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California Votes On Recreational Pot, Considers Impact Of Driving High

SAN FRANCISCO (KPIX 5) -- Voters will decide whether to legalize recreational pot in California, but what exactly will Prop. 64 mean for safety on the streets?

There's some people who believe driving under the influence of marijuana is not that big a deal. The belief is that people slow down and are thus just not that dangerous.

But Alameda County Sheriff's Dept. Deputy Mathew Neill says, "That is not true at all. I have yet to see someone who drives under the speed limit, 10 or 15 miles under the speed limit, while being under the influence of marijuana."

There is no device to measure breath for marijuana. And blood tests are unreliable.

In Colorado, which already has legalized pot, they do have a blood test. But there's a problem.

Dr. Larry Wolk, Chief Medical and Executive Director of Colorado Department of Public Health and Environment, said "someone can have a 5 nanogram level and not be impaired, somebody can have a 1 or 2 nanogram level and be impaired."

The director of Colorado's public health department says the legal test of 5 nanograms of THC can detect whether someone has ingested weed. It just can't tell when. THC can stay in the human body for weeks.

At UC San Diego, researchers are working on ways to detect whether somebody is driving while high.

Participants either smoke a weak joint, a strong joint, or a placebo, then they get in a simulator.

"You cannot simply take blood, or take saliva right now and say whether or not a person is impaired to be on the road," said Tom Marcotte, co-director of the Center for Cannabis Research. "We're hoping to improve upon that."

Until the science comes along, police are left to conduct field sobriety tests which can look quite different for alcohol and marijuana.

Beau Kilmer, a researcher with the Rand Corporation's drug policy research center, said, "The research is very clear. That driving drunk is worse than driving stoned. However, the bulk of the research suggests that driving stoned is still worse than driving sober."

Kilmer, says if it's legalized, people could choose only to smoke and drive instead of drink and drive, in which case the streets would end up being safer.

But people might decide to mix the two, which could make things worse.

"If we see an increase in the number of people driving under the influence of alcohol and marijuana, we should be worried about traffic safety," Kilmer said.

If Proposition 64 passes, some of the money will fund research that will help answer the question: Who exactly is driving while high?

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