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THC driving impairment varies widely in upcoming HDNet World Report test

Update below: HB 1261, a bill to set THC driving standards, was put on hold by the Senate judiciary committee last month only to be revived and fast-tracked late in the legislative session. But it died in a Senate vote due in part to the enormous variations in the way marijuana affects different people. And an upcoming report for HDNet World Report is expected to reinforce this argument.

Dennis O'Brien, Denver-based executive producer of World Report, read with interest our post revealing that Westword medical marijuana critic William Breathes's blood test was nearly triple the proposed 5 nanogram per milliliter of blood standard even when he was sober. But O'Brien and his team didn't set out to duplicate this approach for a story currently scheduled to appear on May 17; check local listings for HDNet, which is available on Comcast HD, DIRECTV and Dish Network.

Instead, O'Brien explains, "we tested four people who use medical marijuana for various reasons by putting them in a driving simulator. We did a baseline test of reaction times, then tested them again after they had taken a typical dose of medicinal marijuana."

Mark Ashby, a former law-enforcement pro with experience in recognizing signs of driving impairment, observed the tests. The results?

"We found varying levels of impairment," O'Brien says. "Some drove perfectly well, while one person got into a quote-unquote accident. So there was quite a range even in our small sample."

O'Brien stresses that the experiment "wasn't a scientific test -- it was more of an anecdotal version of a scientific test." However, the HDNet crew used two men and two women of different sizes, ages and typical MMJ consumption to broaden the test's scope.

To O'Brien, the findings "weren't as obvious as you would expect to find if you had four people who were intoxicated with alcohol, where across the board you would have similar reactions. Our admittedly limited sampling seemed to support the idea that people respond to marijuana differently and there's not one way people drive while quote-unquote high."

Senator Morgan Carroll, chairwoman of the Senate judiciary committee that argued for more study of the THC driving limits bill, said much the same thing in an interview prior to HB 1261's death. "With alcohol, the metabolism issues are so well understood that you can give people a rule of thumb -- you shouldn't have more than one drink every x-hour if you're male or female," she noted. "And the members of judiciary kept asking people if there's a way a medical marijuana patient can tell how long after what kind of dosing they'll be okay to drive, and no one can answer that." As such, she concluded that setting a bright-line standard for THC intoxication "isn't ready for prime time."

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As for O'Brien, he says, "All of us know by now people who use medicinal marijuana for very good reasons, so in no way do we want to denigrate people's medicinal needs" with the upcoming HDNet story. "And that's not the debate we're interested in getting into. But I think there are some fascinating questions both in Colorado and other states that have approved medicinal marijuana, whether it has to do with the federal-state relationship and enforcement, whether it has to do with the proliferation of clinics, or whether it has to do with the definition of driving impairment. These are just some of the unintended consequences of medicinal marijuana law."

Update, 1:32 p.m.: Here's a video preview of the report.

More from our Marijuana archive: "THC driving limits could cause more innocent people to spend months in jail, attorney says."

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