This is just kinda cool, from Brazil, an idea for having a pedal-power assisted bus. Via Inhabitat, we learn that there is a design from "Rever Design Studio for a cycling double decker bus. On the second level, there are 24-27 active passenger cycles to assist in generating the power reserve of the electric bus. The lower level of the bus is for passive passengers and a bus driver. The double decker bus also comes with a back room for more than 30 folding or non-folding bicycles."
I think that this could be an interesting way to travel around Rio. (The question is, though, whether people would prefer to pedal on a bus or pedal alongside and between them...)