Police say they can tell if you are too high to drive. Critics call it ‘utter nonsense’

Haley Butler-Moore sped up to pass a semi on the highway when she suddenly saw the police lights.
She’d left Albuquerque hours earlier, heading to a Halloween party in Denver. Tired from the long drive, she recalled being nervous as she pulled out her paperwork. The trooper asked Butler-Moore to come sit in the patrol car.
“Do you use any recreational drugs?” asked the officer, as captured on the body camera.
“No,” said Butler-Moore.
“OK, because your eyes are saying something completely different. So how much have you used today?”
“None. I’m a little hypoglycemic and nervous.” Butler-Moore, who is a nurse, added: “I take antidepressants. I take acne medications.”
After a roadside test, where the officer said Butler-Moore asked for directions too often and noted that her eyes fluttered at one point, the officer drove her to the Colorado state patrol office in Walsenburg. There police turned Butler-Moore over to a certified Drug Recognition Expert, an officer specially trained to tell who is high and on exactly what drugs.
“I asked her if she would be willing to perform advanced roadside tests with a DRE and (she) was eager to do so,” wrote the arresting officer.
Looking back on that night in 2022, Butler-Moore said she wouldn’t have cooperated if she knew what DRE was or what would happen next.
“I agreed to it, but I didn’t understand that at that point it was already over,” said Butler-Moore.
The DRE officer began a little known, federally funded 12-step assessment that police across the country say helps decide who is unsafe to drive and who ingested exactly which drugs based on a collection of clues gathered by staring into suspects’ eyes, pinching their muscles, taking their blood pressure and watching closely how they walk and talk and balance.
“It’s such utter nonsense,” said Sarah Schielke, Butler-Moore’s attorney in Colorado. “A cop can use it to manufacture whatever conclusion of impairment they want.”
At the police station, the DRE officer, one of more than 8,000 scattered in departments across the country, asked Butler-Moore to recount everything she did that day.
“If there is no impairment, it will come out here,” the officer told her, the entire evaluation recorded on bodycam.
But the officer had concerns. Butler-Moore had put the wrong date, from the day before. That’s because, Butler-Moore said, she didn’t realize it was already after midnight.
“I’m also paying attention to what you are telling me,” said Sgt. Carrie Jackson. “I’m seeing a lack of smooth pursuit, which is horizontal gaze nystagmus.”
That’s the scientific term DRE officers use to describe jerky eye movements. Jackson said she noticed some horizontal twitches, which the DRE training material says could be caused by prescription meds. But she also saw some vertical jitters, which the officer said might indicate marijuana.
If a DRE officer decides that a driver was unsafe at the wheel, that can lead to a charge for driving while impaired and a trip to jail. And in many states DRE officers can testify at trial as a sort of human breathalyzer, stating as a fact that their testing showed someone was on drugs and too high to drive.
The Drug Recognition Expert program helps to convict thousands each year. But a monthslong investigation by MLive and AL.com, involving scores of interviews and reviews of public records and court cases, found:
Proponents say the 12-part screening is the best available tool to catch drugged drivers, as there is no breath test to measure who is currently impaired by something like marijuana. Plus, police have to watch for a nearly endless list of possible drugs.
“Forensic testing cannot test for every substance,” said Jim Maisano, a retired deputy chief in Oklahoma who now coordinates the national DRE program with the International Association of Chiefs of Police.
“They may get a toxicological test back that says no substance found,” he said, and in that case, a DRE evaluation “can help the prosecution with that case.”
But critics say it doesn’t hold up.
William McNichol, a professor at Rutgers Law School with a background in chemistry, has studied DRE.
“It is a classic example of ‘police science,’” said McNichol. “That is to say, it is not science-based at all, but is merely a police officer’s lay opinion encrusted with some of the trappings but little or none of the substance of science.”
Or as Dr. Jeffrey Janofsky, a professor of psychiatry at Johns Hopkins University School of Medicine, testified several years ago during a challenge in Maryland, no medical doctor would use the DRE steps and charts to decide who was on what drugs.
