For what it's worth, I received my Medical Marijuana Card when I lived in California in 2012. I went to a dispensary in Berkeley to get my first (and as it turns out, only) fill of medical cannabis. It was like a McDonalds of Weed. Different buds in display cases, and LED monitors giving the different varieties with pricing hanging from the ceiling.
In regards to driving, when I bought my weed from this dispensary, they asked me if I had ever purchased from them before. When I said no, they invited me to their hash bar in the back for a free hit of hash. I walked to my car after the hit, and for the next 2 hours I drove around Berkeley in a giant circle, finally pulling over and having to GPS my home address because I couldn't figure out how to get home.
So from my own personal experience, there is a thing about buzzed driving being drunk driving.