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In vehicle crash accidents, approximately 27% to 30% of passenger car occupant casualties are attributed to side impact accidents. The annual death toll in side impacts for passenger car occupants reached 9,000 in 1975 and 1976 and has been between 7,000 and 8,000 in the 1980's. Since 1977, the National Highway Traffic Safety Administration (NHTSA) and many other groups have conducted a significant amount of research on occupant side impact protection with emphasis on thorax injury reduction. Three important problem areas in the side impact are (1) thorax-to-side interior impact, (2) head impacts with A-pillar/roof rail components and (3) occupant ejection through side doors/windows. While the first problem area has been thoroughly studied, the remaining two areas are seldom discussed and less well understood. Therefore, they are relatively new areas to many people.

This paper describes computer crash simulations performed by the National Highway Traffic Safety Administration (NHTSA) under the current research and testing activities on large school bus safety restraints. The simulations of a frontal rigid barrier test and comparative dynamic sled testing for compartmentalization, lap belt, and lap/shoulder belt restraint strategies are presented. School bus transportation is one of the safest forms of transportation in the United States. School age children transported in school buses are safer than children transported in motor vehicles of any other type. Large school buses provide protection because of their size and weight. Further, they must meet minimum Federal motor vehicle safety standards (FMVSSs) mandating compartmentalized seating, improved emergency exits, stronger roof structures and fuel systems, and better bus body joint strength.

The facial laceration test has been proposed as an addition to the dummy injury criteria of Federal Motor Vehicle Safety Standard 208. To better understand laceration conditions as they actually occur, three road crashes of increasing severity, all involving facial laceration by the broken (cracked) windshield and one involving partial ejection, have been simulated physically and analytically. The physical simulations used vehicle test bucks, the Hybrid III head with the chamois facial coverings of the facial laceration test, and a piston - constrained Head Impactor. Computer simulations of the three crashes were also carried out using the CALSPAN 3D “CVS” and the 2D “DRISIM” computer programs. The computer simulations provide insight into the effective mass of the head and body on windshield contact, and the forces, velocities, and accelerations involved.

The protection of a vehicle occupant in a frontal crash is a combination of vehicle front structural design and occupant restraint design. Once chosen and manufactured, these design features must interact with a wide variety of structural characteristics in potential crash partners. If robust, the restraint design will provide a high level of protection for a wide variety of crash conditions. This paper examines how robust a given restraint system is for occupant self-protection and how frontal design can improve the restraint performance of potential crash partners, thus improving their restraint robustness as well. To examine restraint robustness in self protection, the effect of various vehicle deceleration characteristics on occupant injury potential is investigated for a given restraint design. A MADYMO model of a 1996 Taurus interior and its restraint system with a Hybrid III 50th percentile male dummy are simulated and subjected to 650 crash pulses taken during 25 years of U.S.

In ISO Technical Report 9790 (1999) normalized lateral and oblique thoracic force-time responses of PMHS subjected to blunt pendulum impacts at 4.3 m/s were deemed sufficiently similar to be grouped together in a single biomechanical response corridor. Shaw et al., (2006) presented results of paired oblique and lateral thoracic pneumatic ram impact tests to opposite sides of seven PMHS at sub-injurious speed (2.5 m/s). Normalized responses showed that oblique impacts resulted in more deflection and less force, whereas lateral impacts resulted in less deflection and more force. This study presents results of oblique and lateral thoracic impacts to PMHS at higher speeds (4.5 and 5.5 m/s) to assess whether lateral relative to oblique responses are different as observed by Shaw et al., or similar as observed by ISO.

Pedestrian research and testing at the NHTSA Vehicle Research and Test Center has recently focused on assessment of proposed ISO and EEVC head impact test procedures, and extension of these procedures to additional vehicle frontal surfaces. In addition to test parameter sensitivity evaluation, reconstruction of PCDS (Pedestrian Crash Data Study) cases with laboratory impact tests and computer simulations has been conducted. This paper presents the results of this research.

