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DUI Standard in New Washington Marijuana Law May Be Too High: Expert


The threshold for the driving-under-the-influence standard that is part of the new Washington state marijuana law may be too high, a government expert told the Seattle Post-Intelligencer.

Some marijuana users say the standard under the new law—a 5-nanograms-per-milliliter limit for the active ingredient in the drug, THC—is too low, and will unfairly criminalize people who use medical marijuana. However, recent research conducted by scientists from the National Institute on Drug Abuse (NIDA) suggests the standard may be too high to capture drivers impaired by marijuana, the newspaper states.

Marilyn Huestis of NIDA, who conducted a recently published study on marijuana use and psychomotor function, says active THC quickly falls below the 5-nanogram limit within 24 hours. “The level of 5 nanograms per mil is pretty high,” she said. “We know that people are impaired at lower levels than 5, but the balancing act is trying to find a number that can reliably separate (the impaired from the not-impaired), which is almost impossible to do.”

An analysis of nine studies, published last year, found driving under the influence of marijuana is associated with an increased risk of a motor vehicle crash, especially for fatal collisions. The analysis found driving under the influence of marijuana was associated with almost twice the risk of a motor vehicle crash compared with unimpaired driving. The studies in the analysis included nearly 50,000 people.

13 Responses to this article

  1. Michael Pace / September 2, 2014 at 2:43 pm

    “Some marijuana users” think 5 nanograms per milliliter is too low? Like maybe two or three? And how about non-users of marijuana whose IQ is above room temperature?

    That blood level of THC can show up weeks after the last time someone took one puff of marijuana smoke.

    But I guess for people for whom logic and facts are irrelevant, no amount is too low.

    • Geoff / September 16, 2014 at 8:41 pm

      Are you sure it’s THC and not THC metabolites that stay in the system for so long?

  2. Mara / August 25, 2014 at 5:46 pm

    I’m certainly concerned about driving under influence of marijuana. Mostly because in my past I drive a lot after smoking and eating foods with marijuana, as well as friends and family members. We had many close calls, it was only due to the fact that we drove late at night with fewer vehicles that we and others were spared.
    I’m quite upset about the upcoming vote on Oregons law change possible. I’m fine with medical and recreational use, but driving? Just hate the thought of accidents being proven before deciding.

  3. pharmer / July 20, 2014 at 2:40 pm

    I’ve seen tests where regular users of medical marijuana drove better after medicating. When you use it regularly, medical marijuana does not get you “stoned”. Some cancer patients using “Rick Simpson oil”, which has a very high THC content, and who do not like getting “stoned”, begin by using a small amount and gradually build-up to a gram daily WITHOUT ever getting stoned. By beginning with small amounts and building up the dose slowly over time, they slowly develop tolerance to the psychoactive effects of marijuana. While using a gram daily of RSO does not get them stoned, it has a huge amount of THC in it, which would put them way over the legal limit. Having a blood test for THC is illogical and irresponsible: only field sobriety tests make sense. If someone does fail a field sobriety test, THEN test their blood. If they aren’t impaired, it doesn’t matter how high their THC level is. Users of opioid and other drugs should be treated the same way. Even alcohol should be treated that way. Carl Sagen said he used marijuana to help his creativity, as did Dr. Feyman, and they were two of the best minds of the 20th century. I wouldn’t care if teachers medicated on their breaks between classes, because it might make them better teachers. If they get stoned and act like idiots, obviously then it becomes a problem, but that’s true with other drugs they might be using too. People who demonize medicinal cannabis (its proper name) are ignorant and hypocritical if they use alcohol, which is true about 90% of the time in my experience. I’ve been to medicinal cannabis gatherings where experienced users consumed massive amounts of the sacred medicinal herb, and they have intelligent conversations and are well behaved. Alcohol fueled parties are the total opposite: people act like idiots, say idiotic things, and often get violent. If ever there was a drug which should be banned, its alcohol, but I don’t believe it should be banned just because some people abuse it. I was an alcoholic and drug addict in the past, but the medicinal cannabis I use for health reasons also keeps me from drinking and drugging. Rather than discussing what health conditions cannabis can help, it’s easier to discuss what health conditions it doesn’t help, because it seems to help just about everything. Cannabis is the most valuable industrial plant on the planet, and the most valuable medicine and food – that’s why it’s been banned by the evil entity that controls our governments (ALL governments are controlled by the evil entity).

