I used to ride the bus every day in high school. I enjoy the theory, but the smell of it (you guessed it... URINE!) bugs me to no end.
Though, I give four stars for the super cool driver who gave Theresa B. and I a free ride when she busted a flat on our bike ride from PHX to Tempe for Tour de Fat this year. He got off the bus and helped us put our bikes on, too! Totally cool!