Good questions. Like I said I am not a legalization advocate, just kind of meh on the issue.
Employees have a right to fire potheads and legalization does not change this. No illegal is not the same as a civil right. Driving: is there any way to test for pot intoxication? It stays in your system for like a month from what I understand so a positive urine test is pretty meaningless. But yes, driving high is like driving drunk.
As for the association with criminals, I think it is a case of correlation not meaning causation. Potheads are generally harmless while high, they just sit there, babble nonsense, and stare at their hands. It is just that the kind of people who commit crimes are also the kind that often smoke weed.
Heavily used by mohammadens in Afcrapistan and ME and everywhere in the violent regions of Africa.
Offer the driver a doughnut from outside the window and measure how far they reach out for it. The farther the reach, the more loaded.