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Tire-roadway frictional drag, an important consideration for transportation accident reconstruction, is dependant on vehicle, roadway and environmental factors. Vehicle factors include vehicle specific properties such as geometry and inertial parameters, braking system type, tire size, and tire properties. Roadway factors include grade, pavement type, construction, pavement age, and other parameters. Environmental factors include temperature and inclement weather. In order to control these (and other) vehicle, roadway, and environmental factors, the determination of tire-roadway frictional drag is done through staged testing using an instrumented vehicle. Staged testing is typically performed with an exemplar vehicle on a similar roadway under comparable environmental conditions. Engineering instrumentation includes acceleration and velocity sensors as well as a brake gun to directly measure total braking distance.

With ABS-equipped motorcycles becoming more pervasive, it is critical for collision reconstructionists to have a firm understanding of what evidence may be generated during aggressive braking events performed with these braking systems. To develop a better understanding, thirty-one instrumented braking tests were performed and are reported in this study. Three different surfaces using three current ABS-equipped motorcycles were used to study the residual visible roadway and tire evidence resulting from hard braking events involving front-only, rear-only, and maximum effort braking maneuvers. Data from these tests were analyzed to determine the resultant deceleration, which serves to add updated data to the current body of knowledge. The majority of braking tests did not generate visible roadway evidence. Specifically, conventional public roadway surfaces exhibited no evidence of braking until the motorcycles reached very low speeds.

Vehicle to vehicle sideswipe collisions may involve contact between a vehicle body and a contacting vehicle's rotating wheels, tires and lug nuts. During a sideswipe collision between a truck and an automobile it is not uncommon to see lug marks in the shape of consecutive damage loops or strikes on the side of the impacted vehicle. The damage loops or strikes are generated by the protruding lug nuts of the truck wheel as it passes by the impacted vehicle at a shallow angle. Additionally, rubber transfers due to contact with the tire sidewall and metal scraping from the wheel rim also leave distinctive shapes on the sides of the contacted vehicle body. The tire, rim, lug nut markings and associated damage manifest themselves as a special case of the epitrochoid and can be geometrically and mathematically described. Presented is a derivation of the equations that govern the lug, rim and tire positions and relative motions.