Breathalyzer and Toxicology Results

Breathalyzer and Toxicology Results

Breathalyzer results are one of the most common forms of documentary evidence and are present in virtually every impaired driving case. When an individual is pulled over for suspected impaired driving, they will be given a pass/fail breathalyzer at the roadside. Where the office suspects the accused is impaired by drugs, they may request a roadside impairment test. If the motorist fails the roadside test, they will be placed under arrest and transported to the police station.

At the station, those who failed the roadside breathalyzer test will be required to provide two breath samples to a certified “breath technician”. Those who are suspected of being impaired by drug will be required to provide a blood or urine sample for testing.

A report of the results, known as a ‘certificate’, will be generated, and this report will be entered into evidence against the accused. The Crown may also call a witness with knowledge of the certificate to testify at trial regarding the contents of the certificate and its accuracy. In some cases, an expert witness may be necessary.


Person A is pulled over for suspected impaired driving after he is seen driving erratically by an officer. The officer observes the accused to have red blood shot eyes and the accused is having difficulty answering simple questions. The officer believes he is intoxicated and makes a demand for a roadside breath sample. The roadside breath sample registers a fail, and person A is placed under arrest. At the station, person A provides two suitable breath samples to the breath technician. Both samples prove that the accused is over the legal limit of alcohol to be operating a motor vehicle.

At trial, the Crown will introduce the certificate produced by the breath technician. The Crown also calls the breath technician to testify as a witness at the trial regarding the certificate and its accuracy.  

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