I work in downtown Boston and commute from Brighton. I put down "two wheels" because, while I could get there faster in the car most of the time, that would be just driving to the front door of my building, and there is no parking. To actually get to work driving, I would have to drive around the corner (assuming I used the nearest garage) and then walk back. At that point, it would likely be a wash time-wise.

My other option is public transportation, and it's really no contest. My choices there are either a quarter mile walk, wait for the bus, ride the bus in part way, change to the subway, wait for a train, and ride that in...or a half mile walk to take the trolley in all the way. My fastest public transportation commute is about equal to my slowest, lollygagging, going-out-of-my-way-by-two-miles-and-stopping-at-my-favorite-bagel-place bike commute.