There have been no studies to correlate the sobriety test roadside to an overall percentage of people who are actually failing the drug evaluation afterwards, because we don't have a presumptive level, as we do for alcohol. We have to go through the whole evaluation, at which point we're 98.6% accurate with the drug evaluation in Canada. So I guess you'd basically look at 1.4% as those who have been brought in and passed.
On June 14th, 2007. See this statement in context.