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Driver visibility from commercial vehicles is often an issue in post-accident litigation. While the visibility through the windows of most vehicles is restricted due to the required structure of the vehicle itself, most manufacturers and users incorporate a series of mirrors to enhance driver visibility and to reduce blind spots. The challenge for an engineer is to first demonstrate what the driver could see to a reasonable degree of engineering certainty, and then to convey this information in a form that is easy for the lay person to grasp. This paper outlines procedures for calculating and modeling the driver visibility from commercial vehicles. The primary techniques presented require access to the vehicle, although the paper also presents techniques by which visibility can be analyzed through photogrammetry and 3-D computer models, both for the vehicle and for any mirrors incorporated onto the vehicle.

In reconstructing any accident, the reconstructionist must properly account for uncertainty in their analysis. One popular method of examining and quantifying the uncertainty within an analysis is the use of Monte Carlo simulation techniques. The methods have been well established and published over the last several years by numerous authors. One of the key factors underlying the Monte Carlo analysis is the assumed probability distribution of the individual factors within the analysis. The literature has examples and recommendations for assuming normal, uniform, or custom distributions for input parameters. However, the literature to date has not examined how the assumption of a distribution affects the resulting probability distribution of the Monte Carlo analysis. This paper attempts to address this issue.

This paper clarifies the relationship between the absorbed crush energy and the dissipated crush energy and explores the use of each in crush and conservation of energy analysis. There is inconsistency and confusion in the literature of accident reconstruction regarding when crush analysis and conservation of energy analysis should use the absorbed crush energy and when it should use the dissipated crush energy. It is demonstrated in this paper that crush analysis calls for the absorbed energy, while conservation of energy analysis calls for the dissipated energy. However, this paper also shows that the equations of crush analysis and conservation of energy analysis can be written in terms of either the absorbed or the dissipated crush energies, since the absorbed and dissipated energies are related through the coefficient of restitution (when friction-type energy losses are assumed negligible). The assumptions of crush analysis are explored in order to develop a consistent approach.

This paper examines the validity of the effective mass concept used in the CRASH 3 damage analysis equations. In this study, the effective mass concept is described, the simplifying assumptions that it entails are detailed, and the accuracy of the concept is tested by comparing ΔVs calculated from the CRASH 3 equations to results of numerical simulations with a non-central impact model. This non-central impact model allowed the effective mass concept to be tested in isolation from other assumptions of the CRASH 3 program. The results of this research have shown that the effective mass concept accurately models the effects of collision force offset when certain conditions are met. These conditions are discussed, along with their implications for damage interpretation. This paper also presents an analytic expression that relates damage energy to closing speed (initial relative velocity) for the general case of non-central collisions.

Current windshield manufacturing processes produce residual tensile stresses near the edges of windshields. This residual tensile stress reduces the ability of the windshield to withstand suddenly applied external loading over a short time interval near the edge. Present manufacturing processes can reduce some of the residual tensile stress produced during the annealing process, but currently it is technically difficult to eliminate. However, an innovative and more cost-effective solution for the residual tensile stress problem has been proposed. Application of a thin film of polycarbonate around the perimeter of the windshield allows the energy generated during impact loading to be dissipated without the need to change the windshield's material properties.

This paper is the summary of the current state of the art in the multidisciplinary science of biomechanics as it relates to head injury. A review of typical occupant dynamics is presented, and injury causation mechanisms are examined. The history of methods used to measure impact severity and human tolerance levels to impact is reviewed and possible modifications of the Head Injury Criteria (HIC) are explored. Engineering analysis of individual cases is suggested to evaluate the response of the head and brain to impact. A bibliography of technical literature on head injury is included.