Does CBD affect driving? Researchers aim to find out

A US university is recruiting participants to study the effects that CBD oil has on driving. 

Sales of CBD have hit the gas of late, but despite its widespread use, scientists don’t yet fully understand all of the ways it affects drivers. 

Researchers with the West Virginia University School of Public Health are currently recruiting participants for a new study into whether and how CBD oil impairs driving ability. 

The study will involve 40 participants, half of which will be given 300 mg of pure CBD oil, the other half will receive a placebo.

The study is “double blind,” meaning neither the participants nor the researchers will know who has received the real or placebo doses.

“We don’t really know much about CBD,” said Toni Marie Rudisill, a research assistant professor in the Department of Epidemiology and Biostatistics.

Toni Marie Rudisill, a research assistant professor in the Department of Epidemiology and Biostatistics.

“There’s not a whole lot of research on it. But there were all these anecdotal reports of people using it to help them sleep or help them relax. And as an injury epidemiologist, my first thought was, ‘OK, then: if it’s making you tired, how does that impact your performance or make you more prone to injuries?’”

After taking their assigned dose, participants will complete a driving simulation that takes about half an hour.

The simulator can show how often a participant drifts out of their lane, whether they use turn signals appropriately and whether they stop at traffic lights.

If a participant is waiting to turn left at an intersection, it can reveal whether they properly judge the speed and distance of oncoming cars. If a pedestrian darts into the road, it can identify whether the participant brakes in time.

“The driving simulator doesn’t look impressive—it looks like a regular old computer game—but it’s amazing what it captures on the back end,” Rudisill said.

“What makes the simulator really great is that it provides a safe environment for people to drive in and where we can still assess performance.”

She and her colleagues will measure the participants’ driving performance and compare it between the two groups.

In addition, the researchers will assess the participants’ mood, drowsiness, sedation, reaction time and cognitive function, before taking the CBD oil or placebo and after finishing the driving simulation. 

“We’re looking to see if their mood changes. Do they feel more tired? Will we see any cognitive changes that are maybe due to drowsiness?” Rudisill said. 

“We’re interested to see how those variables relate to the driving measures.”

Last year a study led by the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney showed that CBD appears to be safe for drivers.

The research involved people inhaling vaporised cannabis containing different mixes of THC and CBD, before going for a 100-kilometre drive under controlled conditions on public highways both 40 minutes and four hours later. 

Cannabis containing mainly CBD did not impair driving while cannabis containing THC, or a THC/CBD mixture, caused mild impairment measured at 40 minutes later but not after four hours.