A rising number of marijuana users are getting behind the wheel while high — and it’s turning deadly.
A new study found that more than 40% of fatal crash victims over the past six years had elevated THC levels in their blood. The drug screenings were done during autopsies.
THC, the compound responsible for marijuana’s high, was found in nearly 42% of the 246 Ohio drivers studied by Wright State University researchers.
On average, their blood levels hit 30.7 ng/mL — six times higher than the legal limit in many states.
Those levels stayed consistently high even after Ohio legalized recreational cannabis.
Lead author Dr. Akpofure P. Ekeh said he was shocked by the findings. “An average level of 30.7 ng/mL generally means those people must have consumed marijuana at some time close to driving,” he said. “This isn’t about residual use; it’s about recent consumption.”
The study will be presented this week at the American College of Surgeons Clinical Congress in Chicago.
Ekeh said the public conversation around legalization has ignored serious risks. “People should treat smoking marijuana just like they treat alcohol: Don’t smoke and drive,” he warned.
Dr. Laura Markley, an addiction specialist at Akron Children’s, echoed his concern. “THC slows reaction time, clouds judgment and dulls coordination — and those few seconds of delay can be the difference between a near-miss and a fatal crash,” she said.
She warned that even small amounts can impair drivers. “Emerging research shows that any amount of THC can impair driving,” she said. “The growing strength of modern cannabis products may make that impairment worse or last longer.”
Markley added that even those with high tolerance aren’t immune. Reflexes slow, focus narrows, and judgment falters — a dangerous mix behind the wheel.