February 4, 2023

High Doses of CBD Oil Won’t Impair Driving Ability, Australian Study Finds


Photo by Sebastian Kahnert / picture alliance via Getty Images

Australian researchers have found that even the highest doses of cannabidoil, otherwise known as “CBD”, have “no impact” on a person’s cognitive ability while driving. 

The findings arrive as part of a study conducted by researchers at the University of Sydney, which found that those who had taken 1,500 milligrams of CBD—the highest daily medicinal dose of the ​​cannabis component commonly prescribed—were otherwise able to drive as usual, drawing a consensus with similar studies undertaken around the world. 

“Though CBD is generally considered ‘non-intoxicating’, its effects on safety-sensitive tasks are still being established,” said lead author Dr Danielle McCartney, from the University’s Lambert Initiative for Cannabinoid Therapeutics. “Our study is the first to confirm that, when consumed on its own, CBD is driver-safe.”

“Unlike THC, a cannabis component that can induce sedation, euphoria (a high) and impairment, CBD does not appear to intoxicate people. Instead, it has been reported to have calming and pain relief effects.”

As part of the study, researchers had 17 participants undergo simulated driving tasks after taking either a placebo or 15, 300 or 1,500 milligrams of CBD oil, the three most commonly consumed dosages prescribed by doctors.

According to the study, participants were first asked to “maintain a safe” distance between themselves and the vehicle ahead of them, and then drive along simulated highways and rural roads, between 45 and 75 minutes after taking whichever treatment they were assigned.

The participants were then asked to do the drive again, about four hours later, to ensure that the range of plasma concentrations present at different times were fully covered. Each participant repeated this process under the influence of each of the four treatments, including the placebo and varying CBD dosages.

Whether or not the participants had in fact suffered some sort of cognitive impairment was then determined by how much drivers weaved or “drifted”—a reportedly “standardised” measure of driving ability—along with their overall cognitive function and the CBD concentrations in their plasma.

The results found that none of the dosages tested induced feelings of intoxication among the participants and didn’t appear to impair their driving ability or their cognitive performance. 

“We do, however, caution that this study looked at CBD in isolation only, and that drivers taking CBD with other medications should do so with care,” Dr McCartney said.

Australia is one of many jurisdictions around the world where it is perfectly legal to drive while using CBD, as long as the drug is prescribed legally. In the state of New South Wales, for instance, it is legal so long as a driver doesn’t suffer “impairment” as a result of fatigue or low blood pressure after using the substance.

This most recent University of Sydney study joins a throng of others like it from around the world. 

In 2020, researchers at the Netherlands’ Maastricht University came to similar conclusions. They conducted a similar study with 26 healthy participants who underwent driving tests after inhaling four types of vaporised cannabis containing various mixes of CBD and tetrahydrocannabinol (THC).

That study was one of the first of its kind to probe the impacts of CBD-use on driving ability, and offered promise to academics and policymakers around the world, as medicinal cannabis products began to build mainstream popularity. 

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Read more from VICE Australia.