Technical Crash Investigation Resources


Sometime around the mid to late 1980's, two deputies with the Portage County Sheriff's Office noticed a need for seeking more advanced training in the field of post-crash technical accident investigation and reconstruction. In the years that followed, these individual deputies were able to receive training and attend various technical conferences and seminars and network with instructors and other law enforcement personnel involved in crash reconstruction.

During the formative years, the two primary technical investigators had only the basic tools at their disposal. An investigative kit was a pretty basic assortment of marking paints, lumber crayons, note taking material, traffic templates, PK nails, and an assortment of various tape measures from 25 ft to 300 ft in length.

Scene surveys often took several hours when tape measures had to be strung either along the edge of a roadway for a baseline to take other measurement data from, or from reference points to triangulate measurements and extensive note-taking was necessary. After measurement data was recorded, a scale diagram was created using an architect's ruler and a traffic template. Supplemental reports based on the investigation and other pertinent data would be compiled to accompany the State of Wisconsin accident report.

In the mid-90's, two more deputies were added and began the progression of training which normally consists of At-Scene, Technical Crash Investigation, Vehicle Dynamics, and Crash Reconstruction. Each one of those instruction units is usually 40 to 80 hours long and many more courses exist for specialty disciplines involving all aspects of the science of crash reconstruction.

Also during this time, the Portage County Sheriff's Office made a purchase of a Nikon D50 total station. This instrument is very similar to what a surveyor uses for mapping distances, elevations, and angles. The total station interfaced with a small computer and after surveying a scene the data would be downloaded into a computer aided drawing program. Because the data included changes in elevations, more accurate calculations could be done using this measurement system.

The science of technical crash investigation is ever-changing as is technology. Changes in vehicles, restraint systems, and on-board data recorders brought about new and different investigative techniques and resources. Changes in computer technology, operating systems, and data acquisition also changed.

Sometimes information sought from a crash investigation has been beyond the resources of our agency, and we have benefited from assistance we have received from the Wisconsin State Patrol Technical Reconstruction Unit. Troopers assigned to the TRU are continually working case loads dedicated to complex traffic crashes, and they also receive the most training and experience in the science of crash reconstruction. When needed they have assisted our agency with diagnostic downloads of on-board data recorders, vehicle inspections, and reconstruction assistance.

Because of this cooperation and a desire to have interoperability, we made an upgrade to our data collection resources. In early 2009, our agency purchased a replacement to our original total station and purchased a Trimble 5603 total station with Autolock. This total station was purchased because the WSP TRU and the WisDOT all use this same operating system. All codes came pre-loaded based on the WSP preferences, and this allows any number of trained operators to assist our deputies with familiarity of the operating system. Also, if our total station data is downloaded into a different computer by a different investigator using the same CrashZone software we use, the transferred data will all look the same on a diagram. This is important when other investigators may be assisting on case.

The Autolock function of the new total station interacts with a 360 degree prism pole and the "gun" of the total station actually follows the "rod man" throughout the scene. The operator at the data collector needs only to hit an enter key and change code names and numbers when directed. The system is the next best thing to using a totally robotic one-man total station. The system can also be used in a reflector-less mode for taking a variety of shot data which would even allow for the creation of 3D diagrams, if needed.

Data collection at scene with the newest total station is night and day different from the old unit. The Trimble unit will collect data almost as fast as you can walk through a scene. This allows for quick clearance of roadway crime scenes and takes deputies away from the harm of working near moving traffic sooner.

To more accurately collect roadway data and friction values, we also added a Vericom VC3000 brake meter to our equipment inventory. This device allows investigators to collect the most accurate drag factor data to use in speed calculations.

Currently, four deputies with various levels of training within the discipline of technical crash investigation work on the more complex and serious crashes that occur in our county. Deputies within the department that are interested in furthering training within this field are always encouraged to demonstrate their interest and seek training within this discipline.