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Overdrive Extra

Max Heine

Scientific American weighs in on driving while stoned

| May 23, 2013

Last fall, readers sounded off on upcoming proposals for legalizing marijuana for recreational use in Washington, Oregon and Colorado. A majority of those who responded favored some form of legalization.

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In an OverdriveOnline poll, 56 percent of respondents said pot should be legalized nationwide for any use.

Washington and Colorado voters approved the measures in November. It’s expected other states will eventually follow suit, considering that marijuana for medical use is legal in 18 states and the District of Columbia.

One of many thorny issues associated with more liberal treatment of pot is driving safety. While there is no push to allow commercial drivers to hit the road while stoned, it’s still worth noting what research shows on marijuana and highway safety.

A recent Scientific American article says “studies indicate that the drug slows reaction time and impairs distance perception behind the wheel. Despite such evidence, most new marijuana regulations, for medical or recreational use, fail to account for these potential risks.”

Some studies try to link certain blood levels of THC (marijuana’s active ingredient) with alcohol blood levels, based on tasks such as changing lanes and braking response. A reasonable idea, but also a problem because a breath test won’t detect THC levels and a warrant is often required for a blood test.

And, on another note, if you’re wondering why weed gives users the munchies, or why mundane things are so hilarious during those first minutes of a good pot high, Scientific American does a nice job of explaining in simple terms what goes on with those whacked-out neurotransmitters.

  • Ron Palmieri

    Active ingredient testing should only be considered for impairment. Even with that, minimum standards could still be considered safe. I don’t believe depth perception is affected, however reaction time may suffer some. Considering many folks bad driving habits around trucks…its totally miniscule in comparison….just my personal experience. 3.1 million miles…0 injuries.

  • Joe

    I believe the issue is more with unfortunately use within the time your body takes to naturally cleanse itself. I would never drive while stoned, or impaired/altered. But, when I am off work, I see no reason why I couldn’t take a bong hit or two. My body cleans itself in roughly 7 days, so it is real hard to fail a urine test. Reason being, I work a couple weeks, without ever using it or alcohol, use possibly up to a gram while I am off work for a week. Then don’t when I go to work, up to 3 weeks, depending on freight volume. DOT sees my red eyes, and searches my truck constantly. Only because I have truck driver eyes. I find that ridiculous, especially for a dot alcoholic who most likely drives impaired from the police bar, every night after work. True, they are safety officials, and can do whatever they please without recourse. I would like them to actually test it, not read statistics before passing judgement on anyone. But also, no, they should not allow operation of heavy trucks after its use either. It should be allowed when you are done driving, only. Hell, you’ll probably miss your exit or interchange anyway…

  • John Aalborg

    Because of how it is done, reaction time testing for drivers using pot is irrelevant. As an old hand who goes back far enough to the times when marijuana suddenly became part of the new “War on Drugs”, I can say from personal experience that when “high”, a driver sees adverse situations coming sooner. A bigger picture of danger up ahead and to the side is also unfolding more slowly but getting earlier attention. I also remember back when police were told how to spot a potential driver on weed. “They drive slower.” As old timers all knew back then, and the current generation should know now, alcohol makes drivers reckless and unreasonably self-confident, and marijuana more cautious. Hearing is more acute, also, and little things beginning to go wrong with anything on the tractor get the driver’s attention sooner. I could go on….

  • John Hill

    Should drive high, save that for home time.

  • Steve Collins

    Marijuana is not good for your body health; it affects your
    kidney and often leads to deadly diseases like cancer.

  • NormlDude

    As an educated cannabis advocate, who does not partake, but plans to when I retire some day, I personally would not condone recreational use by commercial drivers who currently drive. Medicinal use with a 10 hour wait period prior to driving could be an exception, but would be impossible to regulate since cannabis remains in your system for en extended period of time and is no indicator of current influence, or any potential impairment. I will say that California “authorities” conducted research in the mid 1990’s which actually indicated that driving improved under the influence of cannabis, and thus the research was not widely published due to public policy. I wish I could provide a link, but after a brief search, I could not find current reference. I was involved with a national cannabis organization at the time, prior to the passing of Prop 215, and this was a genuine study…I’m not just blowing smoke (pun intended). I will also say at the time the research surprised me, due to the time response factor that I assumed would exist, however, I believe the conclusion was that drivers were more alert/aware and took extra precaution to drive safely during the study. Food for thought.

  • NormlDude

    Found something national…an NHTSA (US DOT, Nov 1993) study, “Marijuana and Actual Driving Performance,”
    concluded that the adverse effects of cannabis on driving appear
    “relatively small”. The
    study (conducted in the Netherlands) examined the performance of drivers
    in actual freeway and urban driving situations at various doses of
    marijuana. It found that marijuana produces a moderate, dose-related
    decrement in road tracking ability, but is “not profoundly impairing”
    and “in no way unusual compared to many medicinal drugs.” It found that
    marijuana’s effects at the higher doses preferred by smokers never
    exceed those of alcohol at blood concentrations of .08%, the minimum
    level for legal intoxication in stricter states such as California. The
    study found that unlike alcohol, which encourages risky driving,
    marijuana appears to produce greater caution, apparently because users
    are more aware of their state and able to compensate for it (similar
    results have been reported by other researchers as well). Note: The NHTSA study also
    warned that marijuana could also be quite dangerous in emergency
    situations that put high demands on driving skills.

  • ZigZag

    ZIGZAG-This is a subject that has been debated for a very long time. I personal feel that we in the trucking industry have alot greater issues to be concerned with at this time. LIKE CARB and the bullshit our goverment is tring to pull on us. strives to maintain an open forum for reader opinions. Click here to read our comment policy.