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Based on a long recognized need, the National Highway Traffic Safety Administration (NHTSA) has begun to reexamine the potential for international harmonization of side impact requirements. To this end, NHTSA, as directed by the U.S. Congress, has recently submitted a report to the Congress on the agency plans for achieving harmonization of the U.S. and European side impact regulations. The first phase of this plan involves crash testing vehicles compliant to FMVSS 214 to the European Union side impact directive 96/27/EC. This paper presents the results to date of this research. The level of safety performance of the vehicles based on the injury measures of the European and U.S. side impact regulations is assessed.

Since 1990, the National Highway Traffic Safety Administration (NHTSA) implemented a dynamic side impact compliance test. This compliance test, Federal Motor Vehicle Safety Standard (FMVSS) No. 214, is a nearly right angle side impact in which the striking vehicle moves at 53.6 kmph into the struck vehicle. In 1997, NHTSA began testing passenger cars in side impact in the New Car Assessment Program (NCAP). In the USA NCAP side impact, the striking vehicle is towed at a 8 kmph higher speed than in the compliance test. An analysis has begun on the data from the first NCAP side impact tests, thirty-two in number. In the crashes, accelerometers were installed in the door and door frames of the struck vehicle. Using the accelerometers on the vehicle structure and in the side impact dummy, the crash event was investigated. One tool used in the investigation was the velocity-versus-time diagram.

NHTSA conducted seventy-six side impact FMVSS No. 214 compliance tests from 1994 through 1997. The compliance tests are nearly right angle side impacts with low longitudinal components of change of velocity (Δv). Frontal air bag deployments were found to have occurred for 34% of the driver bags and 32% of the front passenger bags in these compliance-tested passenger cars. In 1997, NHTSA began testing passenger cars 'in side impact in the New Car Assessment Program (NCAP). The NCAP crash tests are conducted at a higher speed than the compliance tests. The cars in the NCAP side impact tests also had low longitudinal components of Δv. Approximately 40% of the twenty-six passenger cars tested in the 1997 Side Impact NCAP had their frontal air bags deploy. Real world crash data were examined to determine if frontal air bags are deploying in right angle side impacts on the roads of the US.

The National Highway Traffic Safety Administration has initiated research to develop performance specifications for dummy-based accelerometers in the crash test environment, and to provide criteria for defining and establishing equivalent performance among accelerometers from different manufacturers. These research efforts are within the general guidelines on transducer equivalency outlined in the current revision of the Society of Automotive Engineers recommended practice, Instrumentation for Impact Test, SAE 211/2 March 1995. Representative data from vehicle crash and component level tests have been analyzed to determine the acceleration levels and frequency content in a realistic dynamic environment for dummy-based accelerometers.

Computational simulations are conducted for several head impact scenarios using a three dimensional finite element model of the human brain in conjunction with accelerometer data taken from crash test data. Accelerometer data from a 3-2-2-2 nine accelerometer array, located in the test dummy headpart, is processed to extract both rotational and translational velocity components at the headpart center of gravity with respect to inertial coordinates. The resulting generalized six degree-of-freedom description of headpart kinematics includes effects of all head impacts with the interior structure, and is used to characterize the momentum field and inertial loads which would be experienced by soft brain tissue under impact conditions. These kinematic descriptions are then applied to a finite element model of the brain to replicate dynamic loading for actual crash test conditions, and responses pertinent to brain injury are analyzed.

Locations of key body segments of Hybrid III dummies used in FMVSS 208 compliance tests and NCAP tests were measured and subjected to statistical analysis. Mean clearance dimensions and their standard deviations for selected body segments of driver and passenger occupants with respect to selected vehicle surfaces were determined for several classes of vehicles. These occupant locations were then investigated for correlation with impact responses measured in crash tests and by using a three dimensional human-dummy mathematical model in comparable settings. Based on these data, the importance of some of the clearance dimensions between the dummy and the vehicle surfaces was determined. The study also compares observed Hybrid III dummy positions within selected vehicles with real world occupant positions reported in published literature.

This paper describes the results of a study conducted to evaluate the performance and accuracy of a medium size sedan finite element model for off-set car-to-car impacts. This model was originally developed for front impact and does not include side structure compliance. Two tests conducted by the National Highway Traffic Safety Administration are used for evaluation of the simulations. The overall results indicate that the simulations appear to be consistent with the crash test data. Problems associated with the use of node constraints, lack of side structure model fidelity, and the different integration time marching are identified and solutions for the problems are proposed.

