Just flipping thru the channels on TV and caught an episode of Top Gear on BBC America. It featured a race from the West End of London to an airport on the East side, directly thru the heaviest traffic. There were four modes of transportation: a bicycle (Specialized Sirrus.... neat...fast) , a heavy BMW SUV, public transportation and a speedboat (up the Thames.)
The bicycle wins a minute or two before the speedboat (which maneuvered at speeds of up to 70mph). The guy in public transportation arrived about 10 minutes later and the SUV arrived dead last, 15 minutes later.
So we have it... proof!