The paper discusses the development of a model for a 1998 Chevrolet Malibu for the National Advanced Driving Simulator’s (NADS) vehicle dynamics simulation, NADSdyna. The Malibu is the third vehicle modeled for the NADS, and this is the third paper dealing with model development. SAE Paper 970564 contains details of the model for the 1994 Ford Taurus and SAE Paper 1999–01-0121 contains details of the model for the 1997 Jeep Cherokee. The front and rear suspensions are independent strut and link type suspensions modeled using recursive rigid body dynamics formulations. The suspension springs and shock absorbers are modeled as elements in the rigid body formulation. To complement the vehicle dynamics for the NADS application, subsystem models that include tire forces, braking, powertrain, aerodynamics, and steering are added to the rigid body dynamics model. The models provide state-of-the-art high fidelity vehicle handling dynamics for real-time simulation.

The paper discusses the development of a model for the 2006 BMW 330i for the National Advanced Driving Simulator's (NADS) vehicle dynamics simulation, NADSdyna. The front and rear suspensions are independent strut and link type suspensions modeled using recursive rigid-body dynamics formulations. The suspension springs and shock absorbers are modeled as force elements. The paper includes parameters for front and rear semi-empirical tire models used with NADSdyna. Longitudinal and lateral tire force plots are also included. The NADSdyna model provides state-of-the-art high-fidelity handling dynamics for real-time hardware-in-the-loop simulation. The realism of a particular model depends heavily on how the parameters are obtained from the actual physical system. Complex models do not guarantee high fidelity if the parameters used were not properly measured. Methodologies for determining the parameters are detailed in this paper.

The National Highway Traffic Safety Administration (NHTSA) is conducting a research program to investigate the use of the 40 percent offset deformable barrier (ODB) crash test procedure to reduce death and injury, in particular debilitating lower extremity injuries in frontal offset collisions. This paper presents the results of 22 ODB crash tests conducted with 50th percentile male and 5th percentile female Hybrid III (HIII) dummies fitted with advanced lower legs, Thor-Lx/HIIIr and Thor-FLx/HIIIr, to assess the potential for debilitating and costly lower limb injuries. This paper also begins to investigate the implications that the ODB test procedure may have for fleet compatibility by evaluating the results from vehicle-to-vehicle crash tests.

This paper presents an overview of NHTSA's vehicle aggressivity and fleet compatibility research activities. This research program is being conducted in close cooperation with the International Harmonized Research Agenda (IHRA) compatibility research group. NHTSA is monitoring the changing vehicle mix in the U.S. fleet, analyzing crash statistics, and evaluating any implications that these changes may have for U.S. occupant safety. NHTSA is also continuing full-scale crash testing to develop a better understanding of vehicle compatibility and to investigate test methods to assess vehicle compatibility.

NHTSA uses a variety of computer modelling techniques to develop and evaluate test methods and mitigation concepts, and to estimate safety benefits for many of NHTSA's research activities. Computer modeling has been particularly beneficial for estimating safety benefits where often very little data are available. Also modeling allows researchers to augment test data by simulating crashes over a wider range of conditions than would otherwise be feasible. These capabilities are used for a wide range of projects from school bus to frontal, side, and rollover research programs. This paper provides an overview of these activities. NHTSA's most extensive modeling research involves developing finite element and articulated mass models to evaluate a range of vehicles and crash environments. These models are being used to develop a fleet wide systems model for evaluating compatibility issues.

This paper presents an overview of work performed by the National Highway Traffic Safety Administration's (NHTSA) Vehicle Research and Test Center (VRTC) to test, validate, and improve the planned National Advanced Driving Simulator's (NADS) vehicle dynamics simulation. This vehicle dynamics simulation, called NADSdyna, was developed by the University of Iowa's Center for Computer-Aided Design (CCAD) NADSdyna is based upon CCAD's general purpose, real-time, multi-body dynamics software, referred to as the Real-Time Recursive Dynamics (RTRD), supplemented by vehicle dynamics specific submodules VRTC has “beta tested” NADSdyna, making certain that the software both works as computer code and that it correctly models vehicle dynamics. This paper gives an overview of VRTC's beta test work with NADSdyna. The paper explains the methodology used by VRTC to validate NADSdyna.

