Arkansas voters passed Amendment 98 to legalize medical marijuana in 2016. On May 10, 2019, the first legal purchase of marijuana was made, more than two years after Amendment 98 was ratified. Eight of the 32 dispensaries approved by the state are now open. For the first time Arkansas residents are allowed to possess and use marijuana and cannabis products so long as they hold a state medical marijuana ID card that shows they meet one of 18 qualifying medical conditions approved by the Arkansas Department of Health.

As the industry grows, law enforcement agencies in Arkansas are faced with an unprecedented problem: identifying how much cannabis in a cardholder’s system renders them too impaired to drive. 


While cardholders are legally allowed to possess and use marijuana, they can’t use marijuana in a public place or inside a vehicle and are not permitted to drive while under the influence of marijuana. While police can use Breathalyzer tests to detect how much alcohol is in a driver’s blood at the time of his arrest, no such test exists to immediately determine the degree to which a driver is impaired by marijuana. 

To determine whether a person is impaired by a substance other than alcohol — and to figure out what type of drug is causing the impairment — police departments are turning to what are called “drug recognition experts.” DREs are law enforcement officers who have been trained to observe myriad “indicators” of impairment for seven different “drug categories”: central nervous system depressants; central nervous system stimulants; hallucinogens; dissociative anesthetics; narcotic analgesics; inhalants; and cannabis. DREs include this identification of the drug category in an “opinion” they render after completing a 12-step DRE evaluation process. 


Police departments in every state in the U.S. have DRE programs. Matt Thomas, an officer and drug recognition expert with the Little Rock Police Department, said the LRPD has two DREs on staff — including himself.

Tara Amuimuia, the manager of the traffic safety program at the University of Arkansas System Criminal Justice Institute, is also the coordinator of the state’s Drug Evaluation and Classification Program. Amuimuia, 49, worked as a law enforcement officer for 15 years, and she’s been with the traffic safety program for four years. Amuimuia said officers who go through the DRE program receive training that teaches them to consider a “totality of everything” when determining if, and how, a subject is impaired. Included within that totality is a “drug matrix” of tests and indicators for each of the seven different drug categories. And while an officer who’s been trained as a DRE may employ some of those tests on a subject during a roadside traffic stop, a DRE must process persons who’ve been arrested and brought in to the police station. 


The evaluation a DRE performs is used to “enhance” or “support” the arresting officer’s roadside decision to arrest a subject for impaired driving, Amuimuia  said.

If a driver who has not failed a Breathalyzer test fails a series of field sobriety tests administered by an officer, he or she can be arrested for driving while impaired and brought in for an evaluation by a DRE. But the administering of a DRE evaluation depends on the availability and proximity of a DRE; some departments may allot one DRE-certified officer to every shift, while other departments with fewer DREs, like the LRPD, would have to call for a DRE to come to the station to perform the evaluation. 

The program has been criticized as too subjective and a burden on persons suspected of being impaired. Melissa Fults, executive director of the Drug Policy Education Group, an Arkansas nonprofit that advocates for medical marijuana users and marijuana policy, takes issue with the program’s reliance on the judgment of both the arresting officer and the DRE in evaluating impairment. Despite a complex “matrix” of tests and indicators, the findings of a DRE evaluation still ultimately rest on the officer’s “opinion” of the arrestee’s state. 

“The biggest problem that I have is these [officers] are supposed to be trained to spot someone that’s under the influence,” Fults said. “Yet, in other states … there have been police officers [who] have just gone crazy. They arrest people because they assume that they’re using something, and then they get there, they do the drug test, and they’re fine. But still, they’ve been arrested, they’ve been handcuffed, they’ve been inconvenienced, they’ve been taken to jail, all because someone has the opportunity to say, ‘Oh, I think you look like you’re on drugs.’ ” 


The ACLU of Georgia brought scrutiny to the program in 2017 when it filed a federal lawsuit on behalf of three plaintiffs, all of whom were arrested by a Cobb County police officer, Tracy Carroll, for driving while impaired by marijuana. Carroll attributed his actions during the arrests to his DRE training. All three people were charged with DUIs and spent the night in jail, and in all three cases, the DUI charges were dropped after blood tests showed no traces of marijuana in their systems. But Thomas and Amuimuia said even the results of toxicological examinations may not definitively indicate the status of a subject’s impairment. Amuimuia said it can sometimes take “weeks or months” for an officer to get toxicology results back in a case because of understaffed and backlogged state crime labs, and Thomas said the tests performed can be limited in what they indicate. 

Officers can require a suspect to provide a urine sample for a toxicology screening, but Thomas said this test only indicates if a subject has “recently used” marijuana within a certain number of days; it doesn’t indicate how impaired they were by the drug at the time of their arrest. The officer said blood tests can be more effective at determining the amount of marijuana present in a subject’s system at the time the blood was drawn, but unlike a urine screening — which is considered to be a “noninvasive” procedure — if a subject refuses to take a blood test, police can’t draw blood without a warrant signed by a judge.

