Like many people, you may be concerned about potentially sharing the road with someone who’s driving while high. Unfortunately, much of this apprehension is fueled by misunderstandings, stereotypes, and erroneous past studies. So, here’s the truth about cannabis and driving.
The confusion surrounding driving and cannabis
One of the most widely shared concerns many people hold in response to spreading cannabis legalization is the potential combination of driving and CBD (cannabidiol, one of the most prominent cannabinoids in hemp flower). Never mind that science has repeatedly demonstrated the lack of CBD’s intoxicating effects on the human mind.
For some, the close relation between CBD and THC is enough to worry people about what could possibly happen behind the wheel due to excessive doses. Unfortunately, it seems that past erroneous research has contributed to the growing fear. Even the scientists themselves raised the alarm in past publications, referring to cannabis-impaired driving as one of three “primary reasons for concern about legalized cannabis.”
Initially, estimates showed that using cannabis while driving can increase your crash risk by two to three times. This approximation was based on lab and epidemiological (disease-related) research. Researchers also considered experimental studies to support these findings since many found “driving-relevant abilities” – not the act of driving itself – to be impaired three to four hours after cannabis consumption.
By 2016, some researchers began to question the methodology behind these stats. They brought up the fact that the quality of many cannabis evaluations is a “known issue” since one of the most common practices is measuring cannabinoid concentrations in urine, producing inaccurate results.
Additionally, small sample sizes tend to inflate results, leading to the belief that risks are higher than they are in reality. Reliance on non-random sampling also interferes with data accuracy. In other words, some scientists can’t get control groups because drivers refuse to be tested for cannabis in traffic stops.
These only represent a handful of the most pressing issues facing cannabis-positive driving studies. Ultimately, researchers found that the collection of problems led to a “substantial” overestimation of the relationship between cannabis use and a driver’s crash risk.
Instead, the review showed that more widespread legalization of cannabis nationwide would only have a “low to moderate” effect on crash rates. Interestingly, the researchers pointed to past case studies on staggered legalization of medical marijuana throughout the US.
As political pressure on the herb eased up state-to-state, records showed a net reduction in traffic risks in the same regions. This may be due to two possibilities:
- Drivers were transitioning from alcohol (the higher crash-risk substance) to cannabis (lower risk).
- Cannabis users were more likely to stay home and smoke or consume edibles rather than go out driving.
Still, scientists are wary of saying this part out loud. The research team who questioned past overestimations stated in their publication: “[If] the low estimates are taken as evidence that ‘driving after cannabis use’ is unproblematic, the new users would tend to be more impaired and have a higher cannabis-induced increase in crash risk.”
For this reason, it’s up to the members of the cannabis community to exercise discretion. This research certainly does not encourage the intentional excessive use of cannabis before operating a vehicle. Rather, it serves as a fundamental source of knowledge with which the public can break down stigmas and misunderstandings attached to the cannabis plant.
Why “cannabis-positive” driving isn’t quite the problem
Part of the reason why cannabis-positive driving hazards are less of a threat than alcohol-influenced driving is that someone who has consumed cannabis is more likely to be aware of their state of mind. For example, people can retain more control over their thoughts and actions after smoking or eating hemp-derived products than after drinking a few beers.
Although the foundation of research into cannabis’ effects on the brain compared to alcohol is lacking, a landmark study in 2018 illustrated this sustained awareness very clearly. Scientists scanned the brains of 853 adults between 18-55 years old and 439 teens between 14-18.
The results showed that those who reported alcohol use had reduced grey matter and “compromised” white matter.
(Grey matter is the outer part of the brain containing lots of nerve cells and fibers. It helps you process information, control emotions and movement, and form memories. White matter contains nerve cells and fibers, too, deeper in the brain. It’s where these components send nervous system signals back and forth across the brain.)
On the other hand, marijuana users did not display any gray or white matter changes whatsoever. This means they were less susceptible to impaired mental functioning and memory loss. It’s important to note that this study illustrated the risk difference on a more long-term scale. Still, this goes to show that you face fewer cognitive risks with cannabis versus alcohol use, according to current knowledge.
Additionally, driving while cannabis-positive is not necessarily the sole indicator of a high crash risk. In the academic review discussed above, the researchers pointed out that the decision to drive after consuming a potentially mind-altering substance is a personality trait of people who are already predisposed to risky driving.
This sort of decision-making is common among people who engage in the following behaviors on the road:
- Driving at high speeds
- Following other cars closely
- Dangerously shifting lanes
- Drinking and driving
Since this personality type exists independently of cannabis use, these behavioral profiles may inflate bias in cannabis-positive driving studies.
Latest studies declare CBD “does not impair driving”
Research into cannabis use and driving continues, with the latest historical findings emerging in December of last year. Scientists officially laid to rest part of the world’s debate on whether cannabis use can negatively impact a driver’s ability to operate a vehicle safely.
More specifically, they demonstrated that CBD-rich hemp would not impair driving abilities and published their findings in the Journal of the American Medical Association.
This is a critical distinction, as CBD and THC do not cause the same cognitive effects as one another. Of course, the effects cannabinoids impose change from person to person. Still, delta-9-THC has a uniquely psychoactive effect on the mind, causing a warped perception of time and possible motor changes, among some of its more desirable effects like providing a sense of calmness and relaxation.
Because of this difference, operating a vehicle after consuming CBD does not equate to “driving while high” like with THC consumption. The new research is a game-changer, finally yielding solid evidence to refute needless worry that can potentially shift legislation against further legalization.
Dr. Thomas Arkell, the new study’s lead author, told the University of Sydney, “These findings indicate for the first time that CBD when given without THC, does not affect a subject’s ability to driving. That’s great news for those using or considering treatment using CBD-based products.”
The researchers came to this conclusion after testing 26 healthy drivers who vaped cannabis with either CBD or THC. The vaporizer was distributed on four separate occasions and given in random order. The participant was then tested in controlled highway conditions in a dual control car for safety purposes.
Ultimately, the CBD and a CBD-THC combination were found not to impair drivers, while THC showed “mild” impairment after 40 minutes, but no later than four hours after consumption.
For years, people have worried about the potential consequences of expanding cannabis legalization. One of the most prominent fears has been increased driving accident rates. Yet, new research in recent years has shown time and again that driving after the use of CBD-rich cannabis, or hemp, is nothing to worry about.
Still, since cannabis is known to have varying effects between individuals, it’s best to practice discretion, especially if you’ve consumed THC. This cannabinoid has starkly different psychoactive effects and may indeed increase your crash risk.