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Results from a series of repeated-impact crash tests of a 1990 Ford Taurus sedan into a rigid, vertically offset barrier are presented in this paper. The purpose in conducting these crash tests was to further investigate override/underride crush energy behavior. The testing set-up and conduct are described and the test results, including impact speed, rebound speed and residual crush profiles are presented. The results of these tests are discussed and compared to the existing crash test data for this vehicle model. Previously suggested override/underride crush energy methodologies are also applied to the new data.

In automobile accident reconstruction it is often necessary to quantify the energy dissipated through plastic deformation of vehicle structures. For collisions involving the front structures of accident vehicles, data from Federal Motor Vehicle Safety Standard (FMVSS) 208 and New Car Assessment Program (NCAP) frontal barrier impact tests have been used to derive stiffness coefficients for use in crush energy calculations. These coefficients are commonly applied to the residual crush profile of the front bumper in real-world traffic accidents. This has been accepted as a reasonable approach, especially if there has been significant involvement of the front bumper and its supporting structures. For impacts where the structures above the bumper level are deformed more than the bumper itself, this approach may not be so readily applied.

In this paper a detailed analysis of a staged two-vehicle impact is conducted. The staged impact consisted of two moving vehicles impacting in a left front corner-to-right front corner configuration. Both vehicles were outfitted with an array of triaxial accelerometers. An Anthropomorphic Test Device (ATD) was located in the driver position in one of the test vehicles. High-speed film cameras were installed on the vehicle, documenting the test dummy motion during the impact. The impact and subsequent vehicle motions were documented with offboard real-time video and high-speed film cameras. The accelerometer data from both vehicles are analyzed. This analysis demonstrates the effects of yaw motion on the determination of Delta-V and on occupant kinematics. The notion of a Principal Direction of Force (PDOF) in a yawing vehicle is also discussed.

In this paper the characteristics of on-road rollover accidents are discussed. Typical rollover scenarios are presented and the phases of rollover leading up to and including vehicle trip are reviewed. Test data from various vehicle handling test programs are reviewed. The data from a test program that included maneuvers through an obstacle avoidance course are reviewed in detail. This program included tests in which the vehicle successfully traversed the course as well as tests where intentional vehicle tip-ups occurred. Comparisons of the driver input data (steering wheel angle amplitude and steering wheel rate) and vehicle response data (lateral acceleration, yaw rate, body roll angle and roll rate) from this program are presented. A review of previous analytical models of the rollover trip phase is also included. The applicability of these models in estimating the energy dissipation/transfer and lateral impulse leading to vehicle tip-up in an on road rollover is discussed.

Concrete Median Barriers (CMB’s) are used extensively on the roadways of North America. They are most often used as permanent barriers on major freeways and highways and as temporary barriers in roadway construction zones. A drive along most stretches of roadway where CMB’s are in use will reveal multiple instances of automobile impact evidence. In this paper the characteristics of automobile impacts with CMB’s are analyzed. Specifically, the case of a yawing, side-slipping vehicle impact, where significant frontal engagement may occur, is considered. Typical damage patterns and residual crush profiles are reviewed as well as vehicle Delta-V, and Barrier Equivalent Velocity (BEV). Frictional energy losses, due to vehicle and CMB interaction, and their significance in the reconstruction of this type of collision are discussed. The vertical velocity component induced by the CMB in this type of impact is also examined.

Laboratory testing measured the response of a 1984 Chevrolet S-10 Blazer seatbelt buckle to impact on the back of the buckle. The peak acceleration, pulse duration and webbing tension were recorded to map the unique circumstances necessary to inertially unlatch the buckle. The conditions necessary to inertially unlatch the buckle in the laboratory were compared with the measured buckle responses in fifteen sled tests and six rollover crash tests using anthropomorphic dummies. All of the crash tested buckles remained latched and all had dynamic responses well below those required to produce inertial unlatching. Dummy hip areas were measured to be significantly stiffer than humans. Buckle accelerations measured in the “parlor trick” of intentionally striking the hip with a buckle are not representative of crash conditions.

Neither the experimental nor analytical techniques currently used to study vehicle rollover accidents accurately represent most actual rollovers. Until recently, crash tests to study rollovers have used either snubbed dollies or guided ramps to cause rollovers. Real world vehicle rollovers, however, are caused by a variety of mechanisms, including impacting curbs or obstacles, sliding through soil or sod, and dropping off embankments. Analytical methods proposed to model rollover events represent idealized curb trip situations and provide unrealistically low estimates for the lateral speeds needed to cause rollovers. This paper presents the results of a continuing investigation into the mechanics of real world vehicle rollovers. Rollover tests with vehicles tripped by a curb, sliding in soil, and thrown from a dolly are presented. The mechanics of the different trip modes is discussed and a simple analytical model to represent the trip mode behavior presented.

This paper reviews the development and demonstration of a procedure for a rollover test to be conducted without the use of a ramp or rollover cart and also demonstrates the kinematics of an unrestrained far side occupant during the rollover sequence. A full-size car was pulled sideways into an energy absorbing barrier causing the car to roll 180 degrees and yaw 360 degrees. The test demonstrated that in an event of this type and severity, the injury can occur prior to ejection and that there is no correlation between roof crush and injury.