How incredibly refreshing to find an accident reconstruction forum based in scientific research and repeatable empirical testing rather than rule-of-thumb calculations and urban legend! I only wish that there were more like-minded folks posting to this forum because it seems that other accident investigators and engineers are gravitating to the websites presented by ex-police officers. That is a shame because it means that the same old myths will be perpetuated and we will not see improvements to what is considered accident investigation by the judicial community unless we drag it kicking and screaming. Since the police have a leg up on the scientists in the legal forum, it won't come easy. Tragically, real people with real lives are profoundly changed forever because of some unqualified opinion or poorly paraphrased statement recorded in a police report.
Anyway, kudos for the forum! I'll be checking back from time to time because I seem to have a tough go at making "friends" on the police sites (hehe).
PS I have nothing against police officers, per se. My dad is one, and my family has quite a few of them in it. Perhaps I'm jaded, but I just don't think they are particularly trained very well in accident reconstruction but are given boatloads of credibility in court for having conducted poorly-documented and hastily-reconstructed investigations for a couple of years before entering private practice.
That ought to spark some discussion!
David, I am not sure why so few posts. I have good friends who were with the highway patrol and switched to experting. They generally are not trained in engineering concepts, and consequently are not familiar with the proper formulation of a reconstruction problem.
Problem areas are: Noncommon Crashes that do not fit the mold; limitations on standard linear momentum; velocity/time diagram to solve two-vehicle relative motion; braking efficiency of commercial trucks; the use of linear/rotational momentum; plus others.
Often their solution is to take an average of something. They are intimidated by physics. As Joe Badger used to say: Reconstruction is like throwing a hand granade, closeness counts. When the accurate answer is 63 mph, and they get 67.35 mph, however using wrong physics, the judge will let it in, unless the other expert does his homework educating "his" lawyer for reveaaling cross examination.
Take care, Rudy Limpert
That is so very true. At one time I had great respect for the CHP's Multidisciplinary Accident Investigation Team (MAIT) division and I thought they did really good work that was exhaustively thorough. They would look at accidents in such detail that they would include reports from nearby NOAA weather stations, 48-hour driver profiles, accurate physical evidence measurements, and the correct (in method and computation) calculations for the subject accident. Unfortunately, it seems that the turnover rate for police officers has taken its toll on the MAIT division. I think that they had some really good people (perhaps an engineer or two?) that set the program up, then retired or got promoted or something like that.
I have been trying to get support for the idea that local agencies consider hiring professional surveyors to document accident scenes. I think they ought to contract some of their more important accident investigations to civilian companies that have the expertise, interest, and experience necessary to fully investigate a crash. It would be much cheaper than training their own people to do it, the field work could be signed by a licensed surveyor or engineer, the data would be reliable, and it would not keep officers tied up recording measurements when they could be out chasing bad guys.
Sadly, it appears to be an exclusive club that only badge-carrying members need apply. It's not that I really want the job, because I don't. I am just getting tired of the poor quality accident reports that seem to continuously land on my desk. I mostly feel incredible empathy for the victims of a car accident (and their families) and I think they deserve much better from their sworn police officers. In my opinion, if the police are going to make it an exclusive club then they better **** well be thorough and accurate. Just my opinion, but it seems pretty reasonable to me.
P.S. You would not believe the kind of flak I get for suggesting such blasphemous ideas at IPTM courses!