Here, all new busses are equipped with a display indicatind the next station. Some of them use information provided by infrared beacons and incremental encoders but the newer ones use GPS. The information is also used to inform the driver of the optimal speed. The actual position is transmitted by radio to the bus company so they are always informed there the busses are. Some bus stops are equipped with displays showing the arrivel time if the bus is late.
Have you ever used your GPSr inside of a bus? In most busses the reception is poor, sometimes impossible but the newer ones have a plastic roof which provides almost perfect GPS reception, even of satellites in the zenith.