Edit: I'm actually saying this as someone who enjoys and actually does bike. When living in the city proper, I think there are very few routes for which the bike isn't the quickest method of transportation. For my commute, which is pretty much a best-case scenario (modern metro with few to no issues, goes in a fairly straight line, don't have to change lines, stations close to both home and the office) the bike is much faster: 20 instead of 30 minutes.