Accident Reconstruction

Jim Casassa | Bill Dickinson | Stuart Nightenhelser | James Sobek


Accident Reconstruction is a general term used to describe a process of analyzing an “accident” and using science to answer questions as to how it occurred.  Many people use the term synonymously with motor vehicle crash reconstruction, but these cases can range from a car crash to fire investigations, an industrial accident to a scaffolding collapse on a construction site.  Wolf has investigated collisions where brakes, steering, suspension, tires, and throttle systems were causative factors in a collision.
To arrive at the result we use the scientific method. We gather evidence from the incident site, the equipment, and utilize witness statements and other information gathered from the event.  We then apply principles of engineering, math and physics to develop an understanding and analyze the case. This allows us to determine what led to the incident within a degree of scientific certainty.  These methods are reproducible and consistent with industry practice.


Our crash reconstructionists are current with the ever changing technology associated with analysis of vehicle crashes.  We utilize scientifically based equipment to capture the collision scene and record evidence that may be later utilized in the case.  Our scenes may be recorded with a Sokkia total station to produce a scale diagram or even a 3-dimensional model to capture the scene the way it was on the day of the incident.
We have the specific equipment to document the vehicles involved in the collision and download the on board data recorders that are in many vehicles today.  This data may then be fed into state of the art programs such as HVE to analyze and reconstruct the collision.
When it comes to presentation, Wolf Technical Service leads the industry.  Our consultants effectively communicate scientific findings, and it shows in the courtroom.  Although trial and deposition testimony make up a very small percentage of our work, we have the ability to present difficult concepts using demonstrative evidence in order to educate our audience, allowing them to understand the incident.

There are multiple ways that a scene can be documented.  In a majority of cases it is most productive to perform a site survey.  A total station allows us to document the scene in a three dimensional world.  The total station presents us with information regarding roadway dimensions, inclines or declines of the roadway that may affect visibility, and also allows us to record evidence such as tire marks, gouge marks, debris, etc. and directly place them on the roadway. 

After performing a site survey, by using the information obtained we can then create a scale drawing of the collision scene and ultimately create a full computer graphic simulating how the collision occurred based on the available evidence and by using the laws of physics.  In addition to performing a site survey, we also take detailed photographs at the collision site.  These pictures include approach shots from each vehicle involved, detailed photographs of any available evidence, and any other information that we determine is pertinent.


There are many useful facts and measurements that can be acquired during a vehicle examination.   During a vehicle exam general information about the vehicle is noted.  This information includes, but is not limited to: VIN number, year, make model, curb weight, gross vehicle weight, brake type, airbag status, SDM availability, tire pressures, tread depth, tire size etc.  

An exanm also includes a set of 360 degree photos, as well as close ups of the damaged areas for documentation.
In the event of significant impact, crush measurements can also be beneficial to the reconstruction.  There is a certain amount of energy associated with crush.  By measuring the amount of deformation on a vehicle we can determine the change in velocity experienced by the vehicle due to impact.  
If there is a discrepancy about the status of a lamp (s) on the vehicle, a lamp exam, in some cases, will help resolve this issue.  A lamp exam can typically determine whether a lamp was on or off during a collision. For example the picture shown to the right represents a head lamp that was on at the time of impact.  This is determined from the stretching and elongation of the filament.



Jim Casassa
| Bill Dickinson | Stuart Nightenhelser | James Sobek