Thomas and Amuimuia said the potential delays and limits of toxicology tests are part of what makes a DRE evaluation so useful to a case. Thomas emphasized that police receive extensive training before they become officers in how to conduct a traffic stop when they suspect a driver is impaired. They’re taught to use a “three-step process” before and during a traffic stop, the first of which begins with an officer’s initial observation of a subject’s driving — have they crossed the double center line multiple times? Are they swerving repeatedly? The second step is the officer’s “personal contact” with the driver after pulling him or her over. Thomas said a suspect’s behavior when they’re first pulled over during the stop can help indicate whether the behavior was a “fluke” or a sign that they’re too impaired to drive. 

Sometimes, Thomas said, it is a fluke. 

“Life happens, and it’s part of that full three-step investigative process. I stop people all the time [and] think that they may be impaired to begin with, and they’re not. They’re messing with the radio, they dropped a cigarette, they dropped their phone [or] their kids are yelling at them,” Thomas said. 

If the officer has decided that the driver may be impaired, he’ll ask the driver to exit the vehicle and perform a series of field sobriety tests, including the “one leg” test that checks a subject’s balance, the “walk and turn” test that checks a subject’s ability to walk in a straight line, and the “finger to nose” test that also checks for balance and the speed of a subject’s body movement. 

If after the tests the officer determines that a subject is too impaired to operate his vehicle, the officer can arrest the driver for driving while impaired, just as an officer can arrest someone he suspects of being under the influence of alcohol who has refused to take a Breathalyzer test. The driver is then brought back to the station, where he’s charged. If a subject takes a breath test at the station and registers a low BAC — the state’s legal limit is .08 — or no BAC at all, a drug recognition expert is called in to help ascertain how a subject is impaired. 

The drug recognition expert then performs a 12-step DRE evaluation, a process that Amuimuia said usually takes at least an hour to complete. It begins with an interview of the arresting officer about the traffic stop, along with observations of the “suspect’s attitude.” The DRE then performs several tests, including some of the same field sobriety tests an officer would have conducted, and looks for different indicators to help determine by what drug a subject has been impaired. The DRE will also test eye movement to see how well eyes are tracking;  examine pupil size — dilated, undilated or “constricted” pupils indicate reactions to different drug categories — and the reaction of a subject’s pupils to different degrees of light. DREs also take a subject’s pulse rate, blood pressure and body temperature. 

Drug recognition experts say there are identifiers unique to each drug category: “drowsiness” for central nervous system depressants; “grinding teeth” for stimulants; and “debris in mouth” and “increased appetite” for cannabis, among many others. 

After the tests are complete, a DRE then renders an opinion as to which drug category a subject’s impairment falls. 

The DRE’s opinion is intended to help corroborate the arresting officer’s decision to charge the subject with driving while impaired. 

“It’s kind of like icing on the cake,” Amuimuia said. “You have a cake and you know it’s pretty good, but wouldn’t it be better with icing?” 

“We actually teach that part of it, that not everybody you’re going to evaluate is going to be impaired, that there are medical conditions that do mimic drug use,” Thomas said.


The DRE program was developed by the Los Angeles Police Department in the 1970s to help aid in the arrests of subjects were who impaired, but not by alcohol. 

“Officers were getting a lot of DWI arrests where the BAC was really low or nonexistent, but they knew the person was impaired,” Amuimuia said. “So they figured it was drugs, but they didn’t have a way of figuring that out or proving that.” 

Amuimuia said the LAPD worked alongside psychologists and medical doctors to develop the program. In the early ’80s, the LAPD partnered with the National Highway Traffic Safety Administration to make the DRE program “standardized” throughout the U.S., and Amuimuia said it then expanded nationwide toward the end of the decade. 

The first DRE school hosted at the UA Criminal Justice Institute took place in March and April 1995. Amuimuia said 543 officers have gone through the program since then; 137 officers are now certified in the state, and nine others are candidates for certification.   

The International Association of Chiefs of Police is the accrediting organization for the program. In the document Amuimuia submitted to the IACP for its 2018 annual report, she wrote that 257 “enforcement evaluations” were performed Jan. 1-Dec. 31 in Arkansas, and 71 “training evaluations” were performed — these are evaluations performed by DRE candidates during their training, often on volunteers or persons already in police custody who agree to have an evaluation performed by a DRE candidate. Of those combined 333 evaluations, 129 of the “opinions” rendered by DREs cited central nervous system depressants as the drug category in which the impairment fell; 66 of the opinions cited cannabis as the drug category. 

Bill Sadler, a public information officer for the Arkansas State Police, said 17 state troopers are up to date on their DRE certifications. (Officers must update their certification every two years.) 

Thomas said he “can’t remember the last time” he was called in to perform a DRE evaluation by the LRPD. He said the frequency of a police department’s use of DREs, as well as the number of officers within the department who become DREs, depends on the resources and priorities of the department. 