“It’s ridiculous, I can’t emphasize that enough,” he told the court.
Butler-Moore was confused. At first, she thought she had agreed to more roadside tests and she thought she would pass this time.
“I know that I was shivering. I know that’s why I couldn’t walk in a straight line,” she said on the bodycam video. “I’ve been told that I talk at a slower cadence, and I appear high. I also have allergies and my eyes are red. I am not under the influence of any drugs.”
She told the officer she was happy to pay the speeding ticket.
But it was too late. The DRE evaluation doesn’t take place on the side of the road but rather after arrest, usually in a police station, jail or hospital.
“We want to get them out of the elements,” said Sgt. James Janes, the DRE coordinator in Michigan.
First, a breath test rules out booze. The DRE monitors the suspect’s attitude, coordination, speech and eyes. They take the first of three pulse readings.
Next, the eyes are more closely inspected. The DRE looks for involuntary twitches and takes pupil measurements. Suspects undergo the heel-to-toe walk-and-turn and one-leg stand. Additionally, they perform a finger-to-nose test and a balance test, which involves standing still with the head tilted back and silently counting to 30.
The officer records the suspect’s temperature, blood pressure and pulse, all the while checking to see how the results compare to the DRE decoder ring, a chart of drug types and possible physical responses.
They move into a dark room where the DRE pulls out their pupilometer, a card that helps measure the size of the pupils.
The DRE will grab the arms and squeeze, checking muscle tone. “Certain categories of drugs may cause the muscles to become rigid,” the DRE website says. “Other categories may cause the muscles to become very loose and flaccid.”
While checking the arms, the DRE looks for needle marks.
If a suspect has made it this far, said Captain Kelly Waugh in Lander, Wyoming, they’ll often fess up when shown the DRE steps and the results. “It’s human nature,” said Waugh, who worked as a DRE trainer and has been certified since 2007.
A blood sample is drawn and sent for analysis. But that can take weeks, coming long after the trip to jail.
No single clue tips the scale.
“It’s the totality of the evaluation, for sure,” said Waugh. “But if, of the 20 or 30 things you’re looking for, 15 land in (one drug) category, it’s probably that category … that’s why we always do it the same and always do it the same order.”
And the evaluation methods haven’t changed much since being created in Los Angeles in the early 1970’s.
Richard Studdard, known as the “godfather of DRE,” said he made it his mission to stop drugged driving after a fellow LAPD officer was killed in a fatal crash. But there were hurdles. The crime was difficult to prosecute. Doctors were reluctant to offer opinions on who was too high to drive.
“I started training my guys to be experts on drugs,” he told a reporter for this article.
Eventually, Studdard and a former narcotics officer, Len Leeds, created the 12-step process so police could reach conclusions without involving doctors. By 1979, LAPD turned that into a full program with certification standards.
Butler-Moore said she was sober and had not taken any illegal drugs. She passed the breathalyzer – the first of the 12 steps.
Next, Sgt. Jackson took her pulse, checked her muscle tone, measured her pupil sizes and assessed her balance. All the while, Jackson studied Butler-Moore’s eye and body movements for clues of impairment.
But eye movements, and their connection to particular drugs, have come under attack in court cases.
Dr. Frederick Fraunfelder, an ophthalmologist in Missouri, helped defend DRE in New Jersey and said the eye exam is a useful tool.
“Even if they were able to invalidate the eye stuff, it doesn’t invalidate the many other things that are in the exam,” he told a reporter recently. “But I am convinced that eye movement disorders and pupil shape is a valid way to put together the puzzle of whether or not they’re impaired all by itself.”
Fraunfelder said each step of the evaluation is just part of the story — from slurred speech to stumbles to blood pressure. It all needs to be taken into account. “It is a valid tool and it’s a good tool, and it should be a tool that police officers can use,” he said.
“And don’t take it away from them. That’s my opinion.”
But McNichol, who teaches a course on marijuana and the law at Rutgers, said much of the DRE exam does not bear up under examination. Half the country has high blood pressure, pulse rate jumps when a police officer touches someone’s neck, some people are just bad at balancing and doctors don’t measure muscle tone by pinching. He noted that the DRE manual lists normal pupil size as an indicator of marijuana use, when that’s just a normal pupil.
