[Superman]

If reason prevailed, it would be interesting to point out that in order to establish the level of intoxication, it would be necessary to determine at least one thing. The level of impairment when X-amount of MJ is found in the blood. Significantly, the research is not conclusive, and the powers-that-be have not made an informed "determination" of how much BAC is indicative of intoxication.

When urine is used, another link would need to be shown, and that is the link between urine content and BAC (and therefore intoxication). Nevertheless, law enforcement and employers and insurance companies are busily making these "determinations" by pulling them out of their asses.