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Drug Recognition Expert (DRE)

Oklahoma DUI Lawyer, C. Jeffrey Sifers has been trained as a DRE

A Drug Recognition Expert or drug recognition evaluator (DRE) is a person trained to recognize the impairment of drivers under the influence of drugs other than, or in addition to, alcohol. 

What does a DRE do?

A DRE conducts a diagnostic examination of a person arrested or suspected of driving a motor vehicle while drug impaired.  The DRE forms an opinion based on the results of a drug evaluation formed from the following:

1.  Is the person impaired?  If so, is the person able to operate a motor vehicle safely?  If the DRE concludes that the person is impaired;

2.  Is the impairment due to a sustained injury, or an illness, or does the person have a medical condition; or is it drug related?  If the DRE's opinion is that the impairment is due to drugs;

3.  In which category, or combination of drug categories. does the source of impairment lie?

There are twelve (12) steps of the Drug Evaluation Process.

1. Breath Alcohol Test

The arresting officer reviews the subjectís breath alcohol concentration (BrAC) test results and determines if the subjectís apparent impairment is consistent with the subjectís 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 subjectís 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 subjectís health and recent ingestion of food, alcohol and drugs, including prescribed medications. The DRE observes the subjectís attitude, coordination, speech, breath and face. The DRE also determines if the subjectís pupils are of equal size and if the subjectís eyes can follow a moving stimulus and track equally. The DRE also looks for horizontal gaze nystagmus (HGN) and takes the subjectís pulse for the first of three times. The DRE takes each subjectís 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 subjectís condition is drug-related, the evaluation continues.

4. Eye Examination

The DRE examines the subject for HGN, vertical gaze Nystagmus (VGN) and a for a lack of ocular convergence. A subject lacks convergence if his eyes are unable to converge toward the bridge of his 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 subjectís psychomotor and/or divided attention skills are impaired by administering these tests.

6. Vital Signs and Second Pulse

The DRE takes the subjectís 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 subjectís pupil sizes under three different lighting conditions with a measuring device called a pupilometer. The device will assist the DRE in determining whether the subjectís 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 eyesí reaction to light. Certain drugs may slow the eyesí reaction to light. Finally, the DRE examines the subjectís nasal and oral cavities for signs of drug ingestion.

8. Examination for Muscle Tone

The DRE examines the subjectís 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 subjectís pulse for the third and final time.

10. Subjectís Statements and Other Observations

The DRE typically reads Miranda, if not done so previously, and asks the subject a series of questions regarding the subjectís 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 subjectís impairment. The DRE bases these conclusions on his 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.

Nothing in or about the DRE protocol is new or novel. The DRE protocol is a compilation of tests that physicians have used for decades to identify and assess alcohol- and/or drug-induced impairment.  See source Link:  http://www.decp.org/experts/

7 Drug Categories:

Physicians have long recognized that different types of drugs affect people differently. Nonetheless, drugs may be categorized or classified according to certain shared symptomatologies or effects. The DRE categorization process is premised on these long-standing, medically accepted facts. 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 an impair a person's normal faculties, including a person's ability to safely operate a motor vehicle.

(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 or dissociating the brain's perception of the pain. PCP and it's 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.

Source Link:  http://www.decp.org/experts/

If you have been accused of Driving Under the Influence of Drugs (DUID) in Oklahoma, Oklahoma County, Oklahoma City, Norman, El Reno, Cleveland County, Logan County, don't delay your defense.  The Prosecutors of the state of Oklahoma are preparing their case AGAINST you.  Let's beat them to the punch and prepare your defense NOW.  Call


Oklahoma DUI Attorney

C. Jeffrey Sifers

Court Plaza Building, Suite 950

228 Robert S. Kerr

Oklahoma City, OK  73102


(405) 232-3384


(888) OKLA-DUI

(888) 655-2384










Oklahoma DUI Lawyer

Jeff Sifers


Time is wasting!