‘It’s junk science.’ Michigan court case sets precedent for so-called drug ‘experts’

JENISON, MI — Cara King needed smokes.

Before she hopped into her aunt’s silver Mazda 6 to head to the gas station, the 27-year-old took a hit of marijuana.

While it’s been legal to smoke marijuana in Michigan since 2018, it is still illegal to drive while high.

But police don’t have a perfect system for determining that – and what happened next to King would have a lasting impact on how counties across Michigan prosecute motorists suspected of being too stoned to drive safely.

Her court case raised questions about the validity of Drug Recognition Experts (DRE), a decades-old, national program that has trained officers to become “experts” at detecting impairment from drug use.

King and her attorney would fight back – and ultimately set a new precedent in the courts.

“I have a real problem with the science behind the DRE,” said Chris Langholz, King’s attorney. “It’s junk science and it shouldn’t be used to convict anybody.”

The traffic stop

King — who changed her name from Bowden when she married in August – spent years struggling with drug addiction, hard stuff like heroin and meth.

By December 2020, when she went out for cigarettes, she was making positive changes – an 11-month jail stint and three months in rehab behind her, newfound dedication to her son, a steady job managing a McDonald’s, a supportive boyfriend and a hard-fought commitment to never use hard drugs again.

“I’ve got it totally under control now,” King, now 31, told MLive more than three years later. “But it was scary. There was a time when I didn’t think I’d come out on the other side. A lot of my friends are dead.”

As she was headed to the gas station that day, King peered across an intersection at a police car. She was instantly nervous, a symptom of too many past run-ins with the law. When the light switched to green, she pressed the gas.

King didn’t know why at the time, but the Ottawa County sheriff’s patrol car with two deputies inside, made a U-turn and flicked on the flashing overhead lights. King pulled into the parking lot of a liquor store.

A deputy wrote in a report reviewed by MLive that King was stopped for having only one working headlight. Ottawa County deputies didn’t have body or dashboard cameras to record King’s stop, so a recounting of the traffic stop is limited to written police reports and her memory.

“I told Cara that I could smell marijuana in the vehicle, and she told me the last time she smoked was two weeks ago,” the deputy wrote. “Cara’s eyes were bloodshot red, which is consistent with consumption of cannabis. A strong odor of marijuana could be smelled from Cara’s driver-side window.”

A deputy ordered King from the vehicle and started field sobriety tests, noting that King started walking before he finished giving instructions during the walk-and-turn test. She stopped walking at times to steady herself, failed to touch her feet together as instructed and used her arms for balance.

“They kept telling me that my eyes were glazed over, that I was shaking and that I was obviously looking nervous,” King said. “But it was very cold and I had nothing on but a sweater.”

The temperature was just above freezing, 33 degrees, according to weather records.

Deputy Adam Schaller, a certified Drug Recognition Expert, arrived at the scene. Schaller was specially trained to identify who is impaired and on what.

“After more questioning, Cara eventually admitted to smoking a half hour prior to the stop,” one of the other deputies wrote in the police report. “Cara also stated that there was marijuana in the vehicle.”

Police reports said she told deputies she smoked “a bowl,” but King said it was only “a hit” of her bowl and they recorded her statement incorrectly.

At 10 p.m., deputies arrested King on suspicion of driving while impaired on drugs and drove her to a hospital for a blood draw, after which Schaller conducted his DRE evaluation.

What is DRE?

In 2023, there were 8,264 DREs like Schaller who conducted 24,625 evaluations nationwide, according to report data from the International Association of Chiefs of Police, the organization that oversees the national program. Michigan’s nearly 125 DREs conducted 849 evaluations in 2023, said Sgt. James Janes, the DRE coordinator for Michigan.

For nearly a half century, DRE officers helped fill the gap when it came to drugged driving, offering opinions on levels of driving impairment that likely helped convict tens of thousands of people across the U.S.

While alcohol has an accepted and well-studied limit for use before it impairs – .08 blood-alcohol – and machines to test it, the same doesn’t exist for marijuana or most other drugs. Instead, Michigan and states around the U.S. depend largely on the determination of so-called experts like Schaller.

The DRE uses observation, interviews, pupilometers, thermometers and blood pressure cuffs to test balance, cognition, blood pressure, eye movement, pupil size, temperature and muscle rigidity to determine when someone is high, on what type of drug and if they can safely drive.

More: Police stuck with old, imperfect tactics to decide who is too high to drive

They write a report and could be called as an expert witness to share their findings in court. The DRE opinion is usually accompanied by the results of a blood test.

“Most of our officers are in the 94% correct-call (range), so if I said it was a stimulant, there was a stimulant there 94% of the time,” said Janes. “The evidence a DRE collects should be able to stand on its own (in court) but the prosecutor and the jury really want to see a positive result that goes along with what the DRE says.”

