KBatzler said:
 In CA, every collision with damage over $350 (I think,
unless it's changed) requires a police report.

To which David responded:
I wonder how you are supposed to know that at the time the
collision occurs! I would check your state drivers manual,
that sounds weird to me.

I used to have a pal years ago who was a policeman.  Though
it was another state, the same sort of dollar damage
reporting rule applied to on-the-spot accident reporting
before moving vehicles.  Since ordinary citizens aren't well
equipped to make such dollar damage estimates, that law
placed an unreasonable demand on people who were already
victims of another unhappy circumstance, - the darned
accident.  So I asked my friend Don about this.  He just
laughed and said it's another case where "we've got you" and
explained that if someone is being a "jerk" it gives police
one more thing to charge against you if they want.  I found
that to be a disquieting message.  I still miss him now,
though it's been years since he crashed his plane which
killed him.   Anyway, that's what one damned good cop had to
say about it.
John