In Preparing and Presenting Expert Testimony, traffic engineer and accident reconstruction expert witness Lawrence Levine writes:
Gathering of Information 4. The entire history of the location involved including, but not limited to, the road history, original plans, reconstruction plans, maintenance history and traffic control history. He or she must be familiar with the accident history. (Note: the expert must make his own determination regarding accidents based upon accident report data, not Federal-funded summaries and reports by others. That may be excluded as evidence by Federal law. Also, the courts will generally only accept as example/reference accidents which are similar to the one at issue during trial to substantiate an opinion. Although work done at a site or changes made AFTER an accident are normally not admissible, in some instances the information contained in post accident documents can be used to show a pre-existing condition.) Consult the attorney regarding any post accident repairs or work done and its effect on the case. The expert must know the relevant state and standards in effect or used at the time of each road history event, plan or construction document, and installation of a sign or other traffic control device.