Are you liable for another person's car if they refused to call the police to the scene and left and you didn't know you had to make a report?
==Complex question== There are a lot of unknowns in your
question. One is left to wonder why you wouldn't eagerly call the
police and/or file a report yourself after the other party (call
him Party B) fled the scene, whether you were required to or not.
One can only assume that there was little or no damage to your
vehicle. We can also assume that the configuration of the accident
was not favorable to Party B, which is why he was in a hurry to
scram. (Or perhaps he wasn't where he was supposed to be at the
time of the fender-bender and didn't want an official police report
to document his location.) Whatever the case, if there was visible
damage to Party B's vehicle, then you should have been concerned
about potential reports and claims -- false or accurate -- he could
make against you. But to try to answer your question, you may still
be liable for the damage you caused to Party B's vehicle, but his
fleeing the scene may mitigate substantially his claim against you
because, by leaving, he assumed the risk of something happening to
his car -- and intervening event that would break the
proximate-causation chain. Further, leaving the scene of an
accident with visible damage is a criminal act in some states and
is, per se, negligent, which may also militate against him.