Only in the most *unusual* circumstances. I've corresponded here in Usenet with one of the better police experts and I was stunned to find that he used a *standard* weighted 'drag block' to determine coefficient of friction on various surfaces. It had a rubber compound good for about 0.75G. His speed calculations would therefore be wildly incorrect for something carrying the kind of 'gumballs' I've run in the past.
You could *probably* find out just about anything you wanted to about the circumstances of a given crash - if you could afford it.
-- C.R. Krieger (Been there; didn't crash)