When I stop cars now, I ignore the odor of marijuana in the car unless I look the person im out with up and determine they have a history of larger possession amounts (PWISD or higher).
My bad experiences with the County DA's office has me in a position where I would rather ignore all drug possession laws then try to enforce them.
Pretty much, where I work, the substance has to fall off of you on camera (true story for one of my cases) before it will be bothered with in court.
Of course, I always ask if there are any weapons or drugs in a car on a traffic stop, one time this 18 year old stoner actually told me there were drugs in the car... I kinda felt I had to send a message that the cops actually care (even though I don't) and searched his car, found the dope, and wrote him a ticket for it, added to his speeding charge, and sent him on his way.
Other than that, **** marijuana laws, bigger pain in the ass then they are worth, for something I could care less about anyways.
Now, if the mother ****er is high and driving around, then we have srs bidness.