Busses present unique dangers, both for passengers and those who are in collisions with them. From the passenger's perspective, you might not think they are at risk of injury in a crash because a bus is much larger than a car.
However, bus engineering does not always take passenger safety in mind. Passengers do not have seatbelts, and some may stand on a crowded bus. One unpredictable movement or momentary jarring impact can cause a passenger to lose their footing and fall.
The most common bus accident injuries for passengers are neck and back injuries. The sudden movement can cause passengers to fall or move unnaturally. Even a "minor" bus accident can cause lasting neck and back injuries requiring surgery and rehabilitation.