After taking the subway home from a show last night one of the first things I saw on the teevee was an anti-drunk driving ad. It occurred to me that in all the years I've been seeing these things I don't remember a single one (I could be wrong!) suggesting people take mass transit instead of driving.
This is an odd mental block to see persisting for so long. I recall seeing one or two ads that involved calling a cab (still not really "mass transit"), but most involve making one friend go to the bar and drink coke all night while everyone else drinks to their hearts' content. The only people I've ever really known who do this effectively and consistently are married couples, probably for various reasons. Back in my rowdier, more single days, DD's were rare indeed.
I know that in both my current and former places of residence the local bus system would occasionally run pub crawl-type services or run buses to the party district, and both have ongoing free rides for students, but there was never much hype about it, and I do not recall any real effort to present the service as an alternative to being DD.
On the other hand, it should be noted that national efforts to combat drunk driving are clearly having some effect, as the number of alcohol-related fatalities has been in steady decline since the 1980's, with steep declines over the last 3 years. Of course, we're still talking about potentially thousands of people every year who die because somebody found carpooling, cabs, and mass transit insufficiently convenient.