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.

17 Responses

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    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.

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    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

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    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.

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    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.

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    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!!!!

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