As interest in cannabidiol (CBD) products grows, researchers continue searching for answers to some of the most popular questions among consumers. One recent discovery shows that CBD does not affect someone’s ability to drive a motor vehicle. However, the same cannot be said for tetrahydrocannabinol (THC).
A recent, placebo-controlled, double blind study tested the driving performance of its test subjects after they inhaled vaporized cannabis. Each participant was tested in four separate sessions that occurred a week apart.
The cannabis they inhaled contained different mixes of THC and CBD, and the order of the cannabis doses were administered at random. The four cannabis blends included one that mostly contained THC, one that mostly contained CBD, one that contained both cannabinoids, and a placebo that contained less than 0.2 percent cannabinoids.
After researchers administered a dose of cannabis, each test subject got into a dual controlled car with a driving instructor and drove 100-kilometers on public highways in the Netherlands.
Each participant’s driving performance was tested 40 minutes after consumption and four hours after consumption. These assessments were conducted with a well-established scientific test that measures vehicle position, lane weaving, swerving, and overcorrecting.
The results of the study showed that the a 13.75 mg dose of CBD had no impact on the driving performance of the participants. The study reportedly notes that the results of the driving tests taken after consuming CBD were consistent with the results of the tests taken after consuming the placebo.
“These findings indicate for the first time that CBD, when given without THC, does not affect a subject’s ability to drive,” Dr. Thomas Arkell said in a news release from the University of Sydney. Arkell is the lead author of the study.
It also showed that a 13.73 mg dose of THC caused driving impairments 40 minutes later, but not four hours later. A does of cannabis that contained both CBD and THC caused the same level of driving impairment as seen with THC alone.
The authors of the study reportedly said that the degree of impairment seen in this part of the study is comparable to the degree of impairment a driver might experience with a blood alcohol concentration of 0.05%. This is just shy of the 0.08% federal limit.
The results of this study were published December 2020 in the Journal of the American Medical Association. This University of Sydney-led experiment is only the most recent study to examine the effects of cannabis on driving abilities. However, Iain McGregor, academic director of the university’s Lambert Initiative for Cannabinoid Therapeutics, explained in a news release how this study was different from previous studies.
“With rapidly changing attitudes towards medical and non-medical use of cannabis, driving under the influence of cannabis is emerging as an important and somewhat controversial public health issue,” McGregor said.
“While some previous studies have looked at the effects of cannabis on driving, most have focused on smoked cannabis containing only THC (not CBD) and have not precisely quantified the duration of impairment,” he added.
McGregor explained that this is the first study to show that CBD does not affect someone’s ability to drive safely and to document the duration of impairment caused by THC.
He added, “The results should reassure people using CBD-only products that they are most likely safe to drive, while helping patients using THC-dominant products to understand the duration of impairment.”