Driving under the influence of marijuana: Bill to set THC blood test passes unanimously in committee

DENVER - A bill to establish a marijuana driving limit test unanimously passed a Colorado House committee on Tuesday, with special urgency now that recreational weed is legal for adults.

A bill approved 11-0 by the House Judiciary Committee after more than five hours of debate would set a blood-level limit for marijuana.

"With the implementation of Amendment 64, the problem is going to grow, so that's another reason we need to get this legislation passes now," said Republican Rep. Mark Waller, the bill's co-sponsor.

Arapahoe County Sheriff Grayson Robinson was among those to testify about the importance of the bill Tuesday. He argued it was a "public safety matter."

Similar proposals have failed three times before because of concerns that blood tests aren't a fair way to tell whether someone is too stoned to get behind the wheel.

"I think there will be a lot of patients risking being falsely accused and convicted under this law," said Teri Robnett, a medical marijuana patient who testified against the bill.

Opponents said there are already laws in place making it illegal to drive while impaired by any drug.

House Bill 1114 would presume drivers are too stoned if their blood contains more than 5 nanograms of THC per milliliter. THC is the psychoactive ingredient in marijuana.

Waller said his bill is different from previous versions because it would allow someone to rebut that they are impaired at the 5 nanogram level.

"For example, if you did not exhibit poor driving, you can put that on as evidence to say, "Look my driving was not poor...I'm not unsafe to operate a motor vehicle," Waller said.

Tyron Link, a medical marijuana user, said her biggest concern was fair testing.

"It doesn't make me impaired now if I haven't smoked since yesterday," he said. "We're not even going by scientific evidence at all. We're just saying. 'Oh lets pick 5 nanograms.'"

KIRO-TV in Seattle recently put three marijuana smokers to the test after Washington state passed a similar law. Each person drove worse as they smoked excessive amounts of marijuana.

One volunteer, who smoked more than a gram during the experiment, admitted at that point she shouldn't have been allowed behind the wheel.