THC driving test on HDNet shows marijuana impairs, but does it prove anything? (VIDEO)

On Monday, we previewed HDNet World Report's driving test of medical marijuana patients.

The full report aired last night; watch it below. But while it's a respectable piece of work, the final results, which tilt toward the argument that MMJ patients shouldn't drive after medicating, raise more questions than they answer due in part to the small number of participants and the way in which the test was conducted.

The package begins with stoner movie clips from Cheech and Chong and others before rolling into interviews with the likes of attorney Sean McAllister, who has no problem with a per se THC limit from a philosophical standpoint but believes current science hasn't established the sort of bright-line standard in use to determine alcohol impairment.

The report also notes that the Colorado legislature killed a THC driving bill earlier this month because representatives weren't convinced that the proposed 5 nanogram per milliliter of blood standard effectively demonstrated impairment -- particularly in light of a blood test involving Westword medical marijuana reviewer William Breathes, who registered at nearly triple the limit when sober due to the way THC lingers in a user's system.

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The second half of the report concentrates on the test itself. In our preview piece, HDNet executive producer Dennis O'Brien said four people took part in the experiment, which required them to use a driving simulator while sober, then do so again after medicating; in both cases, they were observed by a drug recognition expert. However, only three individuals made the final cut -- and one of them didn't medicate prior to his second try on the simulator, as a way of establishing that the expert, who'd been told that all three smoked, wouldn't see marijuana impairment when none existed.

The person who steered clear of marijuana entirely passed the test both times. Not so the two patients who medicated. One of them got into a virtual, car-flipping accident the second time around, while the other had a couple of incidents when she drifted out of her lane. In both instances, the expert considered them impaired.

Problem is, the test appears to have been conducted immediately after consumption -- so it doesn't provide any insight about whether time might diminish impairment. Moreover, the viewer isn't told how much marijuana the test takers consumed or its potency, leaving the inaccurate perception that all cannabis is the same. And even though the difference in post-medication driving results involving the two marijuana smokers -- lane drifts versus a car flip -- seems significant, the determination that both were impaired seems to more or less shrug off the distinction.

The report concludes with the claim that people on both sides of the driving-on-medical-marijuana issue believe more testing is needed. However, that may not be true for Colorado Attorney General John Suthers, whose attack on the THC driving bill's death, which is mentioned in the HDNet offering, suggests that his mind is well and truly made up on the subject.

See the entire segment below.

More from our Marijuana archive: "Medical marijuana: THC driving limits sponsor voted for one standard, prefers different one."

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