Unfortunately, you really have to separate. The action is not in the blood, so unlike where there's this nice correlation—I'm sure people have said here—with alcohol, it's not the same with cannabis. It gets really complex because chronic users will have chronic levels in their blood. There have been some studies showing some impairments for prolonged times, but really the most significant impairment happens within a few hours or five to six hours, as another one of your witnesses testified. Seeing five nanograms the next day is probably not indicative of cognitive impairment.
On September 25th, 2017. See this statement in context.