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In this study, tests were performed with modified tires at the right rear location on a solid rear axle sport utility vehicle to compare the vehicle inputs from both: (1) tire tread belt detachments staged by circumferentially cut tires, and (2) a tire tread detachment staged by distressing a tire in a laboratory environment. The forces and moments that transfer through the road wheel were measured at the right and left rear wheel locations using wheel force transducers; displacements were measured between the rear axle and the frame at the shock absorber mounting locations, ride height displacements were measured at the four corners of the vehicle, and accelerations were measured on the rear axle. Onboard vehicle accelerations and velocities were measured as well. The data shows that the tire tread belt detachments prepared by circumferentially cut tires and distressed tires have similar inputs to the vehicle.

In this study, tests were performed to understand the effects of asymmetric longitudinal forces on vehicle response which may be created in certain staged partial tire tread belt detachment tests. In a very small number of tests performed by others, tires cut to simulate partial tire tread belt detachments created longitudinal drag forces at the separating tire that induced substantial vehicle yaw. This drag force and yaw response are independent of vehicle type and suspension type; they are created by the separating tire tread interacting with the road surface and / or vehicle. Similar yaw inducing drag forces are further demonstrated by applying braking to only the right rear wheel location of an instrumented test vehicle. It is shown that vehicle yaw response results from this longitudinal force as opposed to vertical axle motion.

In this study, tests were performed with modified tires at the right rear location on a solid axle sport utility vehicle to compare vehicle inputs and responses from both: (1) staged tire tread belt detachments, and (2) stepped diameter (“lumpy”) tires. Lumpy tires consist of equal size sections of tread that are vulcanized at equidistant locations around the outer circumference of the tire casing. Some have used lumpy tires in attempt to model the force and displacement inputs created by a tire tread belt separation. Four configurations were evaluated for the lumpy tires: 1-Lump, 2-Lump (2 lengths), and 3-Lump.

Representative vehicle inertial characteristics are important parameters for the development of motor vehicles and the proper operation of on-board systems. The Vehicle Inertia Measurement Facility (VIMF) measures vehicle center of gravity location, principal moments of inertia, and the roll/yaw product of inertia. It is important to understand the VIMF’s accuracy and repeatability, as well as the underlying methodology and assumptions, when performing tests or using the results of the test. This study reports on a repeatability analysis performed at the lower and upper limits of the VIMF. Each test performed is a complete drive-on/drive-off test. The test sequence involves the repeatability evaluation of several different machine configurations. Ten complete tests are performed for each vehicle. To better address the possibility of measurement bias, the design and verification of a calibration fixture for inertial characteristics is presented.

The documented availability of electronic stability control (ESC) systems on passenger vehicles is useful in understanding the integration of ESC technology into the North American automobile market. Unfortunately, the sources that document ESC system availability are not always consistent with each other and many show discrepancies with information from the manufacturers. In this study, the history of the implementation of ESC systems in passenger vehicles is reported based on information combined from several different organizations including the National Highway Traffic Safety Administration (NHTSA), the Insurance Institute for Highway Safety (IIHS), Ward's Auto World, and Consumers Reports. Where discrepancies exist between these different sources of data, clarification was gained through further research of information available from the manufacturer, including corporate press releases, owner manuals, and vehicle brochures.

In crash analyses, components or component assemblies are evaluated to identify if they were damaged as a result of the crash or if they lost function prior to the crash. Determining the circumstances that cause a component to become disabled can be useful when evaluating the cause of a crash. This study focuses on spherical ball joints commonly used in automotive suspension systems. Analyses can include the evaluation of the ball joint itself, the surrounding components, evidence at the scene, and the circumstances of the specific crash. In this study, the causes and conditions for a ball joint separation are analyzed, in part, through both component level testing and full vehicle testing. Laboratory tests were performed on upper ball joint assemblies where loads were applied in multiple directions and the residual damage to the components was measured and documented.