An alarming trend is emerging on America’s roads.

More drivers killed in crashes are testing positive for THC, the active ingredient in marijuana.

Researchers in Ohio reviewed autopsy records from 246 drivers killed in crashes between 2019 and 2024.

They found that 41.9% had THC in their system — at levels far above what most states consider impairment.

The average blood level was 30.7 nanograms per milliliter. By comparison, many states set legal limits between just 2 and 5.

The researchers say that means the drivers likely used marijuana close to the time of the crash. The study also found the high rate of THC positivity stayed consistent over six years and didn’t change when recreational pot became legal in Ohio in 2023.

The lead author says from a public health standpoint, there hasn’t been enough attention on the dangers of legalization.

He says, “People should treat smoking marijuana just like they treat alcohol: don’t smoke and drive.”

The authors say these findings highlight the urgent need for increased awareness about the dangers of drugged driving

and the establishment of a safe legal THC limit.

These study results were presented at the American College of Surgeons (ACS) Clinical Congress 2025

Author Affiliations: Wright State University

Fatal Crashes Reveal High THC Levels in Many Drivers

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