Almost all jurisdictions have taken advantage of the 1954 invention of Robert Borkenstein (1912-2002) which measures the amount of alcohol in a known quantity of breath, from which can be reliably calculated the amount of alcohol in blood. The novelty of Borkenstein's invention was that it contained a complex measuring device into a package simple enough for a busy police officer to use with high accuracy and little training.
Breath is extracted from the subject into the device and alcohol ratio of the breath analyzed. Scientists such as Borkenstein have established a ratio which is used to multiply the alcohol in the breath to calculate the alcohol level in the blood, and thus a level of alcohol and relative intoxication.
The results are then admissible as evidence of impairment subject to challenges related to the administration of the test, the functioning of the device or the handling of the breath sample or results.
The word Breathalyzer® is trade-marked but is commonly used as a generic noun as Kodak used to be used to refer to a photograph and Xerox to a photocopy.
The breathalyzer provides scientific evidence of intoxication and addresses the notorious unreliability of human observation in regards to alleged impairment.
Further, practised alcohol consumers, or alcoholics, are self-trained to conceal signs of impairment, which are noted by breathalyzers without regards to conduct.
As Justice L'Heureux-Dubé wrote in Bartle:
"The breathalyser is simply a device which records a certain state of impairment. It is designed to replace potentially less accurate observations of police officers and to facilitate the work of police officers. In addition, it reduces the costs associated with the presence of police officers in court.
"... Breathalyser results are indicia of a physical condition which existed independently and which could in fact be observed by police officers and recorded by them."
The term breathalyzer is not to be found in the Criminal Code as it refers to a particular brand. Instead, the generic term approved screening device is used, defined as:
"... a device of a kind that is designed to ascertain the presence of alcohol in the blood of a person."
REFERENCES:
- Lucas, D., "The Breathalyzer: How It Works", Chapter 24 of Breathalyzer Law in Canada (Toronto: Carswell, 2009), page 24-1.
- Martin, D., Robert F. Borkenstein, 89, Inventor of the Breathalyzer, New York Times, August 17, 2002
- R v Bartle (1994) 3 SCR 173