When I was young, I was in a small town in California, with a 21 drinking limit.
We did not drink then drive..we drank while driving, on the nightly cruise. It was very commonplace.
Over the couple years I engaged in this "social" activity, followed by years in the military, I can say I have had huge amounts to drink then driven afterwards. I have never received a ticket while drinking, nor been in an accident while drinking.
I was lucky.
Looking back, its a miracle to me that as young and drunk as I often was (and the group of people who were also doing it), that there were not many accidents and fatalities.
Nowadays, I seldom drink at all. And if I do have more than a single dinner cocktail, I would not consider driving at all. Its not worth the risk, not just to me, but to everyone else on the road.