Bus stops are, in some locations, clustered together into transport hubs allowing interchange between routes from nearby stops and with other public transport modes to maximise convenience.The three black rails that run along the sides and back of the bus are called rub rails. Each bus has them and here's why. First, they're an extra layer of protection for the thin walls of a school bus. They'll absorb the force of a collision and a car from caving in the whole side of a bus.