Why are skid marks important?
Skid marks are important physical evidence gathered by investigators at collision scenes. For example: When brakes are applied to full wheel lock or impending wheel lock on anti-lock brake systems, during a hazard situation, tire friction marks may be left on the roadway surface. The length of these tire friction marks can often times be used to determine the estimated speed of the vehicle, at the time the tire friction mark was made. Two factors must be considered when estimating speed from tire friction marks: 1) The distance the vehicle slid and 2) The coefficient of friction (drag factor) of the roadway surface in question.
