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A study has been conducted as an initial step in determining the differences observed between the motions of a living human impact sled test subject and a dummy test subject. The mechanism which is proposed for accomplishing this is the HSRI Two-Dimensional Mathematical Crash Victim Simulator. A series of measurements were taken on human test subjects, including classical and nonclassical anthropometric measurements, range of motion measurements for the joints, and maximum foot force measurements. A series of mathematical expressions has been used to predict body segment weight, centers of gravity, and moments of inertia using the results of the various body measurements. It was then possible to prepare a data set for use with the mathematical model.

Advanced crash-impact protective equipment and techniques which have application to crew and passenger crash safety in jet transport aircraft have been evaluated. Thirty-two state-of-the-art concepts have been analyzed from a systems engineering viewpoint with respect to several engineering, psychological, and medical disciplines. In order to provide a framework to determine the function level of each concept, an event-oriented flow chart of the crash and escape event has been prepared. The 17 events occurring during a crash are included, beginning with system installation and concluding with emergency evacuation of a disabled aircraft. Performance with respect to the events on the flow chart are rated in terms of hazards of system use, maintainability, reliability, human factors, and other technological considerations.

The effectiveness of restraint systems in preventing fatalities or reducing injury has been estimated by extrapolation of data from several sources: (1) Sled tests with dummies (2) Analysis of accident case studies (3) Statistical comparison of belted and unbelted persons in crashed cars. (4) Before and after studies (e.g., with respect to belt-usage legislation, or as with the 1974 starter-interlock program) Fatality reduction estimated by the case study method is on the order of 30 percent, but by the statistical comparison method at 50 percent or sometimes as high as 60 percent. Other differences (e.g., driving habits) between belted and unbelted persons explain the disagreement between the two estimates. More complete analysis of available accident data suggests that the higher values were obtained without correction for such factors as crash severity or occupant age.

The literature on headlamp aiming is surveyed in detail to pinpoint the various sources and magnitudes of aim variance. Four major sources of variance are identified (differences between beam and mounting plane, photometric changes in use, long axis alignment, and human factors), along with a number of others of lesser consequence. Illustrations are offered showing the expected population variance under a variety of conditions. It is apparent that, at the present state-of-the-art, a substantial percentage of the lamp population can be expected to be beyond the limits recommended in SAE J599c. It is further apparent that this would be true regardless of whether or not a vehicle inspection program is in operation. Recommendations are given regarding research emphasis in headlighting. Ways of reducing variance from the most significant sources are considered and recommendations offered.

This paper reports the results of a study which had as its aim the determination of braking performance currently achievable by buses, trucks, and tractor-trailers, and the improvement of this performance by use of advanced braking systems. Both vehicle testing and analytical techniques, including dynamic modeling and simulation, were used in the program. Performance qualities essential to braking systems are enumerated, which, when given quantitative definition in the light of performance achievable, can form the basis of rational performance requirements for commercial vehicles.

Mechanical properties have been obtained from a recent series of truck tire tests using the Highway Safety Research Institute's (HSRI) flat bed tire testing machine. In addition to the vertical and lateral spring rates, a set of three parameters characterizing traction properties of the rolling tire are defined and measured. The influence of tire load and inflation pressure on mechanical properties is found to be significant. Carpet plots of lateral force versus tire operating variables such as camber and slip angle are used to illustrate the effect of changes in ply rating, tread pattern, and wear. Corresponding variations in the mechanical properties are noted. The results of an experiment to determine the relationship between single tire and dual tire force and moment producing capabilities are also described.

This paper describes an injury criteria model implemented in computer language, and a restraint system effectiveness index for evaluating the degree to which the vehicle environment can prevent or reduce occupant injuries. The need for criteria of this type is based on the fact that if the degree of protection offered to a vehicle occupant by a restraint system or a vehicle interior (a function of the distribution and magnitude of the forces transmitted to the occupant) could be expressed in quantitative terms, then, more meaningful comparisons could be made between restraint configurations, and, areas of needed biomechanical research and statistical accident investigations could be more readily identified on the basis of the sensitivity of the results when the injury or effectiveness criteria are applied. The injury criteria model consists of three parts: 1.

Mathematical models of the human body subjected to an impact environment have been developed by many research groups in industry, government, private research organizations, and universities. In most cases, the models have not been verified by or compared with experimental results. The purpose of this paper is to show comparisons between the two- and three-dimensional crash victim simulators, which have been developed at the Highway Safety Research Institute of The University of Michigan, and front and side impact sled test results using anthropometric dummies.

An engineering analysis of vehicle braking is presented in terms of the utilization of available road friction. Physical relations are derived which allow the determination of optimum brake force distribution on front and rear wheels as a function of axle loading. Ideal braking distribution curves are shown for a typical vehicle in the loaded and unloaded conditions. A technique is suggested for rational design of braking system parameters. It is applied to the case of a two-stage proportioning system, and is validated by experimental data from tests using a specially equipped light truck. It is concluded that a proper design analysis can establish a combination of braking system parameters which results in improved utilization of available friction. A simple, self-adjusting brake proportioning system can be a highly cost-effective safety device for truck use.

An open-loop limit-maneuver test methodology was refined from an earlier study which hypothesized a relationship between vehicle performance and highway safety. Refinements in methodology were attained in the areas of test apparatus, test procedure, data processing, and performance interpretation. Open-loop response measurements were conducted on a representative sample of 12 contemporary passenger vehicles. Numeric characterizations of performance are presented, indicating the range and distribution of response properties exhibited by the vehicle sample.

This paper reviews the state of theoretical and experimental technology relative to the dynamic performance of articulated highway vehicles. The review contains three major sections, corresponding to the traditional breakdown of vehicle performance: directional performance, braking performance, and combined directional and braking performance. An attempt is made to take a frankly evaluative point of view and to point out knowledge gaps and unanswered questions, in addition to documenting previous accomplishments and progress. The paper concludes with some recommendations for future research consistent with the findings of the review.

This study Investigates the response of human cadavers1, and live anesthetized and post-mortem primates and canines2, to blunt lateral thoraco-abdominal impact. There were 12 primates: 5 post-mortem and 7 live anesthetized; 10 canines; 1 post-mortem and 9 live anesthetized; and 3 human cadavers. A 10 kg free-flying mass was used to administer the impact in the right to left direction. To produce the varying degrees of injury, factors including velocity, padding of the impactor surface, location of impact site, and impactor excursion were adjusted. The injuries were evaluated by gross autopsy, and in the case of live subjects, current clinical methods such as sequential peritoneal lavage and biochemical assays were also employed. Mechanical measurements included force time history, intraortic pressure, and high-speed cineradiography to define gross organ motion.

During recent years, the Highway Safety Research Institute (HSRI) has developed and validated two- and three-dimensional models describing the motions and forces acting upon an occupant during a collision. These inexpensive-to-operate models are performing with approximately 90% accuracy in parametric studies of classical crash configurations. In our own validation procedures, contacts with automobile development and design groups, and discussions with federal agencies, certain shortcomings of mathematical modeling procedures have been isolated. These include primarily the inability of the user to determine and input data to the computer programs and also to specify force, motion, velocity, and acceleration output data in a form applicable to the various vehicle design, human tolerance, and compliance tasks for which the models have been developed.