It seems kind of obvious to me that people driving on dope are “impaired.” I mean, come on. Didn't you ever see a Cheech and Chong movie?


Now a new Canadian study, published in the British Medical Journal, says that drivers who get one toke over the line—smoking cannabis three hours before hitting the highway—“are nearly twice as likely to cause a vehicle collision as those who are not under the influence of drugs or alcohol.”


According to the study, marijuana is the “most widely used illicit substance globally,” with toking up around the world. A 2007 study in Scotland based on interviews with 537 drivers, 15 percent of those between 17 and 39 admitted blowing gage within 12 hours of driving. Another study I saw said that 11 percent of North Americans smoke pot. (And 10 percent of Britons; see the video below).


I thought to check in with the chief American apologist for smoking dope, the National Organization for the Reform of Marijuana Laws (NORML). The group has most recently been caught up in the fight for medical marijuana, but I wasn’t surprised that it also deals with driving on cannabis, with rather different conclusions than the Canadian study. According to NORML’s website:


Evidence of marijuana’s culpability in on-road driving accidents is much less convincing [compared to alcohol]. Although cannabis intoxication has been shown to mildly impair psychomotor skills, this impairment does not appear to be severe or long lasting. In driving simulator tests, this impairment is typically manifested by subjects decreasing their driving speed and requiring greater time to respond to emergency situations. Nevertheless, this impairment does not appear to play a significant role in on-road traffic accidents.

And is it surprising that the “straight dope” from the marijuana growers also exonerates recreational use of the substance? “Regular cannabis users who engage in activities like video games or recreational sports after smoking a joint argue they perform better on pot. Which is true to some degree. Marijuana in moderation does appear to have little effect or influence on motor vehicle performance.”


Marijuana is a drug, the effects of which can include (but are not limited to) “fatigue, paranoia, possible psychosis, memory problems, depersonalization, mood alterations, urinary retention, constipation, decreased motor coordination, lethargy, slurred speech, and dizziness.” I didn’t make those effects up, but got them from the website of the National Highway Traffic Safety Administration (NHTSA), which is much better known for being against drunk driving than it is for its thoughts on pot.


But the federal agency is clear that driving and doping don’t mix, in fact it points out specifically that dopers don’t do well in driving simulator tests:


Epidemiology data from road traffic arrests and fatalities indicate that after alcohol, marijuana is the most frequently detected psychoactive substance among driving populations…Decreased car handling performance, increased reaction times, impaired time and distance estimation, inability to maintain headway, lateral travel, subjective sleepiness, motor in-coordination, and impaired sustained vigilance have all been reported. Some drivers may actually be able to improve performance for brief periods by overcompensating for self-perceived impairment. The greater the demands placed on the driver, however, the more critical the likely impairment. Marijuana may particularly impair monotonous and prolonged driving.


I contacted NORML’s spokesman Paul Armentano, and he gave me a rather more nuanced view on the issue than was apparent on the group’s website. Armentano said the Canadian study’s findings “reaffirm many accepted understandings regarding acute cannabis intoxication and psychomotor performance.” He admitted that such acute intoxication “appears to elevate some people’s accident risk in a dose-dependent manner.” He concedes that operating a car while high on cannabis is a criminal offense in all 50 states.

That said, he went on to point out that the marijuana connoisseur, a/k/a “the more experienced cannabis consumer” will experience changes in performance that are typically “subtle, short-lived, and less dramatic.” And, of course, the elevated risk is far less than from alcohol, “including its use in legal quantities.” Readers of High Times, in other words, can handle their dope.


Personally, I think the bottom line is pretty clear: Don’t get stoned out of your mind and try to drive a car. Here's more evidence, by way of a British video:


Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

The straight dope on driving stoned
A new Canadian study says that piloting a car after smoking marijuana nearly doubles your chances of getting into a serious accident. But don't tell that to NOR