Marijuana is top drug used by drivers the WSP pulled over

The Washington State Patrol has significant experience pulling over stoned drivers.

After alcohol, marijuana is the top drug used by people they’ve stopped for impaired driving so far in 2012, followed by methamphetamine and oxycodone.

A few months ago, I wrote about 200 officers in Washington who are trained to know which drug a person is using by observing them – Drug Recognition Experts.

Washington State Patrol Sergeant Mark Crandall is a DRE trainer. In his 20 years as a trooper he’s seen thousands of people who use prescription or illegal drugs, then drive. Some of them are high on a combination of things.

“We find people who are using stuff off the shelf, the huffers, the recreational drug users who take something for a feeling, illegal drugs, the underground drugs, the heroin and meth,” says Crandall. “When you ask what we’re encountering, I always say, ‘What can you imagine?’ It can be anything.”

Crandall and others with the WSP are training to enforce new provisions that come with Washington’s marijuana law.

“We’ve had decades of studies and experience with alcohol,” says Dan Coon, a WSP spokesman. “Marijuana is new, so it’s going to take some time to figure out how the courts and prosecutors are going to handle it. But the key is impairment: We will arrest drivers who drive impaired, whether it be drugs or alcohol.”

Statistics gathered for the National Highway Traffic Safety Administration showed that in 2009, one third of fatally injured drivers tested positive for drugs in their blood.

Crandall says pot can cause dizziness and slowed reaction time, and drivers are more likely to drift and swerve while they’re high.

Unlike portable breath tests for alcohol, there’s no road-side test to determine whether someone is impaired from marijuana use.

The ingredient in cannabis that is most frequently detected in blood tests from impaired drivers is delta-9-tetrahydrocannabinol (THC).

Peak THC concentrations are reached during the act of smoking, and within three hours, they generally fall to less than 5 nanograms per milliliter of blood. That is roughly the same as a .08 limit for alcohol.

According to Washington law, blood tests above 5 nanograms would automatically subject the driver to a DUI conviction.

Under the new Washington law, a pot smoker would cross the limit after two or three hits from a joint, and remain too high to drive for a couple of hours.

Critics say the science around pot-impaired driving is not settled and the National Institute on Drug Abuse says more research is needed to understand pot’s impact on driving.

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By LINDA THOMAS

AP contributed to this report