I think the main issue is the lack of accepted safety. I'm in favor of legalizing marijuana, but quite honestly my biggest fear is people operating a vehicle while high because it's okay to smoke it openly.
It's not legal to drive while you are impaired regardless of the reason for the impairment. From a public safety standpoint banning bars would do far more good than legalizing medical marijuana. IMO, it's one of those cases where the perception of risk has little to do with actual risk.
