Didn't read the entire thread...
Haven't smoked in something like 6-7 years, haven't even been around it. But when I was younger, I smoked regularly around the ages of 21-24. Not daily, but almost every weekend when I had it and a few times during the week if I didn't have too much school work. Don't drink too much now either. Pretty much a drink occasionally on the weekends type of person now, not even every weekend though.
I definitely smoked and drove at the same time and a lot. But, I do think there's a difference between getting in the car and smoking a joint or two and being completely baked out of your mind and getting in the car to drive. My friends and I would generally smoke a joint or hit the bowl a few times and then get in the car to wherever we were going, getting fast food, a party, the bar, wherever. But, if we were smoking to get baked, we didn't drive. We'd just order a pizza or something and veg on the couch.
I don't condone driving under the influence of alcohol or weed. But, the two are not the same. Yes, at some point, you zone out on weed, but that doesn't mean the OP meant he does that. He could have, but I didn't read it that way. Smoking a joint while driving while you still got your senses and motor skills isn't much different than having a couple beers and driving. Is it right? No. Should people do it? Not really. But, is reality that there are plenty of people that do? Sure. I'm completely against people driving when they're not in position or state of mind to do so. But, I'm also a realist. It happens. Hopefully, the really baked and really drunk people aren't the ones on the roads. But, you have to understand there will be some that have smoked or drunk a few and gotten behind the wheel.