As far as telling who is too high to drive, many of the DRE indicators would be amusing, he said, “if they were not so earnestly offered as based on science.”
There aren’t a ton of studies on DRE. But McNichol poked holes in three older ones often cited by supporters. For example, one 1998 study showed DRE officers guessed wrong half the time. “Not much better than a coin toss,” McNichol said.
More recent studies haven’t been much clearer. In 2023, at the University of California in San Diego, DRE officers attempted to tell who was high on marijuana. Officers labeled half of the placebo subjects as impaired. In another study, at Massachusetts General Hospital in 2022, DRE officers flagged 20% of sober volunteers as stoned.
“There’s several reasons why you’ll see some courts look at studies and say it’s good to me,” said McNichol. “Part of it is that judges aren’t scientists.”
“And an important part of it is that the people that are trying to question DRE accuracy are very, very, very poorly funded. They’re public defenders.”
Even going by the program’s own numbers, it’s difficult to pinpoint how DREs fare against blood tests. Iowa reported 93% accuracy, although representatives didn’t provide a time frame; Wisconsin recorded 93% all-time accuracy over nearly 25,000 evaluations; and Michigan didn’t have a firm number, but the DRE coordinator cited nearly 94%.
But several states responded that they don’t track accuracy.
North Dakota DRE Coordinator Tarek Chase said toxicology tests may not check for all drugs and sometimes suspects refuse testing. Sgt. Dustin Woida, the DRE Coordinator in California, said the state does not compile accuracy numbers. “Furthermore, since we do not own the database, we would not be able to provide such data.”
Still in the police station in Colorado, Butler-Moore said she believed that she needed to remain polite to clear up the misunderstanding and get out of there.
“I told them, ‘Well, I am acutely anxious, so I think that’s reflected in the vital signs,’” recalled Butler-Moore. “And (the officer) told me, ‘You don’t look very anxious to me. You look really calm.’”
Moving through the evaluation, Butler-Moore stood on one leg. But she used her arms and she stepped off the line, the DRE trooper said. Both are listed among telltale signs of impairment. The officer determined her pupils were outside the normal size range and that her pulse was elevated.
The officer reached a medical conclusion: Butler-Moore was impaired on a central nervous system depressant.
And that’s a conclusion a DRE officer can testify to in most courts: This driver was unsafe.
But a legal battle has been raging quietly for decades in courts across America, as defense lawyers have used science to challenge police expertise. They won some challenges, and they lost some.
In Arkansas, Alaska, Wyoming, New Mexico and New York, judges have ruled DRE officers can testify as experts. Yet courts have taken away expert status for DRE officers in several other states, including Michigan, Maryland, Rhode Island, Minnesota and Florida.
“My opinion is that it’s voodoo science,” said Phillip Price, a DUI lawyer in Alabama. “What they’re trying to do is to make it appear like it’s a scientific approach to law enforcement.”
Attorney Evan Levow helped challenge DRE in New Jersey. He told a reporter that the program is “hocus pocus.”
“There are no scientific studies, peer-reviewed or otherwise,” he said, “that say that this is a reliable process not only to establish impairment, but impaired driving.”
The case reached the state’s top court, and the justices asked a former judge, Joseph F. Lisa, to look into the science. Lisa reported that DRE “protocol is based upon methods and procedures that comport with generally accepted medical methods and procedures in identifying likely drug use and the category of the drug or drugs involved.”
In the end, the New Jersey Supreme Court split the difference, allowing DREs to testify as experts, but the police must make a reasonable attempt to obtain matching blood work.
In many states, matching blood work is not required.
And in other states, lawyers have yet to challenge the DRE program.
Meanwhile, police say there is a growing need to be able to identify unsafe drivers. The number of drug-related traffic accidents is rising and about half the states have now legalized marijuana. Police in some states are trying out saliva tests, VR headsets that measure eye movements, and even portable brain scans. For now though, there are no easy answers, no clear alternatives to old-fashioned roadside coordination tests and the DRE exams.
