9.7Drug Recognition Experts (DREs)¹

A drug recognition expert or drug recognition evaluator (DRE) is a specially trained police officer who is skilled in detecting and identifying persons under the influence of drugs and in determining the category or categories of drugs that caused the impairment.²

DRE testimony is not automatically admissible, and the trial court must still make a determination whether a DRE officer is qualified to offer expert testimony, as outlined in Section 9.6. See People v Bowden, 344 Mich App 171, 175 n 2 (2022) (noting that even if a person’s “certification designates him as a drug recognition ‘expert,’ that label has no bearing on whether he may properly testify as an expert for purposes of MRE 702”).

In Bowden, 344 Mich App at 175-177, the defendant was charged with operating while intoxicated on the basis of marijuana use, and “the prosecution filed a motion in the district court requesting the court to ‘declare [a deputy involved in the traffic stop with the defendant] an expert in the field of Drug Evaluation and Classification be allowed to testify, and provide an expert opinion, as a Drug Recognition Expert.’” The Court held that “the prosecution did not present any evidence in the district court to show that the DRE protocol had been validated as a reliable method for demonstrating a person’s level of impairment due to marijuana or the degree to which a person’s driving abilities could be diminished by any given level of marijuana.” Id. at 189. “The studies on which the prosecution relied demonstrated the DRE protocol’s level of accuracy with respect to determining whether a particular type of substance was present in a person’s blood,” but “the determination under the DRE protocol that a person is ‘impaired’ and unable to safely drive a car appears to be ultimately based on the DRE officer’s subjective judgment, and there is no evidence in this record that the ability of a person to make such a judgment based on the application of the DRE protocol has been tested to demonstrate the accuracy and validity of reaching such a conclusion on a person’s level of impairment due to marijuana.” Id. at 189, 191-192 (holding that the proposed expert testimony was inadmissible under MRE 702 because the prosecution failed to meet its burden to establish the reliability of the proposed expert testimony).

A.Determinations Made by DRE

“A DRE conducts a detailed, diagnostic examination of persons arrested or suspected of drug-impaired driving or similar offenses.”³ “Based on the results of the drug evaluation, the DRE forms an expert opinion on . . . (1) whether or not the suspect is impaired; if so, (2) whether the impairment relates to drugs or a medical condition; and if drugs, (3) what category or combination of categories of drugs are the likely cause of the impairment.”⁴ The process “is based on a complete set of observable signs and symptoms that are known to be reliable indicators of drug impairment.”⁵

B.The 12-Step DRE Protocol

“The DRE’s utilize a 12-step process to assess their suspects:

1. Breath Alcohol Test

The arresting officer reviews the subject’s breath alcohol concentration (BrAC) test results and determines if the subject’s apparent impairment is consistent with the subject’s BrAC. If so, the officer will not normally call a DRE. If the impairment is not explained by the BrAC, the officer requests a DRE evaluation.

2. Interview of the Arresting Officer

The DRE begins the investigation by reviewing the BrAC test results and discussing the circumstances of the arrest with the arresting officer. The DRE asks about the subject’s behavior, appearance, and driving. The DRE also asks if the subject made any statements regarding drug use and if the arresting officer(s) found any other relevant evidence consistent with drug use.

3. Preliminary Examination and First Pulse

The DRE conducts a preliminary examination, in large part, to ascertain whether the subject may be suffering from an injury or other condition unrelated to drugs. Accordingly, the DRE asks the subject a series of standard questions relating to the subject’s health and recent ingestion of food, alcohol and drugs, including prescribed medications. The DRE observes the subject’s attitude, coordination, speech, breath and face. The DRE also determines if the subject’s pupils are of equal size and if the subject’s eyes can follow a moving stimulus and track equally. The DRE also looks for horizontal gaze nystagmus (HGN) and takes the subject’s pulse for the first of three times. The DRE takes each subject’s pulse three times to account for nervousness, check for consistency and determine if the subject is getting worse or better. If the DRE believes that the subject may be suffering from a significant medical condition, the DRE will seek medical assistance immediately. If the DRE believes that the subject’s condition is drug-related, the evaluation continues.

4. Eye Examination

The DRE examines the subject for HGN, vertical gaze Nystagmus (VGN) and [] for a lack of ocular convergence. A subject lacks convergence if his [or her] eyes are unable to converge toward the bridge of his [or her] nose when a stimulus is moved inward. Depressants, inhalants, and dissociative anesthetics, the so-called “DID drugs[,]”[] may cause HGN. In addition, the DID drugs may cause VGN when taken in higher doses for that individual. The DID drugs, as well as cannabis (marijuana), may also cause a lack of convergence.

