Too High to Drive? How Law Enforcement Tests for Marijuana DUIs

Feb 5, 2018

How does enforcement determine if someone is “too high” to drive?

As scientists try to develop a reliable DUI test for marijuana, KAWC’s Stephanie Sanchez went on a ride along with two local law enforcement agencies who say they just rely on the tools they have. 

DUI enforcement is one of the many responsibilities of Yuma Police Department officer Nick Davis. Late on a Saturday night, Davis spots a traffic violation.

Even before the car pulls over, Officer Davis is looking for signs of impaired driving.

"They're going to take a little while to try to find a good place to pull over, which kind of tells me he’s likely not intoxicated because he is actually using some common sense here," Davis said.

The driver pulls over and Davis walks to the driver’s window. A few minutes later he lets the vehicle go with an equipment repair order for a broken headlight.

"He’s not showing any signs of impairment by alcohol or drugs or anything like that. So I’m just going to basically give him a repair order to make sure you fix your headlight," he said.

This is one of the several stops Davis will make tonight. Each time he’s looking for signs of impairment, and drivers that make the roads unsafe.

“You have the swerving, crossing the center line, the really common things like that or going excessively slow or excessively fast," he said. 

But Davis doesn’t know the source of impairment until he talks to the driver. It could be marijuana or alcohol or something else.

Davis describes the indicators or impairment: "If they have sort of a slower dragged out speech, kind of red or glossy eyes, either like a tired or kind of glazed over look about them."

"If they have sort of a slower dragged out speech, kind of red or glossy eyes, either like a tired or kind of glazed over look about them," Davis said. "If they seem a little distracted, a little not in the situation, maybe excessive laughing or excessively nervous, just somewhat  more emotional one way or the other you would expect on the traffic stop."

Davis said anyone suspected of driving impaired is asked to do a field sobriety test.

If a police officer gathers enough evidence to establish probable cause for an arrest, then the suspect is required to provide a chemical test using a breath, blood or urine sample as required under implied consent laws.

"With all these tests, we have to be certified. At the Yuma Police Department, we don’t traditionally use the urine tests but as far as breath, most of us have operator cards for the intoxilizer, which is also known as the breathalyzer," Davis said. "As far as the blood tests, you need to be a qualified phlebotomist. Which we have several officers qualified in the department but we don’t always have one on duty so depending on the situation we may call one in."

If the driver refuses any tests, then their license is suspended.

But testing for marijuana is controversial. Critics say blood tests used to detect marijuana are flawed because of how long the drug stays in the system. It’s a common concern for medical marijuana users in Arizona.

But Davis said when he’s patrolling he’s less concerned about what impairs drivers than he is about dangerous driving behavior.

"You basically make your decision of whether you suspect this person is DUI or not be it alcohol, marijuana or any other drug. Based on the totality of circumstances," he said.

Law enforcement who patrol interstate roads have the same tools as the Yuma Police Department.

But the Arizona Department of Public Safety is more likely to encounter drivers from California or Colorado, where recreational marijuana is legal.

"Just like alcohol, alcohol is legal if you are over 21, marijuana is legal if you fit the qualifications but you still can't just drive and be impaired by it because you can still get a DUI," DPS state trooper Michael Connor said.

"Just like alcohol, alcohol is legal if you are over 21, marijuana is legal if you fit the qualifications but you still can't just drive and be impaired by it because you can still get a DUI," DPS state trooper Michael Connor said.

More tools to detect marijuana DUIs are on the horizon. But for now, state law enforcement uses the tools available and their training to keep dangerous drivers off the road.

Credit Stephanie Sanchez