Marijuana Not a Factor in Driving Accidents

University of Toronto ^ | March 29, 1999 | Professor Alison Smiley

[davesdude]

Marijuana Not a Factor in Driving Accidents

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March 29, 1999

The safety hazards of smoking marijuana and driving are overrated, says U of T researcher Alison Smiley.

Recent research into impairment and traffic accident reports from several countries shows that marijuana taken alone in moderate amounts does not significantly increase a driver's risk of causing an accident -- unlike alcohol, says Smiley, an adjunct professor in the department of mechanical and industrial engineering . While smoking marijuana does impair driving ability, it does not share alcohol's effect on judgment. Drivers on marijuana remain aware of their impairment, prompting them to slow down and drive more cautiously to compensate, she says.

"Both substances impair performance," Smiley says. "However, the more cautious behaviour of subjects who received marijuana decreases the drug's impact on performance. Their behaviour is more appropriate to their impairment, whereas subjects who received alcohol tend to drive in a more risky manner."

Smiley, who has studied transportation safety for over 25 years, drew her results from a "metanalysis" of existing research into the effects of marijuana on driving ability, combined with traffic accident statistics in the United States and Australia. Previous studies showing stronger effects often combined "fairly hefty doses" by researchers with driving immediately after consumption, likely exaggerating the drug's effects, she believes.

While Smiley does not advocate legalizing the drug, she says her results should be considered by those debating mandatory drug tests for users of transportation equipment such as truck or train drivers, or the decriminalization of marijuana for medical use. "There's an assumption that because marijuana is illegal, it must increase the risk of an accident. We should try to just stick to the facts."

Smiley presented her findings at a symposium of the American Academy of Forensic Sciences in Florida in February. Her paper was also published in Health Effects of Cannabis, a publication of Toronto's Centre for Addiction and Mental Health, in March.

[Hemingway's Ghost]

So, let me get this straight: one can use the intoxicating substance alcohol socially without abusing it, but not the intoxicating substance marijuana?

[Trailerpark Badass]

I completely understand it's effects, but you make it sound as if a person who has never had a drop of alcohol will black out and wake up with a killer hangover after one sip.

I was trying to say the opposite: people with experience drinking develop behavioral tolerance to alcohol. Metabolically, they have the same intoxication level (BAC), but they are less impaired behaviorally. So, while the body is affected in exactly the same way by a drink or two, the experienced drinker notices it less and can handle the effects better. The same happens with marijuana.

But the notion that responsible drinkers are not experiencing ANY mood/perception effects after a drink or two is simply not true. Relaxation, a more convivial mood, an enhanced sense of well-being, these are all effects of alcohol that are noticed after the first drink. Those are the same effects I feel from smoking a "moderate" amount of marijuana. In fact, even after smoking "immoderate" amounts of the strongest marijuana in the world (in Amsterdam), the only real impairment I felt was a desire to take a nap.

The point of my post was for you to back up your assertion that "experience" makes one more able to deal with it's affects.

http://pubs.niaaa.nih.gov/publications/aa28.htm

[hodaka]

Your friend Mark most likely had head phones on listening to Pink Floyd. That's why he didn't hear you.

[davesdude]

well are you against sending to jail people who abused from a substance??? i would be okay with the fact that somebody driving under the influence of pot or somebody causing damage to the property under the influence of pot getting harsher penalty!

i don't understand your point?

and also if you tried marijuana you should be aware that you do not automatically start doing stuff you wouldn't normally, so don't go to jail for nothing!!

[American_Centurion]

Yes, unless they are medically prescribed marijuana to relieve symptoms.

See Post #120. Smokin' Joe has articulated my point extremely well in the last few sentances of his post.

[American_Centurion]

You go to jail for participating in the trafficking of a controlled substance. Not for doing nothing.

[Echo Talon]

Your friend Mark most likely had head phones on listening to Pink Floyd. That's why he didn't hear you

NO, he would just sit there and zone out, i hated getting stoned with him, it was like i was by myself because he would just space out.

[jmc813]

When the vast majority (overwhelmingly vast) drink alcohol solely for the social aspect of it

Are you one of those weirdos who drinks non-alcoholic beer?

[enraged]

There is a test, involves involuntary eye movement, plus many Highway (no pun intended) patrol officers are DRO certified, Drug Recognition Officers. bottom line if you are stoned, beyond maybe a little high it is detectable by someone trained to look for it.

[hodaka]

Kind of a broad statement that you believe that the majority of folks with prescription marijuana are doing it for the buzz. How about the folks that take the hillbilly heroin oxycontin? Will you also say they are doing it for the buzz. Do you think that Montell Williams is lying when he said that his pot use is beneficial when he is battling multiplescorosis or do you think he is only doing it for the buzz?

[Lady Jag]

Actually, it was a 60 Minutes TV promo that got me reading up on it. A little over a month ago, I think, 60 Minutes had a segment on Marc Emery (spelling?).

I never watch 60 Minutes, but when I heard the promo, I was brought back to 1970, when I was reading and researching the subject to suddenly have all resources ripped from my hands by making all such things illegal and evil. I couldn't even buy or borrow a book on it.

Oddly, back then I switched to researching American's attitudes toward law.

So, is it correct that it is legal to grow hemp in Canada, but smoking pot is still not legal?

[ozzymandus]

Back in the day, when I drove stoned, I was so paranoid I drove very slowly and carefully to avoid any trouble with the cops. All the accidents involving me and my friends were alcohol-related.

Remember the old joke about the tripping hippie whose van is stopped by the cops? Cop says, "Do you know how fast you were going?"
Hippie thinks for a long time, remembers how to talk and says "70?"
Cop says, "5. Get out of the van."

[DAC21]

Steering the car with your knees while holding a lighter in one hand and a bong in the other never caused an accident, or coughing up a lung for that matter. /s

[TypeZoNegative]

That's because most people who smoke can't afford to buy a car, dude!

[Echo Talon]

or driving around with the car so cheeched that you cant see out the windshield is also a recipe for disaster. :)

[American_Centurion]

That article refers to "Chronic Heavy Drinkers" (abusers??) and does not in any way relate to the social drinking I posted about.

[hodaka]

Your friend Mark didn't sound like such a fun guy to be around. In my younger days when we would catch a buzz, we would laugh at the dumbest jokes and listen to alot of Led Zeppelin, and Pink Floyd, but no one ever got violent. When I hung around some folks who drank at a party or something, you could always count on a drunken fight breaking out over the dumbest thing, or some drunk kid throwing up in the house or in someones car.

[Hemingway's Ghost]

So easily defeated . . .

Not so with marijuana, where there is variety in potency, dose consumed, effects on any given individual, etc. The results cannot be reliably 'normalized', nor can the dosage be anticipated during consumption as in the case of alcohol.

Bravo Sierra. Just as you can judge how much alcohol you can drink before you become too intoxicated to drive, I can judge how much marijuana I can smoke before I become too intoxicated to drive. It's not rocket science.

[ozzymandus]

That was exactly what happened to me. After a few years of smoking dope, I started to get really scared and paranoid every time I got high. It got to where after even a couple of tokes all I could do was go home and hope the phone didn't ring until I came down. I realized pretty quickly that I wasn't having fun, and haven't smoked for about 20 years.

[American_Centurion]

No I drink Scotch. Expensive scotch.