How stoned is too stoned to drive?


However high the guy who ran a red and t-boned me was… (pretty f-ing high – told the insurance company that I thought that I had drove into a Cheech and Chong set)


At least one more.

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I know virtually nothing about cannabis, and I have no wish to try it, but I would imagine that the primary difficulty in attempting to measure how stoned you can be to carry out a given task is that its virtually impossible to gauge how much of an intoxicant is in the product before consumption. Whereas with drink, the recipe dictates alcohol content and as such all drinks are labelled with accurate measurements, as most cannabis products are home made, and consist of vastly varying grades of active ingredients, any measure is at best a guess.

My, pretty limited, personal experiences make me think driving stoned is probably pretty horribly dangerous.

The good news is that it also seemed that stoned people were markedly less likely to go anywhere.


Paging Dr @teapot


In place where it is legal, it is actually already fairly easy to get consistent and detailed information on the amount of substance in the product, and that will only improve as regulation and tracking catches up.


And now the opinion of Mr. Bill Hicks:

Why the hell does everyone always bring up Cheech & Chong? The real hippie comedians were Firesign Theater:


We’re all Bozo’s on this bus.


At least one major review has already been published. It’s available in BMJ, and is titled “Acute cannabis consumption and motor vehicle collision risk: systematic review of observational studies and meta-analysis” (BMJ 2012;344:e536) It’s a Canadian review of multiple studies from various countries, resulting in a review of over 50,000 motor vehicle collisions that included cannabis as a contributing factor.

What they basically found was this:

At slow speeds, stoned driving isn’t too dangerous. People are cautious while high, because they realize that they are, so fender benders aren’t much of an issue. What is a problem is driving at any high speed and fatal collisions. Cannabis use increased the rate of high speed collisions and death from those collisions. The possible reason given is that even though people know they’re high, they still don’t account for how much it impairs their reaction time and other driving skills.

In addition, although not many studies offered information, increased levels of thc were shown to have direct impact on driving. “Only three of the reviewed studies included calculations of odds ratios at differing tetrahydrocannabinol concentrations; in all three studies, raised amounts of the substance increased the risk of crash.” People who buy medical marijuana, may buy what is advertised as “low dose” expecting a lower active thc content, but other studies have shown that medical marijuana dispensaries are not standard in their evaluations of drug content within types of marijuana. It’s like someone drinking a beer, but it has a shot in it - they don’t expect the extra kick, and while they expect to have some reaction from the drug, they may take risks that are inappropriate for the level of drug consumed. That’s one more risk people should know about if driving stoned.


As a resident of Washington state, where it’s now legal, this is pretty important to me. I used to drive high all the time and I would say that if anything, it was never an issue. I would drive at much more reasonable speeds and be completely zoned into what I was doing. That’s my two-cents on the “while high” issue. However, a friend of my family got into an accident years ago where he was literally smoking while driving. He took too big of a hit, began coughing and ran into a freeway divider. No one else was involved but the injuries to himself we’re catastrophic. He’s still functional but required massive amounts o plastic surgery.

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Ever write down some of the brilliant/hilarious things you and your friends have said while stoned, and then read them later on when you’re sober? An ex of mine used to send me postcards from his summer job in Alaska, filled with the ramblings of him and his stoned friends. They were… unique.

What I’m saying is, self-perception has some pretty serious limitations when it comes to judging “how functional was I?”


Thought. What about some sort of smartphone app, game-like, that gauges attention and reaction speed? Score below x -> driving is a bad idea?

Would work not just for being stoned but also for being tired.


When I lived in Iowa City (where the study is taking place) a traffic jam was four cars at a 4-way stop each trying to yield the right-of-way to the other. I cab’t imagine what will happen when cannabis is added to the mix.


For what it’s worth, I theorized years ago that pot would never be federally legalized until they figured out a way to plug it into the DUI revenue machine. In that way, perhaps this study bodes well for the future.

It’s a fair point, true but every speeding ticket or accident I’ve had came after I quit smoking.

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Maybe you can just see how well you can balance while touching your nose with your eyes closed.

Good idea on the test, but the problem with such a test would be that old people wouldn’t be able to pass it at noon on a good day. The scary problem with THC intoxication is I haven’t heard of a good test to determine how high you are, so its not only about how high can you get but how long you have to wait, and to what extent you can be prosecuted, etc. Some study like this could essentially make Marijuana smoking illegal for anyone with a drivers licence.

Driverless Cars can’t get here soon enough.


Stress and distraction may be more significant factors.

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To me, that just sounds like you are a bazillion times more likely to fall into highway hypnosis