New Study Shows CBD Unlikely to Impair Driving, but Legal Risks Persist

Sure enough, a new study from researchers at The University of Sydney found that, unlike THC, which can cause motor skill impairment that last up to a few hours, CBD does not appear to impact driving. But, whether or not it’s worth the legal risk to drive with a CBD product in your system is another story.
Written by 
Alexa Peters, Cannabis Writer.
|Last Updated:
CBD and driiving

Decades of peer reviewed literature show that alcohol impairs driving. In fact, according to the National Highway Traffic Safety Administration, almost 30 people in the United States die in drunk driving related crashes every day. As a result, there are many concrete federal and state laws that prohibit driving under the influence of alcohol.

What’s more, if you’re found to have more than the legal limit of tetrahydrocannabinol (THC), the intoxicating cannabinoid in cannabis, in your bloodstream after a traffic accident you could also be charged with DUI. But what about driving with cannabidiol (CBD) in your bloodstream? This legal, non-intoxicating constituent of cannabis is trendier than ever due to its potential to ease pain and anxiety and other issues.

What the New Study Found

For the landmark study, researchers from the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney worked with 26 healthy adults in a cross over clinical trial. Participants were split into groups and asked to vaporize one of three cannabis types: CBD dominant cannabis, THC dominant cannabis, and THC/CBD equivalent (1:1) cannabis. All doses were 13.75 mg. About an hour later, each participant underwent a standardized road driving test during a 100 kilometer drive under controlled conditions.

Based on the standard deviation of lateral position (SDLP), which measures the degree to which a driver weaves in and out of lanes, overcorrects and/or swerves, they found that the driving of those participants who’d used the 1:1 strain, and in particular those who’d used the THC dominant strain, had the highest SDLP during their driving test. Meanwhile, those drivers who’d vaporized a CBD dominant strain scored the lowest.

“These findings indicate for the first time that CBD, when given without THC, does not affect a subject’s ability to drive. That’s great news for those using or considering treatment using CBD based products,” lead author Dr. Thomas Arkell said in an interview with the University of Sydney.

All that being said, the study is also quick to acknowledge that dosages and results may vary from person to person and that more research must be done to be certain about this issue. Still, researchers say the results are promising when it comes to easing worries experienced by people using CBD therapeutically, like the 64% that reported they used CBD for pain and inflammation in a 2020 survey.

“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,” said Arkell.

What the Law Says

But even as this new research points to THC as the major culprit in cannabis related car accidents and DUIs, and clears CBD as “likely safe” for driving, you could still run into legal issues if you get behind the wheel after consuming CBD.

After all, every state has different laws governing cannabis, and the legal risk of taking CBD and driving depends heavily on the regulations in the state you live in and the type of CBD product you use.

For instance, Illinois, Montana, Nevada, Ohio, Pennsylvania, and Washington enforce a “per se” legal limit for THC ranging between 1 nanogram and 5 nanograms, reports the NCSL. In a similar manner to a legal blood alcohol concentration, if a driver is shown to surpass the “per se” limit in the state where they are pulled over, this constitutes grounds to prove impairment.

Meanwhile, states like Arizona, Delaware, Georgia, and Wisconsin, take an even stricter position by imposing a zero tolerance standard for certain drugs, including THC. This means that if any THC is found in your bloodstream after an driving incident, you could be charged with driving under the influence. (This is a particularly scary law, too, when you consider that THC can linger in the body for as many as 30 days after initial consumption.)

These laws, though focused on THC, may cause you to be charged with a DUI offense even if you take your favorite CBD tincture from behind the wheel. This is because some of the most popular and potentially effective CBD products are full spectrum products that include the trace amounts of THC. This small amount of the THC, in combination with CBD, creates a synergy called the entourage effect which may optimize the healing potential of a CBD product. At the same time, these trace levels of THC may cause you to fail a cannabis breathalyzer or blood test.

What’s more, while there are two other types of CBD that may be seemingly safe to drive with; isolate, which is 100% pure CBD, and broad spectrum, which has been processed to remove THC content, labeling integrity and oversight is a major issue in the industry you could end up paying for these issues .

“For drivers, this means if you thought you were taking CBD without THC, and an accident happens and THC is found in your system, you could be arrested for DUI,” states one article on the website of Steinlaw Injury Lawyers.

So, while new research has revealed that CBD is less likely to impair driving than THC or alcohol, there is still legal risk associated with driving under the influence of your favorite CBD product. State laws against driving under the influence of cannabis are largely unforgiving and full spectrum or misleadingly labeled CBD products may cause you to fail a cannabis blood or breathalyzer test. Hence, using CBD while driving poses many legal risks that may not be worth taking, even if CBD is integral to easing your pain, anxiety and other diagnosed health issues.

Alexa Peters
Alexa Peters
Cannabis Writer
Alexa Peters is a Seattle-based freelance writer and editor with a specialty in arts & culture, wellness, and lifestyle journalism, as well as content writing. My cannabis and CBD-focused work has appeared in Leafly, CannabisMD, Healthline, Green Valley Nation, and many other publications.

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