I think that it might hold, at least for me. The biggest obstacles to my use of public transportation is the first mile and last mile, and the regularity of trips.

Using Google Maps as my source, a trip home will take between 1hr, 3min to 1hr, 30min, and still includes driving for the last mile. Granted, this is San Antonio, which is certainly a driving city. The same drive home is 14-17 minutes, depending on route.

In my calculus, drive vs. public trans. is a balance of which sucks least. Right now, I would say that the cost and altruism aspect of public trans. would allow it 200% of the suckiness allotted to driving. All else being equal, I would need a public trans. trip of ~30minutes or less.