[WS:] I live in Silver Spring and work in Baltimore and I do not have a car - I take transit. More specifically, RideOn bus to Silver Spring Metro, Metro to Union Station, MARC to Baltimore Penn Station, and bus to JHU. It takes me about 1 hr and 40 minutes in the morning and about 2 hours in the evening. Driving took me about 1 hour. The big difference is that this 1 hour was not just a waste of my time but very stressful - DC has one of the most aggressive assholes behind the wheel ;). On the train, it is mostly reading, doing some work, or relaxing.
So it is possible to take transit even if it takes longer. More to the point - it is about time use, planning, and desirability of avoiding contacts with people who look different than oneself rather than just technical aspects of transit vs. driving.
Wojtek