If you get stopped, you can get screened.
As of December 18th, new laws, put in place by the federal government, dictate that if an officer lawfully pulls you over, they can demand a breath sample. Prior to this, officers had to have a reasonable suspicion that a driver had been consuming alcohol before using a breathalyzer.
From the Government of Canada news release:
“Mandatory alcohol screening will authorize law enforcement to demand a breath sample at the roadside from any driver that has been lawfully stopped. This is a proven traffic safety measure that has had significant success in preventing road deaths in countries such as Australia and Ireland.”
According to the release, the new law will repeal and replace the entire Criminal Code transportation regime. The government expects that the new law will increase deterrence and detection of impaired drivers and simplify the investigation, which will result in shorter trials and reduced delays.