In Colorado, the officer told Butler-Moore that her case didn’t make sense. “I am seeing impairment,” she told Butler-Moore again, but added that her pupils appeared big and her pulse high for a depressant. At one point, she asked: “Have you ever been diagnosed with large pupils?”
It’s not the only odd observation a DRE-trained officer has made. In a Michigan case, a deputy wrote in his evaluation that a woman’s “nasal cavity had less hair than average,” although it’s unclear how he quantified that.
Back in Colorado, the first trooper suspected weed, but the DRE officer seemed to have dropped that theory. Instead, the conversation kept coming back to Butler-Moore’s prescription antidepressants and how a possible double dose might affect vital signs.
At one point, the officer tells her: “You are a nurse, so you speak my language.”
That is where critics draw a line. They say police are not medical experts, and may have borrowed the language without the proper understanding.
While public defenders rarely have the money or time to mount a formidable challenge, a decade ago in Maryland, a group of defense lawyers banded together to bring several key creators of DRE into court.
“(We) just kind of lost our minds about the BS, if you will, that is DRE,” said public defender Alex Cruickshank. “And it took us maybe two years to consolidate 15 or 20 cases before the Circuit Court of Carroll County and have a hearing.”
In one of the cases, police stopped Harvey Carr, then 55, for driving slowly and crossing over a center lane divider in 2010. A DRE officer decided that Carr was impaired on stimulants and narcotics. But the officer failed to account for a traumatic brain injury Carr suffered when he was 10. He was paralyzed on his right side and his speech was slurred.
During the Maryland court proceedings, attorneys called numerous witnesses to testify about the history and effectiveness of DRE, starting with its California origins in the 1960s and 70s when Studdard and Leeds found Dr. Zeon Zuk, then working part time in the Los Angeles jail system.
Zuk, who went on to become a major figure in the history of DRE, first learned the signs of impairment while experimenting on immigrants and working with the U.S. Immigration Service.
“Dr. Zuk sedated deportees with high levels of drugs to obtain their cooperation,” wrote attorney Brian DeLeonardo in a 2011 brief in the challenge in Maryland. “One of the drugs he used was a PCP dissociative anesthetic called Droperidol.”
Zuk stayed involved with DRE for 30 years as a researcher, presenter and expert witness before he died in 2018.
In 1986, DRE moved beyond California with pilot programs in a handful of states, complete with new emblems and ribbons for the officers who completed training.
“Law enforcement is a little like the military: we like little logos and things,” said Thomas Page, one of the DRE pioneers while testifying in Maryland. “I was kicking around some of the things that would go in this logo and it so happens that one of our Drug Recognition Expert officers, his wife was an illustrator for the Walt Disney Corporation.”
The illustrator came back with an eagle clutching twelve arrows and grapes. The arrows stood for syringes and grapes for alcohol. “I took it to a pin company; we did some pins,” said Page. “We did some T-shirts and that’s how it took off.”
Other officers were also called to the stand. Maryland state trooper William Tower II testified that no medical experts contributed to DRE’s development other than one optometrist who, “came to help us look at some of the eye signs and some of the technical part of the curriculum.”
Cruickshank and his fellow public defenders also summoned several medical doctors from Johns Hopkins, one of the nation’s top medical schools, to testify.
One fundamental flaw, Cruickshank’s experts testified, is that DRE-trained officers are not doctors or nurses and cannot rule out a host of other conditions that might cause the symptoms they are observing. Also, they said, drugs affect everyone differently.
Dr. Neal Adams, then an ophthalmologist at Johns Hopkins University, testified that the DRE method for measuring pupil size, one of the key indicators, is inaccurate, and that he knows of nothing that would correlate pupil size to drug impairment. Also, he testified, the DRE range for normal pupil size is too narrow because most people already fall outside of it.
Other experts said the ranges for pulse rate and blood pressure are too narrow. They said the police were using a formula to measure the ratio of the angle of eye twitches to determine particular drugs in a “gross distortion” of medical literature. What’s more, they testified, even if they found someone had taken drugs at some point, there was no way to tell who was still impaired while driving.
