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Vehicle front-end geometry and stiffness characteristics have been shown to influence pedestrian lower extremity response and injury patterns. The goal of this study is to compare the lower extremity response and injuries of post mortem human surrogates (PMHS) tested in full-scale vehicle-pedestrian impact experiments with a small sedan and a large sport utility vehicle (SUV). The pelves and lower limbs of six PMHS were instrumented with six-degree-of-freedom instrumentation packages. The PMHS were then positioned laterally in mid-stance gait and subjected to vehicle impact at 40 km/h with either a small sedan (n=3) or a large SUV (n=3). Detailed descriptions of the pelvic and lower extremity injuries are presented in conjunction with global and local kinematics data and high speed video images. Injured PMHS knee joints reached peak lateral bending angles between 25 and 85 degrees (exceeding published injury criteria) at bending rates between 1.1 deg/ms and 3.7 deg/ms.

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.

In crashes between heavy trucks and light vehicles, most of the fatalities are the occupants of the light vehicle. A reduction in heavy truck stopping distance should lead to a reduction in the number of crashes, the severity of crashes, and consequently the numbers of fatalities and injuries. This study made use of the National Advanced Driving Simulator (NADS). NADS is a full immersion driving simulator used to study driver behavior as well as driver-vehicle reactions and responses. The vehicle dynamics model of the existing heavy truck on NADS had been modified with the creation of two additional brake models. The first was a modified S-cam (larger drums and shoes) and the second was an air-actuated disc brake system. A sample of 108 CDL-licensed drivers was split evenly among the simulations using each of the three braking systems. The drivers were presented with four different emergency stopping situations.

Since 1994, the New Car Assessment Program (NCAP) of the National Highway Traffic Safety Administration (NHTSA) has compiled upper neck loads for the belt and air bag restrained 50th percentile male Hybrid III dummy. Over five years from 1994 to 1998, in frontal crash tests, NCAP collected upper neck data for 118 passenger cars and seventy-eight light trucks and vans. This paper examines these data and attempts to assess the potential for neck injury based on injury criteria included in FMVSS No. 208 (for the optional sled test). The paper examines the extent of serious neck injury in real world crashes as reported in the National Automotive Sampling System (NASS). The results suggest that serious neck injuries do occur at higher speeds for crashes involving occupants restrained by belts in passenger cars.

This paper presents the details of the model for the physical steering system used on the National Advanced Driving Simulator. The system is basically a hardware-in-the-loop (steering feedback motor and controls) steering system coupled with the core vehicle dynamics of the simulator. The system's torque control uses cascaded position and velocity feedback and is controlled to provide steering feedback with variable stiffness and dynamic properties. The reference model, which calculates the desired value of the torque, is made of power steering torque, damping function torque, torque from tires, locking limit torque, and driver input torque. The model also provides a unique steering dead-band function that is important for on-center feel. A Simulink model of the hardware/software is presented and analysis of the simulator steering system is provided.

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.

This paper focuses on the overall structure of the Crash Injury Research and Engineering Network (CIREN), how data are collected, and what makes it unique. It discusses how it can be used to expand and enhance the information in other databases. CIREN is a collaborative effort to conduct research on crashes and injuries at nine Level 1 Trauma Centers which are linked by a computer network. Researchers can review data and share expertise, which will lead to a better understanding of crash injury mechanisms and the design of safer vehicles. CIREN data are being used in outreach and education programs on motor vehicle safety. CIREN outreach and education has already been credited with lifesaving information dissemination.

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.

This paper attempts to define and measure factors related to a vehicle's performance that are influential in the causation of rollover accidents. Data are presented which define the rollover involvement rates for many non-vehicular factors. A brief description of the vehicle metrics and the analysis procedures used in the rollover prevention rulemaking program are included along with a set of conclusions. The program evaluated many vehicle metrics related to vehicle rollover, analyzed accidents from 5 states, and compared the two data bases by testing “cause and effect” hypotheses by performing statistical regressions to determine levels of correlation. Location of the crash, urban vs. rural, was a strong predictor of the crash outcome - that is, rollover or non-rollover. Vehicle class and single vehicle accident rate were also statistically significant, as well as, whether or not the vehicle was equipped with anti-lock brakes. Several other driver demographics were significant.

When a heavy vehicle driver (or in fact a driver of any vehicle) makes a brake application that is too "hard" for conditions - especially when the vehicle is lightly loaded or empty and/or the road is wet or slippery - he is likely to lock some or all of his wheels. Under these conditions, the tractor can jackknife or the trailer can swing out of its lane (if it is a combination-unit vehicle) or the truck can spin out (if it is a single-unit vehicle). Incorporation of an antilock brake system addresses the wheel lock and resultant control loss.

Injuries to the thorax and abdomen comprise a significant percentage of all occupant injuries in motor vehicle accidents. While the percentage of internal chest injuries is reduced for restrained front-seat occupants in frontal crashes, serious skeletal chest injuries and abdominal injuries can still result from interaction with steering wheels and restraint systems. This paper describes the design and performance of prototype components for the chest, abdomen, spine, and shoulders of the Hybrid III dummy that are under development to improve the capability of the Hybrid III frontal crash dummy with regard to restraint-system interaction and injury-sensing capability.