Opponents call the method junk science riddled with arbitrary decision-making that’s left up to the officers. There are no boxes to check or quantifiable instructions regarding how much weight should be given to which observations. Medical experts have questioned the ranges for pupil size and pulse rates, have argued that drugs affect different people differently and that no medical doctor would use this technique to figure out who took what.

Yet it remains one of the only ways police have at their disposal to combat drugged driving.

In King’s case, blood tests were no help. She registered 5 nanograms per milliliter of active THC and 37 nanograms per milliliter of metabolites, but she told MLive that she didn’t feel impaired. Multiple studies have concluded the mere presence of THC in the blood is a poor indicator of driving impairment because it spikes quickly and the remnants are expelled slowly, often well after the high has worn off. Furthermore, blood tests don’t take tolerance into account, which means a regular user could register high levels in the blood but feel little to no impairment.

Since blood tests couldn’t confirm impairment, the DRE opinion was crucial.

“It is my opinion as a Drug Recognition Expert that Cara Christine Bowden (King) is under the influence of cannabis and unable to operate a motor vehicle safely,” Schaller’s report concluded.

The precedent

The prosecution in King’s case planned to use the DRE evaluation and opinion, as the prosecution would normally, to prove she was impaired.

But Langholz, her attorney, challenged whether the DRE should be recognized by the court as an expert. That expert status, in a courtroom, makes a big difference. Any officer could testify to what they observed. But as an expert, a DRE officer could go a step further and link their observations to a conclusion. That means Schaller could go beyond saying King was shivering or shaking, and instead testify that she was impaired.

DRE methods have been put to the legal test in numerous other states, such as Maryland, where defense attorneys argued the approach was developed without proper medical guidance by people unqualified to determine how drugs affect the body. DRE witnesses have also lost their “expert” status in other states, such as Maryland, Minnesota and Rhode Island. That means they can testify to their observations, but can’t definitively tell a jury who is impaired and by what drug.

In Michigan, courts were asked to rule on whether the DRE program is reliable, for what purpose and if the reliability has scientific backing.

In order to be proven guilty, prosecutors had to show not only King had consumed marijuana – which she admitted smoking and blood tests proved — but that it impaired her ability to drive in a “normal manner.”

Prosecutors and Schaller pointed the courts to two studies, neither recent. In a 1984 study, back before the program reached most states, DREs identified the correct drug class that caused intoxication nearly 92% of the time. Schaller also testified to a 1985 study that accurately identified marijuana use through the DRE process with a 78% accuracy rate.

But King’s attorney argued those studies answer the wrong question. Langholz instead presented a study of his own, one produced by the National Highway Traffic Safety Administration (NHTSA) that funds the national DRE program that Schaller and the prosecution were touting.

The 2017 report sent to Congress said research shows marijuana has the potential to impair driving, but conceded: there are “currently no evidence-based methods to detect marijuana-impaired driving.”

While two lower courts ruled in favor of accepting DRE testimony as expert opinion, a three-judge Michigan Court of Appeals disagreed.

In a unanimous opinion, the court said: “There simply is no evidence in this record to support that the DRE protocol can reliably be used to detect the degree or level of intoxication caused by marijuana and determine whether that level of intoxication has made the person unable to safely drive a motor vehicle.”

What does it mean now?

The legal wrangling not only impacted King’s personal life, but formed legal precedent in Michigan restricting how Drug Recognition Experts may testify in court.

Defense attorneys in Michigan agree this ruling limits the value of DRE testimony. However, whether the same logic applies to other drugs evaluated by DREs remains yet unchallenged.

Prosecutors think the impact will be minimal.

DREs explain to juries from the stand or in police reports “those physical manifestations that are indicative of certain drug classifications,” said St. Clair County Prosecutor Michael D. Wendling, of the state Prosecutor’s Association. “In light of the King case, we can still use that evidence, that person can still testify … I just don’t believe they can say, ‘I’m an expert, I will ultimately tell you that this person is unable to drive.’ That ultimate conclusion has to be left to a jury.”

Wendling called it a “step back from where we were” but he hopes it will have a minimal impact on prosecutions.

“We’ll continue to use the evidence that’s out there,” Wendling said. “If you’re pulled over and you have powder cocaine all over the front of your shirt, that doesn’t necessarily prove that you’re under the influence of cocaine, but it’s an indicator that you might be.”

Illegal drugs, like meth, heroin and cocaine, often have zero-tolerance limits established by law, making the blood tests alone adequate for conviction. Any presence in the body, by law, constitutes criminal impairment, Langholz said.

King’s case was eventually kicked back to the lower court, where she pleaded guilty to reckless driving as part of a deal with prosecutors that didn’t involve a driver’s license suspension, her greatest concern.

She never expected her seemingly run-of-the-mill traffic stop to have a lasting impact on what police can testify to in Michigan courtrooms.

“It feels pretty good,” King said. “It’s kind of like I am a test case.”