This report is a condensed version of the December 1993 New Car Assessment Program (NCAP) report to Congress and provides: an historical review and future goals for NCAP. the results of an 18-month study to assess consumer and media needs in understanding and promoting the use of NCAP data. This included consumer focus groups and media studies. These studies indicated that consumers and the media desire comparative safety information on vehicles, a simplified NCAP format to better understand and utilize the crash test results, and would like to see NCAP expanded to include other crash modes. studies of real-world crashes versus NCAP crash tests. These studies conclude that NCAP test conditions approximate real-world crash conditions covering a major segment of the frontal crash safety problem and that there is a significant correlation between NCAP results and real-world fatality risks for restrained drivers.

A review was conducted of injuries associated with ejection through motor vehicle glazing, using the 1988 through 1991 National Accident Sampling System data maintained by the National Highway Traffic Safety Administration. The review indicated that one percent of the occupants in towaway crashes were ejected and that 22 percent of fatalities in towaway crashes were ejected. Fifty-three percent of complete ejections were through the glazing openings in motor vehicles. Current motor vehicle glazing does not contribute significantly to occupant injuries, but the effects of glazing changes on serious injuries will need to be considered.

The SISAME methodology is a system for extracting one-dimensional lumped parameter vehicle crash models from non-oblique crash test data, and for simulation of such models. Model extraction is based on constrained least squares optimization of an overdetermined system of target equations for the model parameters. The SISAME computer program performs extraction and simulation with a number of features that allow user control of the computations and outputs. Additional computer programs perform data assessment/correction and filtering. Experience has shown that the SISAME methodology can efficiently produce predictively useful models that accurately capture the motions of the actual crash event. The essential formulation of SISAME and some sample applications are presented in this paper.

The injury reducing effectiveness of child safety seats in frontal crashes was evaluated, based on 36 frontal or oblique sled tests run with two or more GM three-year-old dummies in the simulated passenger compartment of a car. Unrestrained, correctly restrained and incorrectly restrained dummies were tested at the range of speeds where most nonminor injuries occur (15-35 mph). Accident data from NHTSA files were used to calibrate a relationship between the front-seat unrestrained dummies' HIC and unrestrained children's risk of serious head injuries; also between torso g's and the risk of serious torso injuries. These relationships were used to predict injury risk for the restrained children as a function of crash speed and to compare it to the risk for unrestrained children. The sled test analysis predicted that the 1984 mix of correctly and incorrectly used safety seats reduced serious injury risk by 40 percent relative to the unrestrained child, in frontal crashes.

The absence of data on the load deflection and energy absorption characteristics of vehicle interiors has been a factor which limits the accuracy of crash victim simulations. A recent test program conducted for the National Highway Traffic Safety Administration has developed data on the interactions of dashboards and knee panels with chests and knees. This paper summarizes the test results for several vehicles and shows how these results are used in simulating vehicle crash tests. Comparisons between crash tests and computer reconstruction using the 3-Dimensional Crash Victim Simulator (CVS-3D) for a late model car are included. The simulation shows good agreement with test and illustrates the application of available static and dynamic test data to improve occupant simulations.

The paper presents a comparison of kinematic responses between the MVMA-2D and the MAC-DAN pedestrian models and pedestrian cadaver kinematics observed in staged car/pedestrian impact tests. The paper also discusses the injuries experienced in the cadaver tests. Seven cadaver specimens in the standing posture were impacted at 25 mph by two different cars: one having a steel bumper and the other having a plastic bumper. The MVMA-2D and MAC-DAN mathematical pedestrian models were employed to simulate pedestrian impacts at 25 mph by a vehicle with a stylized geometry that is similar to the vehicles used in cadaver tests. Comparison of the simulations and the cadaver tests show that both models require further refinement to be able to more accurately simulate the kinematics of the lower legs during impacts with the vehicle bumper.

The NHTSA has developed automotive recorders which can measure crash triaxial acceleration/time histories during vehicle collisions. From these acceleration histories (recorded on a magnetic disc), velocity/time histories and velocity change during impact are derived to provide measures of vehicle crash severity. The purpose of developing these recorders is to provide accurate and quantitative relationships of vehicle crash severity with occupant fatalities and serious injuries from real-world accidents. To date, a total of 1200 disc recorders has been produced, approximately 1050 recorders have been installed in fleet vehicles, and 23 accident records have been analyzed. This paper has been prepared to present the progress made in the Disc Recorder Pilot Project as of March 31, 1974. Recorder data from accidents involving vehicles equipped with disc recorders will be discussed and compared with associated reports by accident investigators.