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Colorado Legislature Gears Up to Debate Drugged Driving Limits


The Colorado legislature is gearing up to debate where to set the limit on how much marijuana can be in a person’s system before they are considered to be driving under the influence, according to The Denver Post.

The debate is likely to include evidence from two conflicting studies, the article notes. An analysis of nine studies, published in the British Medical Journal, 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.

A second study suggests marijuana-limit laws do not impact traffic fatalities.

The debate on drugged driving laws comes in the wake of Colorado’s passage of a recreational marijuana law in November. Currently it is illegal to drive while under the influence of marijuana in Colorado, but prosecutors must prove impairment in every case, the article notes.

One bill that will be considered by the legislature sets the marijuana limit at 5 nanograms of THC—the active marijuana ingredient—per milliliter of blood. Under the bill, a person with at least 5 nanograms of THC would not automatically be convicted, and could try to argue that they were not impaired, even if they hit the 5-nanogram limit.

Recent research conducted by scientists from the National Institute on Drug Abuse (NIDA) suggests the 5-nanogram standard may be too high to capture drivers impaired by marijuana. Marilyn Huestis of NIDA, who conducted a 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 recently told the Seattle Post-Intelligencer. “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.”

6 Responses to this article

  1. DocG. / February 16, 2013 at 4:04 am

    I seriously doubt that highway law enforcement will find many social marijuana smokers out driving around. There might be passengers smoking but the driver…..I doubt it. It is much nicer to toke a joint and have some munchies while watching TV. Any comments on that?

  2. doogiem / February 12, 2013 at 4:01 pm

    Great comments. Hopefully, Colorado and Washington will hash it out (pun intended) so other States won’t have to. That, or other States will review and make corrections.

  3. Abu Muusaa Merrick Abd Al Khabir ibn Wiliam McMillion / February 12, 2013 at 10:38 am

    Greeting all,
    this is a nice study which needs further research. I am an Addiction counselor in one of Colorado’s Detox centers and We find this a nuisance during busy times. due to the fact that some Client’s contacted under this Duid really does not present any signs of intoxication so we have to due what is called a brief assessment which takes alonger then an actual intake admit.

    I am not a proponent of any intoxicants and really its is the responsibility of the individual to make sure the are safe to drive . but a few question jump up. in Colorado Medical cannabis is prescribed just like pain medication and benzo – psychotropics. so how will the Client be protected if they are contacted on a traffic stop ( broken headlights, tags, tints, did not signal etc ) I am not speaking about careless driving stops. and submit to a blood draw and these medications are in their systems? so will this be a just system? We know these medication stay in the system for a while and build half life so what do my comrades in the addiction field feel about what I have posed?.

  4. Shattah206 / February 11, 2013 at 4:07 pm

    5 ng/ml is not the cutoff for pre-employment testing. 50/15 (initial & confirmation tests) are the standard levels, and those refer to urine testing of metabolites. Colorado, and Washington, are discussing levels of active THC in blood. These are completely different metrics, and no comparison can be made between them.

    As for cannabis and mental capacity, during the acute intoxication phase there’s really not much difference between stoned and stupid.

  5. joebanana / February 11, 2013 at 1:53 pm

    5 ng/ml is the cutoff for pre-employment screening, and is meaningless as far as “impairment” is concerned. Cannabis doesn’t turn people retarded like alcohol does. What about prescription drugs? Some of them cause way more impairment than cannabis. “We know that people are impaired at lower levels than 5″, what level of stupid causes impairment?

  6. Avatar of Tom
    Tom / February 11, 2013 at 11:45 am

    What we will need is an inexpensive and effective field sobriety test for THC (and other intoxicants) done during the traffic stop. There really isn’t one now and the alternative is an arrest, a trip downtown and a warrant to take a blood test.

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