The launch of legal marijuana in Minnesota is being met with a massive campaign to prevent impaired driving. Public service announcements on TV, radio, and online are all delivering the same message to drivers.

“Driving high is a DWI.”

Yet when it comes to identifying and prosecuting those under the influence, 5 INVESTIGATES found police across the country are still looking for answers.

From Minnesota to Colorado, enforcement of DWI laws where recreational marijuana is legal relies on varying standards for impairment, roadside tests, and drug recognition training that researchers and defense attorneys are now challenging. 

‘A culture shock’

When 5 INVESTIGATES recently traveled to Denver, Sgt. Jason Sparks with the Colorado State Patrol shared words of advice for his fellow law enforcement members in Minnesota. 

“It’s going to be a culture shock,” Sparks said.

The veteran officer became a certified drug recognition expert (DRE) even before Colorado voters legalized marijuana in 2014. He has seen changes on the road ever since.

“It’s almost as prevalent as alcohol,” Sparks said. 

Colorado hopes to eventually double the number of drug recognition experts in the state. 

“We have 120. We could support 250,” said Glenn Davis, Highway Safety Manager at the Colorado Department of Transportation. “We highly recommend it.”

$15 million for DREs

In Minnesota, the legislation that passed in May also included $15 million to train and certify more police as ‘drug recognition evaluators’ or DRE’s.

When a driver agrees to an evaluation, they conduct a 12-step test that includes measuring pupil size, pulse, and muscle tone.

Col. Matt Langer, head of the Minnesota State Patrol, calls the training a ‘critical component’ of the strategy to crack down on impaired driving.

“It’s just someone who’s highly skilled beyond the average trooper, cop, or deputy to recognize not only impairment but what type of drug or drugs someone might be using.”

But 5 INVESTIGATES found drug recognition tests are being frequently challenged by defense attorneys.

“This is pseudoscience cloaked in medical and scientific technology,” said Chuck Ramsay, a well-known DWI attorney from Roseville.

He warns the expansion of DRE’s in Minnesota could have unintended consequences.

“People who aren’t impaired are going to get snared,” Ramsay said. “And that means that innocent people who pose no risk to the public’s safety will be getting arrested.”

Law enforcement leaders insist DRE’s are an effective tool when used in combination with other investigative techniques.

“Our training curriculum is the same for cannabis as it is for alcohol in terms of how you make the traffic stop, identify cues of impairment,” Langer said. “It starts from the very beginning, and we have to build our case.”

Suspicion of DWI

A traffic stop in Owatonna last year is an example of what police could be dealing with more often.

Soon after an officer pulled over a Jeep for no headlights, the officer said he detected the smell of marijuana.

The driver admitted to smoking, but much earlier in the day.

Body camera video obtained by 5 INVESTIGATES shows the officer did not find any pot or paraphernalia, but still arrested the driver for DWI after conducting a field sobriety test. 

Prosecutors dropped the charges more than seven months later after a blood test revealed the driver only had an “inactive metabolite” of THC in his system. 

The active delta-9 THC that makes a person high was “not detected.”

“It doesn’t demonstrate that he’s under the influence of marijuana,” said defense attorney Alex De Marco.

In an email to 5 INVESTIGATES, Owatonna Chief of Police Jeff Mundale said there was still probable cause to make an arrest based on the roadside interview, observations, and the standardized field sobriety testing.

“The challenges for law enforcement officers and prosecutors in marijuana impaired driving incidents and convictions is that that there are no established per se levels of impairment like there is for alcohol impaired driving arrest,” he added.

Impaired Placebos

Researchers at the University of California San Diego recently concluded that the use of field sobriety tests “may be insufficient” to determine impairment from marijuana.

In a recent study of more than 100 volunteers who ingested THC, highly trained officers identified more than 80% as impaired.

However, when the same officers evaluated a second ‘placebo group’ who had not ingested any THC, they still classified half of them as impaired.

“Field sobriety tests are a key component of the gold standard law enforcement officer-based evaluations,” the researchers wrote in the study that was published in August. “Yet controlled studies are inconclusive regarding their efficacy in detecting whether a person is under the influence of THC.”

Preaching Prevention

The challenges around enforcement may be part of the reason leaders continue to preach prevention.

“I’ll be very candid, we’re never going to stop all of these things,” said Davis, the Highway Safety Manager in Colorado.“ But we want to keep the roadways as safe as we can.”

While data shows traffic deaths related to cannabis in Colorado are rising, a defense attorney is dubious of statistics suggesting that more people started driving high after the state legalized recreational marijuana.

“You can really make the stats say whatever you want,” Tiftickjian said. “I think the government is looking for it more.”

But Davis is convinced that legalization changed the culture in the state and has led to more impaired drivers. 

“All of a sudden, that taboo is kind of gone,” Davis said. “The quality of the product is significantly more potent, and it’s easier to get.”

Colorado expanded its DUI task force to include members of the marijuana industry.

“We’ve learned that if we want to reach a customer, it’s point of sale or point of use,” Davis said. “And they can get us into those places.”

At dispensaries such as Native Roots in Denver, customers can find information from the state about impaired driving.

“My hope for Minnesota is to see a partnership between the state, regulatory bodies, and industry to come together to tackle this head-on,” said Truman Bradley with the Marijuana Industry Group, the trade association for marijuana businesses in Colorado.

“This isn’t something where ‘the emperor has no clothes’ and we’re not talking about it,” Bradley said. “We need to address impaired driving.”