The Immediate Roadside Prohibition regime became effective September 20, 2010. The police, not without their own failings, would determine the fate of any individual pulled over, or otherwise detained, to blow into a roadside screening device. Police officers’ reports of what took place at a roadside stop would fundamentally serve as the basis for implementing these penalties under the new regime. Now, three years after the regime was implemented, thousands of drivers have been subjected to the serious penalties mandated by the IRP scheme, and drivers, who formerly would have been dealt with under the criminal system, and many others besides, are now being subject to IRPs instead.
See Kevin Filkow’s full paper on BC’s IRP drinking and driving laws.