And something else: The shift to embrace public transit appears to have a generational component. Younger people are waiting longer to get their driver's licenses, studies show. Many of these folks are using public transit.
Millennials, age 18 to 34, like McWilliams are more likely to use public transit than older Americans, according to surveys.
"Our parents moved to 'burbs where we grew up riding around in cars," McWilliams said. "My generation is going the other way. It may be as simple as that."