This may be old news to some, but my friend in BC informed me tonight that the police in various parts of Canada have begun issuing blood tests to drivers suspected of being high. Such blood tests also reveal past drug use, of course, not just impairment while driving. If you refuse to surrender your bodily fluids to the state, you'll pay a $1,000 fine.
This is already taking place in Quebec and British Columbia, but since it's federal law, I'm sure it will gradually spread nation-wide.
Source article here.