impaired and hesitant while driving after 30 minutes, participants rated themselves as increasingly confident while driving after 1 hour and 30 minutes, whereas simulator data suggested sustained reduced driving performance, including a higher likelihood of leaving the lane,” the study said. “Although performance improved 3.5 hours after smoking, full recovery was not seen until 4.5 hours after smoking.”

“Even people who are very conscientious and say, 'I don't drive, I'm too stoned,' are starting to think it's wearing off,” said Tom Marcotte, co-director of the Center for Medical Cannabis Research The Wall Street Journal. “At least according to our analysis, there are still problems.”

Other studies show that the results of marijuana last even longer.

According to a study published within the journal, smoking can “impair essential driving skills” for six to eight hours, and eating edibles makes driving unsafe for 8 to 12 hours International Journal of Drug Policy.

“These times may vary from one usage context to another. “During these periods of impairment, driving or similar risky activities should be avoided,” the study says.