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This paper presents the test track scenario design and analysis used to estimate the performances of heavy vehicles equipped with forward collision warning and automatic emergency braking systems in rear-end crash scenarios. The first part of this design and analysis study was to develop parameters for brake inputs in test track scenarios simulating a driver that has insufficiently applied the brakes to avoid a rear-end collision. In the second part of this study, the deceleration limits imposed by heavy vehicles mechanics and brake systems are used to estimate automatic emergency braking performance benefits with respect to minimum stopping distance requirements set by Federal Motor Vehicle Safety Standards. The results of this study were used to complete the test track procedures and show that all heavy vehicles meeting regulatory stopping distance requirements have the braking capacity to demonstrate rear-end crash avoidance improvements in the developed tests.

The objective of this paper is to describe the general methodology used by NHTSA to perform cost-effectiveness analyses and cost-benefit analyses. This general method will then be directed towards how one could analyze fire countermeasures, providing two analyses as examples. First, for crash related fires, NHTSA's 2003 analysis on fuel tank integrity will be used. Second, for non-crash related fires, NHTSA's 2001 analysis of radiator caps will be used. The paper will describe what data sources were used to determine the target population, the severity of injuries, the costs of burns by injury severity, the cost of the fire countermeasures, etc. While not analyzing any specific fire countermeasure, the methodology will be described in enough detail that others could potentially follow the methodology and make estimates for their own purposes.

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 injury outcome of a front-front two-vehicle crash will be a function of crash-specific, vehicle-specific, and occupant-specific parameters. This paper focuses on a preliminary methodology that was used to evaluate the potential for benefits in making vehicle-specific changes to improve the compatibility of light vehicles across the fleet. In particular, the effect on injury rates of matching vehicle frontal stiffness was estimated. The front-front crash data for belted drivers in the lighter vehicles in the crash from ten years of NASS-CDS data were examined. The frontal stiffness of each vehicle was calculated using data taken during full frontal rigid barrier tests for the U.S. New Car Assessment Program (NCAP), and only crashes coded in the CDS as “no override” were considered.

In September 2009 the National Highway Traffic Safety Administration (NHTSA) published a report that investigated the incidence of fatalities to belted non-ejected occupants in frontal crashes involving late-model vehicles. The report concluded that after exceedingly severe crashes, the largest number of fatalities occurred in crashes involving poor structural engagement between the vehicle and its collision partner, present in crashes characterized as corner impacts, oblique crashes, impacts with narrow objects, and heavy vehicle underrides. By contrast, few if any of these 122 fatal crashes were full-frontal or offset-frontal impacts with good structural engagement, excepting crashes that were of extreme severity or the occupants that were exceptionally vulnerable. The intent of this research program is to develop a test protocol that replicates real-world injury potential in small overlap impacts (SOI) and oblique offset impacts (Oblique) in motor vehicle crashes.

The purpose of the study was to distinguish the role of vehicle structure in frontal impacts in published coded National Automotive Sampling System (NASS-CDS) data. The criteria used: Collision Deformation Classification (CDC) coding rules, crush profile locator data and the projected location of longitudinal structural members in models of vehicle class sizes used by NASS-CDS. Two classifiers were developed to augment the CDC system. The Coincidence classifier indicates the relationship between the quadrant of the clock face the crash vector originates in and the aspect of the end plane the center of damage is located. It has three values: Linear (12 o'clock impacts) Consistent and Variant ("oblique" Principal Directions of Force or PDOFs). The second classifier indicates the number of longitudinal members engaged: 0, 1 or 2. NASS-CDS data for sample years 2005 to 2009 was filtered for occupants involved in impacts with the highest ranked speed change assigned to the front-end plane.

Modern optical diagnostics such as laser induced fluorescence (LIF) offer considerable assistance in developing effective computational capabilities for complex reactive flows. Applications of these selective, spatially-resolved, non-intrusive technologies include model verification, input parameters, and kinetic simplifications for complex calculations. Pertinent examples from our current diagnostics development and flame applications are reviewed with an emphasis on the chemical implications to advanced computational dynamics for engines. Raman, LIF, and chemiluminescence diagnostics are discussed; potential diagnostics applications include fluid mixing, pollutants, knock, flame front location, and temperature measurement.