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.

Early influences upon Thor ATD development are described, and the path of Thor development is traced up to the release of the current Thor ALPHA ATD design. Since the display of the first Thor ATD prototype at the 15th ESV Conference in Melbourne in 1996, Thor has undergone extensive test and evaluation on an international basis in cooperation with many partner institutions. This paper summarizes some of the lessons learned from this broad test experience, and documents actions which have been undertaken to upgrade the Thor product to ALPHA status in light of this experience.

Several thoracic and head protection side impact air bag systems (SAB) are emerging in the U.S. market and are projected to become prevalent in the fleet. These systems appear to offer superior protection in side crashes. However, concerns have been raised as to their potential for causing injury to out-of-position (OOP) occupants. This paper describes the National Highway Traffic Safety Administration (NHTSA) program for evaluation of the SAB systems for OOP occupants and provides a status report on the current research. The industry's Side Airbag Out-of- Position Injury Technical Working Group (TWG) recommended procedures for 3-year-old and 6-year-old occupants are evaluated. Additional test procedures are described to augment the TWG procedures for these occupants and 12-month- old infants.

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.

A new lower leg/ankle/foot system has been designed and fabricated to assess the potential for lower limb injuries to small females in the automotive crash environment. The new lower extremity can be retrofitted at present to the distal femur of the 5th percentile female Hybrid III dummy. Future plans are for integration of this design into the 5th percentile female THOR dummy now under development. The anthropometry of the lower leg and foot is based mainly on data developed by Robbins for the 5th percentile female, while the biomechanical response requirements are based upon scaling of 50th percentile male THOR-Lx responses. The design consists of the knee, tibia, ankle joints, foot, a representation of the Achilles tendon, and associated flesh/skins. The new lower extremity, known as THOR-FLx, is designed to be biofidelic under dynamic axial loading of the tibia, static and dynamic dorsiflexion, static plantarflexion and inversion/eversion.

This paper presents an approach for evaluating the effects of brake system component degradation on vehicle braking performance. The approach involves the use of an inertial brake dynamometer, vehicle computer simulation, and vehicle test. The approach, procedures, and results of the study of the effects of worn friction materials, worn discs and drums, and contaminated brakes are presented.

A major focus of the National Highway Traffic Safety Administration's (NHTSA) vehicle compatibility and aggressivity research program is the development of a laboratory test procedure to evaluate compatibility. This paper is written to explain the associated goals, issues, and design considerations and to review the preliminary results from this ongoing research program. One of NHTSA's activities supporting the development of a test procedure involves investigating the use of an mobile deformable barrier (MDB) into vehicle test to evaluate both the self-protection (crashworthiness) and the partner-protection (compatibility) of the subject vehicle. For this development, the MDB is intended to represent the median or expected crash partner. This representiveness includes such vehicle characteristics as weight, size, and frontal stiffness. This paper presents distributions of vehicle measurements based on 1996 fleet registration data.

The frontal crash standard in the USA specifies that the full front of a vehicle impact a rigid barrier. Subsequently, the European Union developed a frontal crash standard that requires 40 percent of the front of a vehicle to impact a deformable barrier. The present study conducted paired crashes of vehicles using the full-frontal barrier procedure and the 40 percent offset deformable barrier procedure. In part, the study was to examine the feasibility of adding an offset test procedure to the frontal crash standard in the USA. Frontal-offset and full-frontal testing was conducted using both the mid-size (50th percentile male Hybrid III) and the small stature (5th percentile female Hybrid III) dummies. Five vehicle models were used in the testing: Dodge Neon, Toyota Camry, Ford Taurus, Chevrolet Venture and Ford Contour. In the crash tests, all dummies were restrained with the available safety belt systems and frontal air bags.