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Accident reconstruction typically requires estimating the change of velocity (Delta-V) imparted to vehicles during collision. Estimating Delta-V commonly involves measuring or estimating the deformation of the vehicles involved in a collision. Material coefficients, which relate barrier equivalent velocity (BEV) to deformation for the two vehicles, are then interpolated or extrapolated from barrier crash test data. Finally, the Delta-V for each of the two vehicles is usually calculated using single-degree-of-freedom (SDOF) impact mechanics formulas. This paper presents a derivation of SDOF impact mechanics formulas applicable to one-dimensional vehicle collisions. The governing equations presented are new, more complete and more efficient than previously published efforts. In particular, Newton's third law of physics concerning collision force is proportionally expressed as the product of vehicle weight, crush progression behavior and BEV.

Accident reconstruction experts are often asked to evaluate the visibility and conspicuity of objects in the roadway. It is common for objects placed in or along the roadway, vehicles, and required by Federal Motor Vehicle Safety Standard (FMVSS) No. 108 for certain vehicles and trailers, to have red and white DOT-C2 retroreflective tape installed on several locations. Retroreflective tape is designed to reflect light back towards the light source at the same entrance angle. The authors' literature review revealed that there have been no publications quantifying the performance of commercially available DOT-C2 retroreflective tape with real world vehicles. Therefore, without additional study, an accident reconstruction expert cannot know exactly how a specific type of compliant tape would perform beyond the minimum federal requirements. In the current research, the performance of white and red DOT-C2 retroreflective tape is quantified.

Vehicle change in velocity is recognized as one of the most influential parameters on occupant kinematics and injury potential in motor vehicle collisions. Basic engineering principals and some recent epidemiological research indicate the characteristics of the vehicle velocity change, such as the shape and duration of the acceleration vs. time pulse, may also be important. Automotive bumper designs could be enhanced by recognizing these characteristics to potentially influence occupant kinematics and Whiplash Associated Disorders (WAD) in low speed rear impacts. Low speed rear impacts were conducted with a Delta V of 11 km/h using the BioRID P3 anthropomorphic test device. Nominal pulse durations of 80, 100, 140 and 180 msec were tested by varying the dimensions of a foam interface between the impacting pendulum and the rear surface of the test vehicle.

Interest in the mitigation of whiplash associated disorders (WAD) has increased in priority over the last 10 years, and an increasing number of human subject rear-end collision tests have been conducted to assist in the understanding of WAD. Traditionally this testing has examined the effects of variations in occupant characteristics (age, height, gender, etc.), seat characteristics (geometrical and constitutive), and impact severity. This data has resulted in advancements in the understanding of WAD and has provided occupant performance corridors at specific velocity changes, however no controlled study has examined the singular effect of incremental velocity change increases on occupant kinematics. Moreover, while vehicle velocity change is typically employed as a singular measure of impact severity, it is of interest to examine whether this or other impact-related parameters, such as energy or acceleration, are also correlated with occupant kinematics.

In accident reconstruction, parameters such as the struck vehicle change in speed and the closing speed can usually be determined by means of conservation of energy and conservation of momentum approaches. While others have considered limiting cases of the effects of mass and stiffness on vehicle speed change and closing speed calculations, the full spectrum of variations in vehicle stiffness and mass ratios have not been rigorously evaluated. This paper presents a discussion of the effects on the calculated vehicle speed change as a function of the variation of the mass and stiffness ratios. Closed form analytical solutions and graphical representations are derived and depicted for the situations in which the ratio of the barrier impact test masses equate to that of the ratio of the vehicle masses for the reconstructed situation in question and for the scenario in which they do not.