Many people think that the collision report is dispositive on all issues related to a wreck.

That's understandable. It's an official government document. And it's frequently made after law-enforcement speaks with both participants and witnesses.

Also, there's an assumption – sometimes accurate and sometimes inaccurate - that the law-enforcement officer involved has training in accident reconstruction.

However, there's a statute in Washington, RCW 46.52.080, that says: "No such accident report or copy thereof shall be used as evidence in any trial, civil or criminal, arising out of an accident...."

Receiving a citation for a traffic infraction, paying the fine, or a finding of “infraction committed” are not evidence that the cited party caused the collision. Billington, v. Schall, 42 Wn.2d 878, 259 P.2d 634 (1953).

(This rule exists because, in lots of situations, it's more efficient for people to pay small fines, than it is to actually contest a citation.)

In the vast majority of cases, liability (if not admitted) needs to be established through witnesses to the collision and accident reconstructionists hired by the parties.