“Are we putting all of our eggs in the basket of working DWIs? Or are we putting our eggs in the basket [of] working violent crimes?” Thomas said. “Little Rock has a very high violent crime rate, and that seems to take more precedence than getting guys certified as DREs.” 

A department’s funding can also affect how many officers it sends to receive DRE training, as costs for travel and lodging for the duration of the training can mount. Too, when officers are sent to receive training, that means fewer people on patrol or in the office at their home departments. 

The first thing DRE candidates do is “preschool,” Amuimuia said, to learn the seven drug categories and undergo tests to ensure they’re “proficient” in field sobriety tests. Amuimuia said the drug categories in the DRE program differ from those of the American Medical Association and the Drug Enforcement Administration, because the drug categories the AMA and DEA use are “based mostly on chemical structure,” while the DRE program categorizes drugs “based on the impairment they produce.” 

“The definition of a drug is different because, for example, a doctor thinks aspirin is a drug, and it doesn’t impair you — it hopefully fixes your headache,” Amuimuia said. “Whereas somebody huffing spray paint, that will impair you, so that’s one of your inhalants. We consider it a substance that, when taken into the human body, can impair the ability for a person to operate a vehicle safely. So there’s quite a few things on the list that a doctor wouldn’t consider a ‘drug.’ ” 

After the “preschool,” officers take an entrance exam that they must pass by 80 percent in order to move on to the next phase, an intensive 7-day school. In this phase, candidates learn how to do the 12-step DRE evaluation process, and more about the seven drug categories and their indicators. 

After the 7-day school, candidates must pass another 100-question exam by at least 80 percent. The officers then move into the “field certification” portion of their training, during which they have three months to complete 12 different “training” DRE evaluations, each of which must be witnessed by DRE instructors. These training evaluations can be completed on persons who’ve been arrested. The DRE program at the Criminal Justice Institute also offers “mandatory evaluation nights,” during which people volunteer to be evaluated. Amuimuia said these volunteers can include community members who take prescription medication and volunteer to be evaluated by a candidate, or arrestees already being held for a DWI who are offered “snacks and a soda” in exchange for agreeing to be evaluated by a trainee. The mandatory evaluation nights allow candidates to complete a few of their 12 required evaluations under the gaze of DRE instructors in one evening, an opportunity that Amuimuia said helps candidates complete their training. 

A “final knowledge” exam is required for certification. Thomas said it took him 6 and a half hours to complete his entirely hand-written exam. Candidates are required to fill out a blank version of the “drug matrix” from memory, as well as answer multiple choice and fill-in-the-blank questions. 

Though drug recognition experts emerge from their training armed with hours of curriculum and evaluations, critics of the DRE program say the process is a pseudoscience, not grounded in medical or scientific knowledge. 

Both Amuimuia and Thomas said this criticism ignores the intensity of the DRE training and the fact that DREs are taught to take “all factors” of a subject’s arrest and evaluation into consideration. 

“Until [critics] come see the process and understand what we do, they’re going to be clueless,” Thomas said. “We’re not trying to convince people that we’re always right, because we’re still human, we still make slight errors. But when we do our DRE evaluations, we look at everything involved, and that’s what we preach and preach and preach — that it’s not just one or two aspects of it, it’s every aspect of it.” 

Amuimuia echoed this sentiment. 

“Most people that I talk to who think it’s ‘voodoo’ — they like to use that word — they didn’t go through the class,” Amuimuia said. “Unless they’re taught exactly how to do it and what they’re looking for and why they’re looking for that, and that it’s backed by medical science, you’re gonna have your naysayers. Let’s put it this way: I haven’t had any DREs that went through the program and then just quit being a DRE because they didn’t believe in it.” 

Another criticism of the DRE program is that it leaves too much power in the hands of an arresting officer, whose sole judgement about the state of a subject’s impairment dictates whether or not that subject will be arrested, even if they pass a Breathalyzer test on the roadside. Thomas said that though a DRE taking advantage of his or her authority and training is “rare,” he understands the impact such misuse can have, referencing the “case law” of the Georgia ACLU lawsuit. 

“There are officers out here that take their training and go rogue with it,” Thomas said. “Police officers do it, I can’t say that everybody’s perfect. But I do know our program, I do know the people that work for the DRE program in Arkansas, and I know the instructors. And that is the one thing that we push on the instructing side of it: Your reputation goes over not just you, but the whole DRE program. Let’s face it, case law can screw it up for everybody. One bad case law, and everybody’s behind the eight ball.” 

As of Aug. 16, Arkansas has issued 19,227 medical marijuana ID cards to qualified patients and caregivers. Three of the state’s five cultivation facilities are growing, processing and selling marijuana to the eight dispensaries open; the other two cultivation facilities and many more dispensaries are poised to open by the end of the year. As of Aug. 13, the eight dispensaries combined have sold almost 730 pounds of marijuana, bringing the state’s burgeoning medical cannabis industry to $5.28 million in sales.