Municipal, regional and federal police services are responsible for enforcing provincial/territorial and federal impaired driving laws.
Impaired drivers are most often detected at sobriety checkpoints, or during routine traffic stops where police have reasonable suspicion that the driver may be impaired. Increasingly, citizens are also helping police to identify potentially dangerous drivers by calling 911 to report suspected impaired drivers.
The sobriety checkpoint is one of the primary tools which police use to detect impaired drivers. Police set up checkpoints on public roadways and stop all vehicles coming through, enabling the screening of large numbers of drivers.
Generally, drivers are asked whether they’ve been drinking and if so, how much, over what time period etc. Based on any obvious signs of alcohol intoxication and behavioural clues, the officer will demand a breath test* on a breathalyzer device. If the test indicates a ‘warn’ (over .05% BAC) or ‘fail’ (over .08% BAC), the driver may face provincial/territorial sanctions, may be required to do additional testing and/or may face criminal charges. (Only the results of the secondary testing, on an approved screening device, can be used as grounds for a federal Criminal Code charge and as evidence in court.)
*Federal legislation passed in 2018 included a provision for mandatory alcohol screening, which gives police the authority to demand a breath sample from any driver they have lawfully stopped. Learn more about mandatory alcohol screening.
Testing for drugs
While most people think of impaired driving as “drunk” driving or related specifically to alcohol, impairment by drugs is also a serious problem. Various national and provincial studies indicate that driving after drug use is commonplace, and the rate of driving after cannabis use is increasing, particularly among the young.
If police have reasonable suspicion that a driver has drugs in his or her body, they can demand the driver complete a standardized field sobriety test (SFST) or provide an oral fluid sample for testing at roadside. If the driver fails the administered test, the police can then demand a drug recognition evaluation (DRE) by a specially trained officer or demand a blood sample for testing. (As with testing for alcohol impairment, the first screening test done at roadside – SFST or oral fluid screening test – is not evidentiary and cannot be used as grounds to lay a federal Criminal Code charge or used as evidence in a criminal trial.)
Call 911 Programs
Increasingly, members of the public are contacting police to report suspected impaired drivers. Thanks to programs such as MADD Canada’s Campaign 911 and other Call 911 programs, the public is becoming more aware of the signs of impaired driving and what they should do if they spot a driver they suspect is impaired.
Effective 911 programs increase arrest rates for impaired driving by 30% on average.