New Study Finds that Regular Cannabis Users Drive Just as Safely as Sober People

New Study Finds that Regular Cannabis Users Drive Just as Safely as Sober People

Published on 2/26/22

Watch any standup comedian whose shtick involves pot jokes, and you're sure to come across a riff on the laws against smoking weed and driving. "What's the danger," the punchline inevitably asks, "that you'll drive 10 miles under the speed limit and end up in the parking lot of a Taco Bell?" For a long while, it was assumed that combining driving and cannabis would result in disaster - you may remember the public service announcement commercials where a bunch of stoners behind the wheel drove forward in the direction of a kid on a bike - but like so many other things in life, it turns out that stoner wisdom was right all along. A new study out of the University of Colorado found that marijuana smokers who use cannabis daily have no significant changes in driving habits or safety compared to people who are sober. The study has major ramifications for cannabis law and policy, potentially leading to changes in how drivers are tested and punished for cannabis use.

Scientific Details

The UC study analyzed adults between the ages of 25 and 45 - in other words, prime smoking years in the stoner community. They separate occasional users (1-2 times per week), frequent users (daily), and non-users. Each of these groups were put in a driving simulator called a Minisim, which resembles the driving games you see at video arcades, except for the nitrous boosters. The Minisim tests tracked two important statistics: deviation from the street pathway, meaning how far you swerve in and out; and deviation from the speed limit, meaning how much faster or slower you go compared to the legal limits.

The occasional and frequent users smoked cannabis half an hour before being put behind the fake wheel of a Minisim, making them the luckiest guinea pigs in the history of science. The weed in the study had a 15% and 30% THC rating, meaning some got mids and some got some really, really good dank. The results speak for themselves: while those who toked up deviated from the street lane by about one centimeter more than the non-smokers, this is as big a swerve as the width of a finger and not statistically meaningful. Furthermore, regular smokers decreased their speed relative to the non-smokers by 1.15 miles per hour, meaning it would take them an extra hour to drive from New York to Los Angeles.

Weed and Wheels


The study indicates the over-exaggeration of the risk of stoners getting behind the wheel. It may be a while before it changes the law; however, it is against the law to drive while high, no matter what state you live in. Police who pull you over and run a test will charge you with a DUI, often regardless of the quantity of THC, they find in your system. Although states currently have no standardized approach to this, in the way that they do for drunk driving, they nevertheless follow some basics. Cannabis cannot be detected with a breathalyzer like alcohol, meaning that a blood test is necessary. However, these blood tests are notoriously inaccurate, unable to tell when cannabis was actually smoked, leading to the chance that a driver may be punished for toking up hours or even days ago. As the study suggests, higher quantities of THC in the bloodstream do not correlate with an increased risk of swerving or speeding.

Changing Minds

On its own, the University of Colorado study will probably not lead to drastic change. After all, much more cannabis research has shown that it delays reactions, alters your perception of time, and makes it harder to concentrate, all of which can potentially lead to harm on the road. Yet the research is part of a broader trend showing how cannabis myths are increasingly not holding up to scientific rigor. Just as cannabis legalization has demonstrated that usage and crime actually decrease, so too does research on cannabis use and interaction with the world show that stereotypes about everyone's favorite leaf just aren't true.

The focus is now on lawmakers to change cannabis law and policy. Some are eager to do so: just recently, the city of Philadelphia banned cannabis drug testing as a condition for employment screening. As the prohibition era (slowly) comes to a close, more opportunities for cannabis use in everyday life will follow. Whether that means an end to marijuana DUI laws remains to be seen, but it is clear that these are nowhere near as great a risk to society as alcohol DUI laws.

Do you have any experiences with smoking weed and driving? How have you dealt with the law when it comes to a cannabis DUI? Let us know in the comments below!

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