The Great Marijuana Myth: Is Driving High Dangerous?

A recent study finds that drivers who smoke marijuana within a few hours of driving are more likely to get into an accident than sober drivers. Find out how much more.

Marijuana plant

Last week, the British Medical Journal published a study about the effects of smoking cannabis (aka marijuana, pot, weed, Mary Jane) on driving ability. Researchers at Dalhousie University in Nova Scotia, Canada, analyzed 9 prior studies and concluded that — contrary to most pot smokers’ beliefs — driving high leads to a higher risk of car accidents.

Now, before we go any further, let’s address the elephant in the room: pot is illegal in most states. But (as we know) people smoke it regardless of what the law says. However, no matter what folks tell you, driving under the influence of any controlled substance is illegal and dangerous.

We could write endlessly about reckless driving — drinking, using a cellphone, and even driving tired all put you and others at risk — but for our purposes today, let’s focus on Dalhousie’s study and the specific dangers of smoking pot and driving.

Weed and driving effects

Turns out, drivers who smoke marijuana within a few hours of driving are almost twice as likely to get into an accident as sober drivers. And though the accident stats aren’t as bad as they are for drinking and driving, the risk is palpable.

While alcohol is still the most common accident-inducing substance, a recent survey quoted on the National Institute of Drug Abuse’s Web site found that 6.8 percent of drivers who were involved in accidents — most of whom were under 35 — tested positive for THC (the chemical found in marijuana).

Smoking weed and driving laws

Unlike testing for alcohol levels, researchers and law enforcement officials have not yet determined how to accurately test for levels of marijuana intoxication. Many states, however, have begun to take a hard line on this public safety issue and police officers are now being trained to detect signs of marijuana intoxication. And make no mistake about it: driving a motor vehicle while under the influence of drugs — including legal-use marijuana — is illegal in all states.

Get a breakdown of drugged driving laws here.

The great marijuana myth

It’s possible you’ve heard a pot aficionado state:  “I’m a better driver when I’m stoned.” Not true. A major issue with drugged driving is that when you’re high (well, not you specifically, we know you’d never do that), you don’t always realize that your judgment is impaired. This is especially true for teenagers who are already at-risk drivers. Couple this with a few hits of ganja, and the buzz can become, well, killer.

Though it varies by person, it generally takes at least 3–4 hours to come down from a high. No amount of strong coffee or greasy food is going to sober you up faster.

Drinking and driving vs. smoking weed and driving

Most of us grew up hearing “don’t drink and drive,” but not nearly as much effort was put into preventing the combination of smoking pot and driving. Yet marijuana affects reaction time, spatial sense, and perception — all of which are crucial to safe driving. So when a person is driving high, they may end up following another car too closely (and brake too late), make unsafe turns, or misjudge road hazards.

The fact remains: weed and driving don’t mix

In the coming years, we may see a move toward the legalization of pot. But no matter where you stand on the issue — “a need for weed” or “not for pot” — we should all be on the same page when it comes to designating a driver who abstains from ALL mind-altering substances (legal or not).

If you’re into graphs and footnotes, you can read the whole British Medical Journal study here.

Related links

Driving on drugs: stats and facts
National Institute of Drug Abuse article on drugged driving
National Institute of Drug Abuse research report on marijuana abuse
CNN reports marijuana nearly doubles the risk of collisions
Dalhousie University report

321 Responses to “The Great Marijuana Myth: Is Driving High Dangerous?”

  1. David
    October 21, 2013 #

    " 6.8 percent of drivers who were involved in accidents — most of whom were under 35 — tested positive for THC (the chemical found in marijuana)."

    Yeah and what were their BACs??? You can have a drink or two or take a couple tokes and drive fine but if you put them together? Watch out. I myself can have a couple of beers and be fine but take a couple tokes afterwards? I can find myself staggering!

    Stick to cannabis…It's much better for you… In multiple ways… Physically, mentally and spiritually…

  2. Dewewantto
    October 22, 2013 #

    Why can I play my Race Car 3 game Better and Safer when I'm stone?

  3. smartypants
    October 24, 2013 #

    Driving under the influence of drugs and/or alcohol is a childish mistake. grow up, don't drive after recreational intoxication . period! That is all