Debate intensifies over THC limits for drivers

The University of Cincinnati's LaTrice Montgomery and Chris Tuell were featured in a Local 12 report discussing the nuances and difficulty in setting safe driving limits for THC, the active ingredient in cannabis.

In Ohio, Illinois, Montana, Nevada, and Washington, a blood test showing more than five nanograms per milliliter of THC can lead to an OVI charge, even if the driver shows no signs of impairment.

Montgomery said factors including each person's metabolism and whether the marijuana is smoked or ingested via edibles can all affect levels of impairment and how long THC is detectable in the body.

"Unfortunately, right now, we are unable to provide a specific level, and part of that is because there are many different factors associated with cannabis use," said cannabis researcher Montgomery, PhD, adjunct associate professor in the Department of Psychiatry and Behavioral Neuroscience in UC's College of Medicine.

Tuell, assistant professor of psychiatry and behavioral neuroscience in UC's College of Medicine and clinical director of addiction services at UC Health's Lindner Center of HOPE, said marijuana research is difficult because there are such widely varying levels of THC in different products.

"You know, back in the day, our dad's or mom's marijuana was like three to five percent, and every decade it's gone up. So, now when you go to a regular dispensary, it could be 15 to 20 percent THC," Tuell said.

Watch or read the Local 12 report.

Featured photo at top of marijuana leaves. Photo/Jeff W/Unsplash.