You’re waiting for a bus. You wait, and then you wait some more. Finally, two or three buses show up at once, all headed for the same destination. Public transportation professionals have a term for this — several, in fact: bus bunching, clumping, convoying, piggybacking, or platooning. Banana bus is another bit of jargon for this situation, because the buses are all in a bunch.
This is part of a complete episode.