I was in Manhattan last year, and I have to agree: they are a pain. From what I've seen of Manhattan traffic, particularly in midtown, bicycles can operate pretty well there as a mode of transport. They are typically nearly as fast as cars in that environment, and faster on the cross streets. Pedicabs on the other hand, are slow as molasses(If they are lucky, they'll break 8mph--slow enough that even my uberclyde self would be shouting "ON YOUR LEFT!"), and worst of all are as nearly as wide as a car, so they slow down traffic flow in a way a single cyclist never could, actually contributing to congestion, rather than alleviating it. It's like a one man CM ride.