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About 8,000 pedestrians are killed each year in the United States and probably another 180,000 are injured. This paper reports on an analysis of 1978 and 1979 New York pedestrian accidents to try to find any relationships between vehicle factors and pedestrian injury severity and location. In these data trucks and vans were found to be associated with more severe pedestrian injuries than passenger cars. However, within the passenger car category vehicle weight and injury severity were not clearly related. And few meaningful relationships were found between aspects of the passenger car front end configuration or the past production use of "soft" materials and pedestrian injury severity or location.

The current federal accident data collection system is inadequate. It does not produce representative data essential for answering cause-and-effect questions concerning accidents, injuries, and fatalities, and it does not produce adequate data essential for conducting cost-benefit analyses of changes in vehicle designs, highway designs, or driver licensing policies. A proposed federal data collection system (SIR) can solve those problems at a total cost of about $6 million a year. The SIR system would include 30 investigating teams precisely located throughout the U.S., and would include a Sampling program, an In-depth program, and a Rapid-response program. The sooner this system is established, the sooner government and industry will begin to obtain accurate and reliable answers to pressing questions in the field of highway safety.

Blunt abdominal trauma is a major cause of death in the United States. However, little experimental work has been done to clarify the mechanism of blunt abdominal injury and to quantify tolerance parameters for the abdominal organs. This paper describes a joint study by the Highway Safety Research Institute and the Section of General Surgery of The University of Michigan in which direct impacts were applied to livers and kidneys. The tests were performed in a high-speed testing machine at a controlled ram velocity and stroke limit. The organ was surgically mobilized in anesthesized Rhesus monkeys and then placed on a load cell while still being perfused in the living animal. Tests were performed at ram speeds of 120, 6000, and 12000 in/min (5, 250,and 500 cm/s). The resulting load-deflection data were normalized and average stress-strain curves plotted for each test. In addition, the resulting injury severity was estimated immediately after impact using an injury scale of 1 to 5.

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.

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 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.

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.

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.