I don't know. I thoroughly enjoy my rather short bicycle commute which happens at an ambling pace of about 10-11 mph on average. It is among the most interesting parts of my day because I see, hear and smell the city from a completely different perspective. Plus, I don't have to be concerned about parking. Perhaps, I've biased myself by also sometimes driving in the Boston area, which is a really mind-numbing experience. Now, if only cycling in the city was a little bit safer, everything would be perfect.