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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.

The National Highway Traffic Safety Administration and the University of Michigan Transportation Institute are investigating truck design countermeasures to provide safety benefits during collisions with light vehicles. The goal is to identify approaches that would best balance costs and benefits. This paper outlines the first phase of this study, an analysis of two-vehicle, truck/light vehicle crashes from 1996 through 1998 using several crash data bases to obtain a current description and determine the scope of the aggressivity problem. Truck fronts account for 60% of light vehicle fatalities in collisions with trucks. Collision with the front of a truck carries the highest probability of fatal (K) or incapacitating (A) injury. Truck sides account for about the same number of K and A-injuries combined as truck fronts, though injury probability is substantially lower than in crashes involving the front of a truck.

The National Highway Safety Administration (NHTSA) is collecting crash data relating to large trucks. Two data collection programs are specified. One is a crash causation study to investigate the cause of fatal and serious large truck crashes over two years. The other study is a continuous effort collecting data on large truck motor carrier crashes in each state, as coded on police accident reports.

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.

In the New Car Assessment Program (NCAP), beginning with the model year 1994 vehicles, the National Highway Traffic Safety Administration (NHTSA) developed and adopted a simplified nonnumeric format for presenting the comparative frontal crashworthiness safety information to consumers. This paper presents the basis for the development of this “star rating” system. The injury probability functions which are used for the star rating system are also applied to the results of the recent NCAP real-world correlation studies and a review of these studies is given. The safety performance for restrained occupants as measured in NCAP is dependent on several parameters which include: the design of the restraint system, the maintenance of the integrity of the occupant space, and the energy management performance of the front structure.

This paper focuses on two types of electronics-based object detection systems for heavy truck applications: those sensing the presence of objects to the rear of the vehicle, and those sensing the presence of objects on the right side of the vehicle. The rearward sensing systems are intended to aid drivers when backing their vehicles, typically at very low “crawl” speeds. Six rear object detection systems that were commercially available at the time that this study was initiated were evaluated. The right side looking systems are intended primarily as supplements to side view mirror systems and as an aid for detecting the presence of adjacent vehicles when making lane changes or merging maneuvers. Four side systems, two commercially available systems and two prototypes, were evaluated.

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].

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.

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.

An important new technique in safety engineering for complex systems is the fault tree analysis method. The results of a motor vehicle brake system safety analysis using the fault tree technique are described. The work is directed toward the identification and ranking of brake system failure modes which may be critical as accident causation factors. Safety criticality for each failure mode is defined as the product of probability of occurrence and severity of effect on vehicle control. Failure data for the brake system components are obtained from maintenance and repair records of a large automobile leasing fleet. An effect scale is developed using a method for pooling expert judgements to obtain the relative ranking of various brake faults as to accident causation potential. The fault tree structure is employed to combine probability and effect to obtain the safety criticality value of each fault.

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 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.

This paper presents an overview of currently ongoing research by the National Highway Traffic Safety Administration (NHTSA) in the area of light vehicle (passenger cars and light trucks) Antilock Brake Systems (ABS). This paper serves as a lead-in to other papers that will be presented during this session. Several statistical crash data studies have found there to be little or no net safety benefit from the implementation of four-wheel ABS on passenger automobiles. Typically, these studies have found ABS to be associated with: 1. A statistically significant decrease in multi-vehicle crashes. 2. A statistically significant decrease in fatal pedestrian strikes. 3. A statistically significant increase in single-vehicle road departure crashes. The safety disbenefit due to the third finding approximately cancels the safety benefits from the first two findings.