The hazy debate over driving while high is back before Colorado lawmakers as a Senate committee voted Monday to endorse a proposal setting a scientific standard for determining whether drivers are impaired by marijuana.
The bill says drivers would be considered impaired if they test positive for 5 nanograms or more of THC, the psychoactive ingredient in marijuana, per milliliter of blood.
There’s disagreement over whether a blood THC test is a fair gauge of whether a driver is impaired, but a Senate panel voted 4-1 to forward the measure to the full chamber.
“The privilege of smoking marijuana should stop at the vehicle door,” said the bill’s sponsor, Republican Sen. Steve King, of Grand Junction.
Pot activists said they agree driving while high should remain illegal. But some vigorously object to blood testing as a measure of impairment.
Because marijuana chemicals are stored in the body’s fat, levels can build up over time in people who use pot often.
Scientists gave conflicting testimony Monday.
“Nobody in this audience wants to have drugged driving policies, ( but ) there is disagreement about per se limits in chronic users,” said Dr. Paul Bregman, a Colorado physician who recommends marijuana.
However, lawmakers were swayed by conflicting testimony from Cindy Burbach, forensic toxicologist for the Colorado Department of Public Health and Environment.
She told lawmakers that the agency is getting more requests from law enforcement for blood THC tests, from 8,600 requests in 2009 to nearly 10,400 last year.
“Five nanograms is more than fair,” Burbach told senators. She said the department used a different THC screening procedure before 2009, making comparisons before then impossible.