Skip to content

DRE: The Drug Recognition Expert Protocol

The drug recognition expert protocol, or DRE, is a standardized and systematic method of examining if a suspect is driving under the influence of drugs.

When a police officer suspects that a person is impaired by drugs he or she will conduct a series of standardized field sobriety tests to determine if there are probable grounds to conduct further testing.

The DRE will determine the following:

  • whether or not the suspect is impaired, and if so whether the impairment relates todrugs or a medical condition, and
  • if drugs what category or combination of categories of drugs are the likely cause of the impairment.

The systematic process is based on a complete set of observable signs and symptoms that are known to be reliable indicators of drug impairment.

The Drug Recognition Expert (DRE) uses a 12 step procedure in performing the evaluation. These steps are:

1.Breath alcohol tests

The arresting officer reviews the subjects breath alcohol concentration BRAC tests to rule out alcohol as the primary cause of impairment. If the impairment is not explained by the BRAC the officer will request 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 will ask the officer about the subjects behaviour, appearance, and driving.

3. Preliminary examination and first pulse

The DRE conducts a preliminary examination 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 subjects health and recent ingestion of food, alcohol, and drugs, including prescribed medications. The DRE will observe the subjects coordination, speech, attitude, breath and face. The DRE also determines if the subjects pupils are of equal size and if the subjects eyes can follow a moving stimulus and track equally. The DRE also looks for horizontal gaze nystagmus hdn and takes the subjects pulse for the first of three times. If the DRE believes that the subject may be suffering from significant medical condition the DRE will seek medical assistance immediately. If the DRE believes that the subjects condition is drug-related the evaluation continues.

4. Eye examination

The DRE will examine the subject for horizontal gaze nystagmus (HGN), vertical gaze nystagmus (VGN), and a lack of convergence.

5. Divided attention psychophysical tests

The DRE will now administer four psychophysical tests: the modified Romberg balance, the walk and turn, the one leg stand, and the finger to nose test.

6. Clinical indicators examinations

The DRE will then take the subjects blood pressure temperature and second pulse.

7. Darkroom examinations

The DRE estimates the subjects pupil sizes under three different lighting conditions with a measuring device called a pupilometer. The device will assist the DRE in determining whether the subjects pupils are dilated, constricted, or normal. Nasal and oral cavities may also be examined at this time.

8. Examination for muscle tone

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

10. Subject statements and other observations

The DRE typically reads Miranda if not done so previously and asks the subject a series of questions regarding the subjects 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 subjects impairment.

12. Toxicological examination

After the evaluation the toxicological sample is sent to a forensic laboratory for analyses to confirm or refute the findings of the evaluator. The mere presence of a drug in the sample does not constitute sufficient evidence to charge a person as being impaired by a drug. The evaluation must show impairment signs and symptoms consistent with one or more drug categories and the evaluators findings must be supported by the toxicology.

Make sure you have all the facts.

For more information and helpful safety hints visit, Aitken Robertson criminal lawyers.


Recent Videos


CALL US TODAY AT 1-800-668-1657