Just a couple of weeks ago, we addressed the issue of drugged driving, and the role that THC can play in driver impairment. We talked about the need for a roadside test to measure THC content reliably enough to stand up in Court, in support of a charge of operating a vehicle while impaired.

Appears we were ahead of the curve. Now comes significant new findings that  confirm some of our worst fears. From an article in Science Direct:

Nearly half of drivers killed in crashes had THC in their blood

The new study examined records of auto fatalities in Montgomery County, Ohio, population 536,000 (Dayton is the county seat). The researchers found that 42% of drivers who died in crashes during the six years of the study had high (in some cases, very high) levels of THC at the time of their fatal accident.

The article notes that most states where limits on THC content have been set put the level for driver impairment at or below 5 ng/mL. Yet the average result found in the Montgomery County study was a remarkable 30.7 ng/mL, or more than six times greater than the limit.

The study included 250-plus deaths, spanning the period from 2019 to 2024.

In view of those highly elevated THC levels, I have to think at least some of the drivers had been using potent concentrated forms, such as wax and shatter, as well as (or instead of ) ordinary pot.

Of interest is the fact that legalization, which happened during the period studied, appears to have had no real impact on the drivers. They’d been driving under the heavy influence of THC both before and after the change in the law — with presumably the same degree of impairment.

Samples, drawn postmortem,  did seem to indicate recent rather than past use. That’s of interest because drivers who test positive for THC are fond of arguing that the positive test was based on a joint they’d smoked a while ago – or even better, that somebody else in the car had been smoking.

The very high levels of THC found in the research seems to suggest otherwise.

The authors conclude by urging governments to issue stern warnings, akin to those currently used in DWI prevention campaigns. A quote: “People should treat smoking marijuana just like they treat alcohol: don’t smoke and drive.”

For that matter, best not to chew, swallow, suck, vape, or dab the stuff, either. Not if you’re planning to drive anywhere, at least.