Unfortunately, it's not possible to bring a bike into a crowded commuter bus and the stretch between home and bus stop can't be efficiently used by bike without commiting several traffic violations. I can, however, do the entire trip by bike (which I often do in summer), using a different route. That takes only slightly longer than the trip via bus.
In the Netherlands and Denmark, it's not unusal to cycle to a bus stop or railway station, lock the bike there, take the bus/train, and walk at the other end.
Or, to own a second bicycle and leave it at the other end.
In London small, folding bicycles serve the same purpose, but they're much more expensive.
