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A Drug Recognition Expert (DRE) is a police officer trained to scientifically identify if a person’s ability to operate motor vehicle is drug impaired by or impaired by alcohol. They are scientifically trained to determine if a person is driving under the influence of drugs. The RCMP and other Canadian police agencies use Drug Recognition Experts for investigations of drug impaired driving.

What is a Drug Recognition Expert? And how do they operate within Canadian alcohol impaired driving and drug impaired driving investigations and what training do they receive?

This Article will discuss these questions with the hope that, if you are stopped by the police in Ontario for an alleged driving while impaired by alcohol or drugs and encounter a DRE, you will understand what is happening and why.

The Role of the Drug Recognition Expert

Drug Recognition Experts were introduced in British Columbia in 1995, but the first program in North American was started in Los Angeles, California. The program provided to be very successful in Los Angeles it was model in other jurisdiction quickly. The program was thought to be so useful that the Government of Canada revised the Canadian Criminal Code in 2008 to implement the program throughout Canada. New impaired driving laws allow police agencies to use a DRE to determine if a drivers ability to drive is impaired by drugs or alcohol. Other revisions included allowing DRE officers to request blood samples to confirm their opinions.

Under the current legislation if the police attend an impaired driving scene the suspect can be evaluated by a DRE officer at the police station.

The acronym DRE is often used interchangeably to refer Drug Recognition Experts and to he examination they perform, the “Drug Recognition Examination” or “Drug Recognition Evaluation.” Now some police services the term Drug Influence Evaluation (DIE) for the evaluation done by officers. A copy of the standard form used during the drug recognition elevation is available for download here.

The Supreme Court of Canada in R. v. Bingley, 2017 SCC 12, held that a DRE is a “drug recognition expert”, and is certified as such for the purposes of the 12 step evaluation. By reason of his training and experience, a DRE undoubtedly possesses expertise on determining drug impairment that is outside the experience and knowledge of the trier of fact. He is thus an expert for the purpose of applying the 12 step evaluation and determining whether that evaluation indicates drug impairment. His expertise has been conclusively and irrefutably established by Parliament. Knowledge of the underlying science is not a precondition to the admissibility of a DRE’s opinion.

What Is Drug Recognition Evidence?

The Drug Recognition Expert considers established “drug recognition evidence” in his or her evaluation of impairment. They will assess blood pressure, pupil size, conducted divided attention tests all to determine the categories of drugs.

This evidence is both physiological and behavioral. The DRE will administer a 12-step standardized test to determine if you are impaired.

This 12-step test enables the DRE to examine your physical and chemical indications of impairment, as well as your ability to respond to guided interview questions.


All DREs follow the same 12 step procedure called a Drug Influence Evaluation (DIE), to determine which category of drugs is the cause of the impaired driving. The 12 steps of the DRE standardized procedure are:

  • Breath test to rule out alcohol impairment. If the subjects impaired driving is consistent with that of a drunk driver and they have a high concentration of alcohol on their breath the officer will not engage or call a DRE.
  • Interview of the arresting officer for details of your behavior.
  • A preliminary physical examination, including a pulse check.
  • Eye examination.
  • “Divided attention tests,” in which the ability of your eyes to converge is evaluated.
  • Blood pressure and temperature examinations, as well as a further pulse check.
  • Examination of your pupil size and nasal and oral cavities in a darkroom.
  • Muscle tone evaluation.
  • Physical examination for injection site evidence.
  • A personal interview and evaluation of your statements.
  • 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 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.
  • Toxicological examination: After completing the evaluation, the DRE normally requests a urine, blood and/or saliva sample from the subject. The toxicological sample is sent to a Government of Canada certified forensic laboratory for analyses to confirm 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.

If a DRE determines that the suspect was driving under the influence and was too impaired to safely operate the vehicle, they will look for indications of the suspected drugs by the common effects that drugs have on the human body. There are seven categories of classifications a DRE is looking for, including; central nervous system depressants, CNS stimulants, inhalants, dissociative anesthetics, narcotic analgesics, hallucinogens, and cannabis.

Conclusion: Ontario Drug Impaired Driving and Drug Recognition Experts

The overall purpose of the DRE examination is to evaluation whether the presence of any drug in your system, as further evidenced by your behavior, amounts to drug impairment.

The presence of a drug in your body will not support a criminal charge alone.

If you have been charged with an impaired driving offense, it is crucial that you contact an experienced Ontario criminal defence lawyer to review your options—and the process followed by the DRE during your examination.

Contact us now to schedule your free consultation.

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