Forensic Testing Services

FOOTWEAR AND TIRETRACK EXAMINATION

The examination of impression evidence is usually accomplished via a visual comparison of the characteristics in a photographed impression and test impressions made by the known shoe or tire. The first part of the comparison involves the class characteristics of the shoe or tire including the physical shape and size as well as the design or pattern on the bottom of the shoe or tire, which leaves its print in the impression. The second point of comparison is the wear characteristics present in the impression. For example, the heel of a shoe may begin to wear on the edge. This, and other wear, would change the pattern of the shoe. The third point of comparison is of accidental characteristics, such as a cut mark in the known shoe or tire. These cut marks or damages to the pattern of the shoe or tire make a shoe or tire unique and can possibly enable the positive identification to an impression at a crime scene.

Even without a definitive tire impression, measurement of the tire track and wheelbase of an unknown vehicle can lead to identification of make, model, and year of a vehicle by utilizing forensic databases. The manufacturer and model of a shoe may also be able to be determined from questioned impressions.