Posts Tagged ‘scale diagram’

The Value of Demonstrative Evidence

Thursday, September 3rd, 2009

Quality Photographs

As the saying goes, a picture is worth a thousand words. Well a picture serving as demonstrative evidence is equally powerful. It enables the investigator to document all aspects of the scene, vehicles, and any other valuable evidence for future reference and analysis. Additionally it enables others such as claims adjusters, lawyers, other investigators, juries, and judges to examine the scene, vehicles, or other evidence for themselves.

In regard to this last point, it must be emphasized that the photographer needs to be knowledgable about how to take accurate photographs that are true representations of the evidence. Care must be taken in the use of special lenses or filters that may distort the perspective or appearance of the shot. However, as long as proper equipment and techniques are used, a photograph generally tends to be considered irrefutable evidence.

Scale Diagrams

A scale diagram is another useful piece of demonstrative evidence. Assuming it is based on accurate measurements of the scene and vehicles, it can be used to very accurately depict locations and speeds of vehicles at different times as the vehicles approach and depart from the area of impact. Also line of sight or other important characteristics of the particular accident can be represented graphically to enhance understanding. These diagrams are helpful to the reconstructionist for doing analysis and calculations. They are useful to other interested parties to be able to visualize how the accident occurred and to understand the reconstructionists conclusions.

Animations and Simulations

Finally we will look at animations and simulations. Due to the advances in computer technology we are now able to generate these pieces of demonstrative evidence that are arguably the most advanced and self explanatory available. Although it may be self-evident we will define the difference between an animation and simulation. Both are videos generated from a series of either two-dimenisional or three-dimensional shots that show the vehicles moving through space and the accident sequence. However, the movement of an animation is completely directed by the animator whereas the movement of a simulation is generated by a computer program designed to replicate how a vehicle would move, react, and deform in an accident scenario in the real world. This algorithm is of course then based on general principles of engineering and physics. The animation allows the reconstructionist to put together his entire analysis, calculations, and measurements into one package and via this video show how the accident occurred. Simulations, assuming the algorithm is sound and propertly applied, are useful for testing theories and analysis. Click below for an example of each:

Animation

Simulation

Jonathan McGehee