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This paper reports on seventy additional tests conducted using a mechanical device described by Bonugli et al. [4]. The method utilized quasi-static loading of bumper systems and other vehicle components to measure their force-deflection properties. Corridors on the force-deflection plots, for various vehicle combinations, were determined in order to define the system stiffness of the combined vehicle components. Loading path and peak force measurements can then be used to evaluate the impact severity for low speed collisions in terms of delta-v and acceleration. The additional tests refine the stiffness corridors, previously published, which cover a wide range of vehicle types and impact configurations. The compression phase of a low speed collision can be modeled as a spring that is defined by the force-deflection corridors. This is followed by a linear rebound phase based on published restitution values [1,5].

Performing a reconstruction of sideswipe interactions is difficult due to the lack of permanent crush sustained by the vehicles involved. Previous studies have provided insight into the forces involved in creating various types of damage for vehicle-to-vehicle interactions during a sideswipe interaction. However, these data may not be applicable to the interaction that occurs when a tractor-trailer steer tire is involved. As demonstrated in previous studies, steer tire interaction produces a unique pattern of markings on the struck vehicle by the protruding lugs (wheel stud) of the steer tire. These studies have demonstrated that the pattern of cycloidal marks created by the wheel lugs can be used to calculate the relative speeds of the vehicles. While this is helpful in understanding the relative motion of the vehicles, it does not provide information regarding the forces applied at the point of contact.