I do the bike-train thing in Chicago too. Under normal condition I can drive the 21 miles in 45 to 60 minutes and the bike-train takes 1:35 minutes. However, because of road construction driving is more like 1:15 now. Even still I think the bike-train option is more productive. I get a good work out in, I save miles on my car, avoid road rage, and I read a book on the train.