Yeah, saying 'accidents happen' is usually a bit of a cop out. There is always a cause. It's like saying the car lost control. No it didn't, the driver lost control of the car. An accident would be a tree falling onto the car while it was driving along. There are many reasons why crashes occur, and not many are truly accidental. Lack of attention, fatigue, driver inexperience, innappropriate driving for the conditions, poor vehicle condition, the list goes on.
Granted, the crash might not be one drivers fault, but it inevitably is another's fault. Cars don't just crash into each other for no reason.