Finite element modelling has been used to study the evolution of strain in a model of the human brain under impulsive acceleration loadings. A cumulative damage measure, based on the calculation of the volume fraction of the brain that has experienced a specific level of stretch, is used as a possible predictor for deformation-related brain injury. The measure is based on the maximum principal strain calculated from an objective strain tensor that is obtained by integration of the rate of deformation gradient with appropriate accounting for large rotations. This measure is used here to evaluate the relative effects of rotational and translational accelerations, in both the sagittal and coronal planes, on the development of strain damage in the brain. A new technique for the computational treatment of the brain-dura interface is suggested and used to alleviate the difficulties in the explicit representation of the cerebrospinal fluid layer existing between the two solid materials.

A proposed modification to the Hybrid III 50th percentile male dummy upper femur appears to reduce the chest response problems resulting from femur-pelvis interaction in test exposures more severe than Standard No. 208 testing. When compared to overall repeatability of tests, the modification did not change other dummy response measurements appreciably. The femur-pelvis interaction problem, referred to as “hip lock”, was thought to occur in certain vehicles when the femurs of a passenger side dummy impacting only an air bag bottomed out against the pelvis structure. If metal-to-metal contact occurred, excessive load could be transferred to the chest, leading to elevated chest responses. The most pertinent signs of hip lock occurring appear to be a large, sharply pointed z chest acceleration, and a distinct positive component of the lumbar spine z force following the main negative component.

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.

The paper reviews one hundred and three (103) cases of restrained children involved in motor vehicle crashes and admitted to the level I trauma center at Children's National Medical Center (CNMC). Thirty percent (30%) of these cases involved injuries with an Abbreviated InjuryScore (AIS) severity of 3 or greater. All cases are classified first by type of restraint system, i.e. infant seat, convertible seat, booster seat, lap belt, and lap and shoulder belt, and second, by type of injury sustained, i.e. head/face and neck, upper extremity, thorax, pelvic and abdominal, and lower extremity. The links between these classifications are examined to identify particular injury patterns associated with the use of individual restraint systems, e.g. the incidence of pelvic and abdominal injury associated with the use of both lap and lap and shoulder belts. For the severe injury cases the paper further examines the injury mechanisms for the most commonly observed patterns.

The number of passenger vehicles with combined 3-point belt/driver air bag restraint systems is steadily increasing. To investigate the effectiveness of this restraint combination, 48 kph frontal collisions were performed with human cadavers. Each cadaver's thorax was instrumented with a 12-accelerometer array and two chest bands. The results show, that by using a combined standard 3-point belt (6% elongation)/driver air bag, the thoracic injury pattern remained located under the shoulder belt. The same observation was found when belts with 16% elongation were used in combination with the driver air bag. Chest contours derived from the chest bands showed high local compression and deformation of the chest along the shoulder belt path, and suggest the mechanism for the thoracic injuries.

In the United States, air bags will be required in all passenger cars and light trucks under Federal Motor Vehicle Safety Standard (FMVSS) No. 208, Occupant Crash Protection. Even after full implementation of driver and passenger air bags as required by FMVSS No. 208, frontal impacts will still account for up to 8,000 fatalities and 120,000 moderate to critical injuries (i.e., injuries of AIS ≥ 2) [1]. The National Highway Traffic Safety Administration (NHTSA) has an ongoing research program to address these fatalities and injuries and provide a basis for the possible future upgrade of FMVSS No. 208. This effort includes developing supplementary test procedures for the evaluation of occupant injury in higher severity crashes, developing improved injury criteria including criteria for assessing injuries to additional body regions, and evaluating the injuries associated with occupant size [2, 3 and 4].

A study of frontal collisions using the NASS data base showed that there were four times as many arm injuries to belt restrained drivers who had an air bag deploy than for the drivers who were simply belted. By far, the distal forearm/hand was the most commonly injured region. Hard copy review identified two modes of arm injury related to the deploying air bag: 1) The arm is directly contacted by the air bag module and/or flap cover, and 2) The arm is flung away and contacts an interior car surface. Based on the field studies, a mechanical device called the Research Arm Injury Device (RAID) was fabricated to assess the aggressivity of air bags from different manufacturers. Results from static air bag deployment tests with the RAID suggested that the RAID was able to clearly distinguish between the aggressive and non-aggressive air bags. Maximum moments ranging between 100 Nm and 650 Nm, and hand fling velocity ranging between 30 and 120 km/h were measured on the RAID in these tests.

Assessment of potential forearm fracture due to deployment of driver air bags is examined through a series of static air bag deployments with a specially instrumented Hybrid III dummy. The objective of the study was to determine the feasibility of measuring accelerations and bending moments on the Hybrid III dummy forearm as a potential injury index for arm fracture. Study of the National Accident Sampling System data has shown that in isolated circumstances, deployment of an air bag while the driver is making a turn can lead to fractures of the lower arm. To examine this phenomenon, the Hybrid III dummy was instrumented with accelerometers and strain gages to allow measurement of the accelerations and moments on the right arm. The arm was oriented over the steering wheel towards the eleven o'clock position during deployment of the air bag. Accelerations were measured on the arm at the wrist, elbow, and shoulder. Moments in two axes were measured at two locations below the elbow.

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.