Accident:  
1. an unfortunate incident that happens unexpectedly and unintentionally, typically resulting in damage or injury: 
2. an event that happens by chance or that is without apparent or deliberate cause

This definition seems appropriate in this and in most cases I see in the newspaper.  You are either implying that car drivers are intentionally running into each other and others or that they are not 'responsible' for accidents.

Drivers remain 'responsible' even when the collision is due to negligence; you seem to be denying that.  

Police are taught not to use 'accident' in their reporting because that is a legal term which will be ultimately decided in a court type proceeding.   They are required to use objective language when at all possible.