5. Divided Attention Psychophysical Tests

The DRE administers four psychophysical tests: the Romberg Balance, the Walk and Turn, the One Leg Stand, and the Finger to Nose tests. The DRE can accurately determine if a subject’s psychomotor and/or divided attention skills are impaired by administering these tests.

6. Vital Signs and Second Pulse

The DRE takes the subject’s blood pressure, temperature and pulse. Some drug categories may elevate the vital signs. Others may lower them. Vital signs provide valuable evidence of the presence and influence of a variety of drugs.

7. Dark Room Examinations

The DRE estimates the subject’s pupil sizes under three different lighting conditions with a measuring device called a pupilometer. The device will assist the DRE in determining whether the subject’s pupils are dilated, constricted, or normal. Some drugs increase pupil size (dilate), while others may decrease (constrict) pupil size. The DRE also checks for the eyes’ reaction to light. Certain drugs may slow the eyes’ reaction to light. Finally, the DRE examines the subject’s nasal and oral cavities for signs of drug ingestion.

8. Examination for Muscle Tone

The DRE examines the subject’s skeletal muscle tone. Certain categories of drugs may cause the muscles to become rigid. Other categories may cause the muscles to become very loose and flaccid.

9. Check for Injection Sites and Third Pulse

The DRE examines the subject for injection sites, which may indicate recent use of certain types of drugs. The DRE also takes the subject’s pulse for the third and final time.

10. Subject’s Statements and Other Observations

The DRE typically reads Miranda,⁶ if not done so previously, and asks the subject a series of questions regarding the subject’s drug use.

11. Analysis and Opinions of the Evaluator

Based on the totality of the evaluation, the DRE forms an opinion as to whether or not the subject is impaired. If the DRE determines that the subject is impaired, the DRE will indicate what category or categories of drugs may have contributed to the subject’s impairment. The DRE bases these conclusions on his [or her] training and experience and the DRE Drug Symptomatology Matrix. While DREs use the drug matrix, they also rely heavily on their general training and experience.

12. Toxicological Examination

After completing the evaluation, the DRE normally requests a urine, blood and/or saliva sample from the subject for a toxicology lab analysis.”⁷

C.Drug Categories

“DREs classify drugs in one of seven categories: Central Nervous System (CNS) Depressants, CNS Stimulants, Hallucinogens, Phencyclidine (PCP) and its analogs, Narcotic Analgesics, Inhalants, and Cannabis. Drugs from each of these categories can affect a person’s central nervous system [and] impair a person’s normal faculties, including a person’s ability to safely operate a motor vehicle.”⁸

“1. Central Nervous System (CNS) Depressants

CNS Depressants slow down the operations of the brain and the body. Examples of CNS Depressants include alcohol, barbiturates, anti-anxiety tranquilizers (e.g., Valium, Librium, Xanax, Prozac, and Thorazine), GHB (Gamma Hydroxybutyrate), Rohypnol and many other anti-depressants (e.g., as Zoloft, Paxil).

2. CNS Stimulants

CNS Stimulants accelerate the heart rate and elevate the blood pressure and ‘speed-up’ or over-stimulate the body. Examples of CNS Stimulants include Cocaine, ‘Crack[,]’[] Amphetamines and Methamphetamine (‘Crank’).

3. Hallucinogens

Hallucinogens cause the user to perceive things differently than they actually are. Examples include LSD, Peyote, Psilocybin and MDMA (Ecstasy).

4. Dissociative Anesthetics

One of the seven drug categories. It includes drugs that inhibit pain by cutting off the brain’s perception of the pain. PCP and its analogs are examples of Dissociative Anesthetics.

5. Narcotic Analgesics

A narcotic analgesic relieves pain, induces euphoria and creates mood changes in the user. Examples of narcotic analgesics include Opium, Codeine, Heroin, Demerol, Darvon, Morphine, Methadone, Vicodin and OxyContin.

6. Inhalants

Inhalants include a wide variety of breathable substances that produce mind-altering results and effects. Examples of inhalants include Toluene, plastic cement, paint, gasoline, paint thinners, hair sprays and various anesthetic gases.

7. Cannabis

Cannabis is the scientific name for marijuana. The active ingredient in cannabis is delta-9 tetrahydrocannabinol, or THC. This category includes cannabinoids and synthetics like Dronabinol.”⁹

D.Roadside Drug Testing

“The department of state police may establish a pilot program in [Michigan] for roadside drug testing to determine whether an individual is operating a vehicle while under the influence of a controlled substance in violation of [MCL 257.625].” MCL 257.625t(1).

An officer who is a certified drug recognition expert participating in a roadside drug testing pilot program may use preliminary oral fluid analysis to determine whether an individual is operating a vehicle while under the influence of a controlled substance. See MCL 257.43b.

For a detailed discussion of roadside drug testing, see the Michigan Judicial Institute’s Traffic Benchbook, Chapter 9.