THC driving bill may be hard to kill despite iffy science, senator says
Last April, a bill to set THC driving standards was put on hold by a senate committee -- and a DUID-marijuana working group charged with reconsidering the issue deadlocked over the question of per se standards. But now, Representative Steve King has spoken publicly about resurrecting the measure, and Senator Morgan Carroll, who opposes the concept, feels it may gain traction despite questions about the science on which it turns.![]()
Representative Claire Levy sponsored last year's bill, which established THC intoxication at 5 nanograms per milliliter of blood. Levy later decided this standard was too strict, and suggested that an 8 nanogram limit be substituted, but she didn't win this argument. The 5 nanogram version subsequently passed the Colorado House.
But following a report that Westword medical marijuana critic William Breathes's blood had tested at nearly three times the legal amount while sober, the aforementioned senate judiciary committee shelved the proposal pending future study, and an attempt to resurrect it again in May failed.![]()
William Breathes getting his blood test.
Months later, a divided DUID-marijuana working group failed to come to a consensus, with half the members in favor of a per se limit and the other half arguing that unlike alcohol, THC tends to linger in users for longer periods of time, making it next to impossible to determine actual impairment via a blood test, at least under currently available technology.
That apparently hasn't dissuaded King.
After multiple interview requests from Westword over the course of several days, he eventually sent an e-mail that read, "No thank you on your offer for us to speak on possible proposed legislation," explaining that "time is short."
Yet somehow, King found a few minutes to chat with the Denver Post about the subject, announcing that "quite frankly, I think it's time we cleared the smoke out of this. If you drive high, it's against the law, it puts people's lives at risk, and you should deal with the consequences of making that bad decision." He added that he has not decided whether to promote a 5 nanogram limit or lobby for zero tolerance -- meaning that any trace of THC would demonstrate impairment under state law.
Steve King.
This makes no sense to Carroll, who spoke out against Levy's measure last year. In her view, either a per se or zero tolerance approach will basically make it illegal for any MMJ patient to drive in the State of Colorado even if he or she hasn't recently medicated. But she also feels that defeating such a bill "is going to continue to be an uphill battle" due in part to possible political maneuvering on the part of proponents.
Page down to read more of Carroll's thoughts on the bill and its future.

