  4. Avatar of Lalo
    Lalo / February 4, 2014 at 8:20 pm

    If our teachers are smoking marijuana, I would doubt their ability to teach much less drive while under the influence. Keep America clean and clear minded.

    • Rebecca / June 24, 2014 at 11:16 am

      That is a fair concern… but what about the myriad of legal prescription drugs and painkillers that people can become easily addicted to? My own grandmother took some form of oxycodone for years and it definitely had an effect on her mental capacity. Anything you say about concerns regarding marijuana has to go doubly for every other substance that is currently legal otherwise you’re creating an absurd double standard for pot. And btw people respond to marijuana in different ways. Sometimes you would never realize a person was high and sometimes they are impaired.

    • pharmer / July 20, 2014 at 2:19 pm

      If teachers are “smoking” (vaporizing is the usual method of medicating NOT smoking) marijuana at night, it will not effect them the next day. If they medicate in the morning and they are regular users, it will not effect them negatively. In fact, it increases creativity, and might make them better teachers. I would much rather have teachers using marijuana than alcohol, which causes nasty hangovers which cloud the mind and make people mean. Regular users of marijuana build a tolerance to its psychoactive effects, similar to how opiate users develop a tolerance. If it’s acceptable to drive using opioids (and it is), than it’s idiocy to make it unacceptable to use marijuana in the same circumstances. People who demonize marijuana are naive and ignorant at best, and usually hypocritical idiots in my experience.

  5. Avatar of Justin
    Justin / January 15, 2014 at 3:01 am

    I think the field sobriety test ought to be the rule of thumb on marijuana DUI’s. Without some common sense on this issue, you will see a sharp increase in productive members of society (mothers, doctors, schoolteachers, etc.) being incarcerated with violent offenders in a for-profit criminal justice system for smoking earlier that day or even yesterday.
    Do you want your child’s favorite teacher, your medical specialist, husband, or disabled honorable veterans to get locked up after a simple speeding ticket because they passed a field sobriety test but failed a blood test? Common sense and education, or chaos and more prisons? Take your pic.
    I thought part of the legalization process was aimed at keeping non-violent offenders from becoming locked up with violent inmates, thus becoming violent by proxy in order to survive. THINK IT THROUGH!
    We have bigger issues and drugs that are killing people immediately. Peace man!
    Disabled Vet

  6. Avatar of jojo
    jojo / January 2, 2014 at 8:30 pm

    Marilyn Houstis study involving 50,000 drivers and the use of marijuana is not about the type of driving practices used, its about people driving careless,the norm (majority of drivers these days)and being stoned. Lets take 50,000 coutous drivers and get them stoned and I bet her study falls apart. This is like the thousands of study’s showing how dangerous teen drivers are but never showing the percentage that even have cars. There are without a doubt more reckless adult drivers on the road than teens, of course! they own more cars and there are more in the 25- 65 age group than 15 teen-24 age but they will never do a study on that. Her study is geared towards the result her funders $$ wanted. Radio down no people in the car (safe following distance)her study falls apart.

  7. Shattah206 / February 1, 2013 at 7:59 pm

    perryrants, I agree with your premise. However the levels you are talking about are for metabolites in urine. The article, and the Washington State law it refers to, are talking about unmetabolized THC levels in blood. Completely different metrics.

  8. perryrants / February 1, 2013 at 2:19 pm

    i see people with 500ng to 950 ng of thc via urinalysis (50ng being the cutoff). and they swear that their last use was a week ago.

    and by the way, even if you need medical mj for your “pain”, you should not be driving after using. it’s has always been against the law to drive taking meds that alter your mental abilities. –read the pill bottle do not drive or operate heavy machinery!!!!

    • pharmer / July 20, 2014 at 2:23 pm

      I agree with disabled vet: field sobriety tests are the only ones that make sense. Some people are impaired after using small amounts of marijuana, because they are not used to it and have no tolerance. Other people who are regular users and consume massive amounts and still be “sober”.

  9. Avatar of mike
    mike / June 10, 2013 at 4:36 am

    I have never in my life seen a pill bottle say do not drive ……every single one I’ve seen say( take care or use caution while driving or operating machinery). And I think they need more research on safe driving limit before anyone is arrested and has their life ruined just because of driving stoned ……the law should have stayed the way it allways was for driving… field sobriety test / motor skills tests

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