What are some common causes of bus accidents?

Bus accidents may be the result of driver inattention or distraction, driver fatigue, speeding and/or dangerous driving, sudden stops or swerves to avoid hazards, influence of alcohol or drugs, poor road conditions, vehicle disrepair/malfunction, hazards on the bus (slippery floors, uneven flooring, falling objects, doors closing prematurely), physical contact (intentional or unintentional with other passengers), verbal abuse or harassment by passengers or the driver.