“There has not been a single study anywhere either in the non-peer-review literature or the peer-reviewed literature that test the DRE protocol against driving impairment,” testified Janofsky, the professor of psychiatry. “It has not been done.”
In 2012, Maryland Circuit Court Judge Micheal M. Galloway ultimately ruled: “The DRE protocol fails to produce an accurate and reliable determination of whether a suspect is impaired by drugs and by what specific drug he is impaired.”
It seemed like a victory for Cruickshank and the other public defenders, but experts say such rulings in lower courts across the country often pass with little attention, as the DRE program continues to train more than 1,000 new officers every year.
“The police departments tend not to appeal decisions that strike down DREs,” said McNichol at Rutgers, “because they don’t want to give them publicity and they don’t want to get a higher court opinion on that.”
McNichol said the obvious fix is to come up with a valid, scientifically sound alternative, a field test that can measure impaired driving, especially for marijuana.
But today, those tasked with updating the DRE program are often its biggest cheerleaders. Among the 25 people currently listed as members of the committee that sets standards and practices, most are members of law enforcement. That includes DREs, police chiefs, prosecutors and doctors who are either also police officers or who have given expert court testimony on behalf of the program.
The total amount of money spent on DRE is difficult to pinpoint.
The National Highway Traffic Safety Administration spent about $2.2 million on the program in fiscal year 2023, according to figures provided by the agency. That’s in addition to money spent through state grants and support from organizations like Mothers Against Drunk Driving.
Butler-Moore worried about her boyfriend’s 12-year-old son, who had been in the car with her and taken to the police station in Colorado.
By 3 a.m., the DRE officer finally charged Butler-Moore and told her she would go to jail for driving while under the influence of drugs, speeding, following too closely and reckless endangerment of her boyfriend’s son.
A social worker said she would take the boy to a county foster home to await his mother, who was already driving in from New Mexico.
“I’m sorry we didn’t make it to Denver,” Butler-Moore tells the boy, as captured by the bodycam. “I think it’s some of my meds I’m not metabolizing. You can tell all your friends I got arrested and we had a crazy time.”
“Let’s not do that,” said the social worker.
The arresting officer said Butler-Moore was a “nice girl.”
“If I had let you go and something had happened that would have been on me,” she said. “I know it sucks.”
In the end, Butler-Moore failed the test over reasons like the size of her pupils, how she counted to 60, how she talked and the way her arms swung when she walked. The DRE first suspected marijuana, then an overuse of antidepressants. Neither neatly fit the model.
Yet they sent her to jail to detox “… and they didn’t even know why,” said Butler-Moore, looking back. She worried she might lose her job as a nurse.
Contacted about Butler-Moore’s stop, Colorado State Patrol this month said “No such records exist with respect to such person.” Schielke this week sued the two Colorado troopers, arguing they lacked probable cause for the arrest and effectively questioning the way DRE is used in Colorado.
The suit says that it is “common practice” in Colorado to employ DRE methods to arrest “drivers foolish enough to admit any past consumption of their regular prescriptions.”
The suit says Sgt. Jackson was named DRE Instructor of the year by the Colorado Department of Transportation in 2021. “In just a 6-month period in 2022, she conducted 10 DRE examinations and had blood results return in at least 5 of them confirming she had been completely wrong.” reads the complaint.
About five months after the arrest, her bloodwork came back. Colorado confirmed that Butler-Moore was not on drugs, no marijuana, no depressants, no alcohol. “Not even a trace,” reads the suit.
“I just felt like I was another test subject for them,” she said, looking back two years later, “and that felt really unfair.”
Butler-Moore said she tried to cooperate the whole time and perhaps should not have. “Maybe they would have reacted to me differently if I didn’t try to be so nice.”
“It was just really humiliating. It made me really anxious and it made me doubt myself that I had not handled that situation well. But I don’t know of anyone else who wouldn’t be anxious in that position. And especially when they sent me to jail at three in the morning after all of that. It really couldn’t have been worse.”