An accident can happen within a seconds. The following video shows 2 poor bus collapsed each other due to an idiot driver in front of first bus. The car driver suddenly stop when the lights turn to yellow and the driver bus behind it try not to hit the car but incoming bus on opposite lane hit the first bus.
Our advise, if you are a car driver, please see your back mirror before you stop. And if you are a bus driver, please do have a gap between you and your front car.