Objectives. Examination of head injuries in the Pedestrian Crash Data Study (PCDS) indicates that many pedestrian head injuries are induced by a combination of head translation and rotation. The Simulated Injury Monitor (SIMon) is a computer algorithm that calculates both translational and rotational motion parameters relatable head injury. The objective of this study is to examine how effectively HIC and three SIMon correlates predict the presence of either their associated head injury or any serious head injury in pedestrian collisions. Methods. Ten reconstructions of actual pedestrian crashes documented by the PCDS were conducted using a combination of MADYMO simulations and experimental headform impacts. Linear accelerations of the head corresponding to a nine-accelerometer array were calculated within the MADYMO model's head simulation.

Recently there has been a greater awareness of the increased risk of certain injuries associated with air bag deployment, especially the risks to small occupants, often women. These injuries include serious eye and upper extremity injuries and even fatalities. This study investigates the interaction of a deploying air bag with cadaveric upper extremities in a typical driving posture; testing concentrates on female occupants. The goals of this investigation are to determine the risk of upper extremity injury caused by primary contact with a deploying air bag and to elucidate the mechanisms of these upper extremity injuries. Five air bags were used that are representative of a wide range of air bag ‘aggressivities’ in the current automobile fleet. This air bag ‘aggressivity’ was quantified using the response of a dummy forearm under air bag deployment.

This paper discusses the consumer and news media perceptions about air bags that had to be taken into account by the National Highway Traffic Safety Administration in making rulemaking decisions in 1997. Addressing these perceptions was a major concern as the agency made preparations to allow identifiable groups of people at risk from an air bag deployments to have on-off switches installed in their vehicles.

The fatigue performance of fillet-welded transverse attachments was compared for several procedure variants for both FCAW and SAW on ½ in. steel plates. Measurements of weld toe shape on adjacent pieces of weld indicated that smoother weld toes, as evidenced by larger weld toe radius, were correlated to improved fatigue performance for both processes. Fatigue tests conducted on 59 and 109 ksi yield strength plates did not show an effect of plate strength. Weld procedures designed to provide smooth toes, such as reduced parameter FCAW beads at horizontal weld toes and flat position FCAW at higher heat inputs, were shown to provide fatigue performances near post-weld improved fillets.

Many automotive production plants are using various prepulse schedules for resistance spot welding thin gauge galvanized steel. The claimed reasons are that wider current range and longer electrode life are obtainable in comparison to the conventional schedule. However, data to support this are not available. The objective of this program was to determine the effect of prepulsation on spot weldability of galvanized steel. In this work, several prepulse resistance spot welding schedules were evaluated in two full factorial experiments. The effect of the number of prepulse cycles, the prepulse heat level and the effect of cool time were studied in detail. Weldability was evaluated using an electrode life test procedure in which the current range was periodically examined over the life of the electrodes. Generally, the results indicate that prepulsation has a negative effect on the resistance spot weldability of thin gauge galvanized steel.

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 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.

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.

Deformation Resistance Welding (DRW) is a process that employs resistance heating to raise the temperature of the materials being welded to the appropriate forging range, followed by shear deformation which increases the contacting surface area of the materials being welded. Because DRW is a new process, it became desirable to establish variable selection strategies which can be integrated into a production procedure. A factorial design of experiment was used to examine the influence of force, number of pulses, and weld cycles (heating/cooling time ratio) on the DRW process. Welded samples were tensile tested to determine their strength. Once tensile testing was complete, the resulting strengths were observed and compared to corresponding percent heat and percent reduction in thickness. Tensile strengths ranged from 107 kN to 22.2 kN. A relationship between the maximum current and the weld variables was established.

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.

On-board Camera/Video Imaging Systems (C/VISs) for heavy vehicles display live images to the driver of selected areas to the sides, and in back of the truck's exterior using displays inside the truck cabin. They provide a countermeasure to blind-spot related crashes by allowing drivers to see objects not ordinarily visible by a typical mirror configuration, and to better judge the clearance between the trailer and an adjacent vehicle when changing lanes. The Virginia Tech Transportation Institute is currently investigating commercial motor vehicle (CMV) driver performance with C/VISs through a technology field demonstration sponsored by the National Highway Traffic Safety Administration (NHTSA) and the Federal Motor Carrier Safety Administration (FMCSA). Data collection, which consists of recording twelve CMV drivers performing their daily employment duties with and without a C/VIS for four months, is currently underway.

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.