The accused was charged with care or control of a motor vehicle while over 80 milligrams of alcohol per 100 millilitres of blood, contrary to the Criminal Code.
Police received a tip that a woman had been drinking all day and was driving to a beer store.
Officers located the vehicle at the beer store and stopped the accused as she reversed out of a parking spot.
The accused failed an approved screening device test and later approved instrument tests at the station.
The defence challenged the lawfulness of the detention under Charter sections 8 and 9, and raised issues regarding compliance with the two-hour requirement under section 258 of the Criminal Code.
The court found that the police had authority to detain and investigate the accused based on the specific information received and the common law ancillary powers doctrine.
The court also found that the Crown proved compliance with the two-hour requirement and that the officer had reasonable grounds for the approved instrument demand.
The accused was found guilty.