I’ve blogged in the past about the importance of measuring in forensic engineering investigation. About getting on site and getting your hands dirty and mud on your boots. This is particularly true when an engineering failure or a personal injury accident involves the natural environment or the foundations, soils and water beneath the site – wet, messy, untidy places.
Everyone should do this – experts, civil litigation lawyers and claims consultants alike. Go and see and measure things.
I was reminded of this on Monday when I attended a workshop on Advanced Collision Reconstruction in Moncton – read on, your eyes won’t glaze over at what I tell you, and you may gain some insight into what’s important to experts.
The workshop was organized by the Canadian Association of Technical Accident Investigators and Reconstructionists (CATAIR) and presented by Advantage Forensics Inc, Toronto. The course instructor was Jason Young, B.E.Sc., M.A.Sc., P.Eng., a senior collision reconstructionist with Advantage. There was some emphasis in the course on simple measurement with tapes and rulers. Also considerable emphasis on the analytical technique used by Jason.
Police officers – present and former, professional engineers and others attended the workshop, people who reconstruct accidents. There’s a lot of very impressive expertise in this field in Atlantic Canada. We do have a lot of car accidents in the area. Also people like me attended who practice forensic engineering investigation. I have a good interest in the techniques used in fields of investigation related to my own.
The session topics were:
- Crush Energy Analysis
- Introduction to Collision Biomechanics
- Rollover Investigations
The topics might look heavy to non-technical people but they rely on simple measurements – first and foremost – and an analytical procedure and software.
We’ve all seen those pictures of horrible car crashes. Cars and trucks so mangled in some that you are hard pressed to see a vehicle in the mass of metal. In illustrating his lectures, Jason showed us a lot of pictures like this, also video of simulated field trials and tests. Head-on crashes, T-Bones, rear end crashes, roll-overs, and pole and tree impacts.
The speed of the cars and trucks in an accident is key information in learning why and how the accident happened – reconstructing it. No surprise there. Speed is obtained from analytical procedures – Jason briefed us on one he uses, and software that are fed a lot of simple measurements. But important measurements because garbage in garbage out.
Two basic measurements are a site survey - like in land surveying of old, and the crush depth.
The crush depth is a simple measure of the length and depth of the hole in the front, side or rear of a vehicle hit by another during an accident. These measurements give the “damage profile” in accident reconstruction. It’s not much different than measuring the length and depth of a trench excavated in your garden by a backhoe or yourself.
The site survey is just that – measuring and describing the location and height of the features that characterize the surface of the site. These would be the natural features in the terrain, the layout of the road, the position of the vehicles, the location of poles or trees that were hit, and the location of marks left on the ground by the crashing vehicles. We do this simple kind of survey of a house lot before we build on it.
Two measurements – crush depth and site survey, that quantify the mess of a car or truck accident. There’s more involved, of course - analytical procedures and software, also knowledgeable reconstructionists, but nothing happens until the measurements are taken.