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The primary description of crash severity in most accident databases is vehicle delta-V. Delta-V has been traditionally estimated through accident reconstruction techniques using computer codes, e.g. Crash3 and WinSmash. Unfortunately, delta-V is notoriously difficult to estimate in many types of collisions including sideswipes, collisions with narrow objects, angled side impacts, and rollovers. Indeed, approximately 40% of all delta-V estimates for inspected vehicles in the National Automotive Sampling System / Crashworthiness Data System (NASS/CDS) 2001 are reported as unknown. The Event Data Recorders (EDRs), now being installed as standard equipment by several automakers, have the potential to provide an independent measurement of crash severity which avoids many of the difficulties of accident reconstruction techniques. This paper evaluates the feasibility of replacing delta-V estimates from accident reconstruction with the delta-V recorded by EDRs.

The air bag has proven effective in reducing fatalities in frontal crashes with estimated decreases ranging from 11% to 30% depending on the size of the vehicle [IIHS-1995, Kahane-1996]. At the same time, some air bag designs have caused fatalities when front-seat passengers have been in close proximity to the deploying air bag [Kleinberger-1997]. The objective of this study was to develop an accurate and repeatable out-of-position test fixture to study the deployment of air bags into out-of-position occupants. Tests were performed with a 5th percentile female Hybrid III dummy and studied air bag loading on the thorax using draft ISO-2 out-of-position (OOP) occupant positioning. Two different interpretations of the ISO-2 positioning were used in this study. The first, termed Nominal ISO-2, placed the chin on the steering wheel with the spine parallel to the steering wheel.

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.

This paper describes the design and development of a small female crash test dummy, results of biofidelity tests, and preliminary results from full-scale, 3-point belt and airbag type sled tests. The small female THOR was designed using the anthropometric data developed by Robbins for the 5th percentile female and biomechanical requirements derived from scaling the responses of the 50th percentile male. While many of the mechanical components of the NHTSA THOR 50th percentile male dummy were scaled according to the appropriate anthropometric data, a number of improved design features have been introduced in the new female THOR. These include; improved neck design, new designs for the head and neck skins: and new designs for the upper and lower abdomen. The lower leg, ankle and foot, known as THOR-FLx, were developed in an earlier effort and have been included as a standard part of the new female dummy.

The Isodamp damping material (also known as Navy Damp) used in the ribs of current crash test dummies provides human-like damping to the thorax under impact. However, the range of temperature over which it can be used is very small. A new rib design using laminates of steel, fiberglass, and commercially available viscoelastic material has been constructed. Load-deflection response and hysteresis of the laminated ribs were compared with corresponding conventional ribs fabricated from steel and Isodamp. Impact tests were conducted on laminated and conventional ribs at 18.5° C, 22.2° C and 26.6° C. Results indicate that the response of the laminated ribs is essentially the same as that of the ribs with Isodamp at 22.2° C, which is the operating temperature of the conventional ribs. The variation in the impact response of the newly developed laminated ribs in the temperature range of 18.5° C to 26.6° C was less than 10%.

A comparative study between belted rollover occupants who did and did not receive head injuries from roof contact was conducted using the National Accident Sampling System (NASS) database. The main objective was to determine if headroom reduction increases the risk of head injury. Headroom was determined for 155 belted occupants involved in rollover crashes of vehicles which were then weighted to make them representative of national estimates. Results showed that headroom was reduced more in those crashes where the occupant had head injuries than in cases where there were no head injuries. It was concluded that the risk of head injury increased with reduced headroom. Furthermore, it was observed that when the initial headroom was higher, the incidence of head injury was reduced.

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 new lower extremity has been developed to be used with Thor, the NHTSA Advanced Frontal Dummy. The new lower extremity, known as Thor-Lx, consists of the femur, tibia, ankle joints, foot, a representation of the Achilles' tendon and the associated flash/skins, it has been designed to improve biomechanical response under axial loading of the femur during knee impacts, axial loading of the tibia, static and dynamic dorsiflexion, static plantarflexion and inversion/aversion. Instrumentation includes a standard Hybrid ill femur load cell, accelerometers, load cells, and rotary potentiometers to capture relevant kinematic and dynamic information from the foot and tibia. The design also allows the Tnor-Lx to be attached to the Hybrid III, either at the hip, or at the knee.

Postcrash fires are a frequent cause of death in otherwise survivable automobile and aircraft accidents. The idea of the ICED (Internal Circuit Emergency Disconnect) battery [1] is to eliminate electrically ignited postcrash fires by means of an inertial interrupt device that will disconnect the active circuit at the battery if an accident should happen. The design of the prototypes that were tested and the analysis of the disengagement performance will be discussed. A ballistic pendulum impact test rig was designed and used to test the prototypes. The test results and analytical values were shown to be satisfactorily close to each other.

Rotational motion of the head as a mechanism for brain injury was proposed back in the 1940s. Since then a multitude of research studies by various institutions were conducted to confirm/reject this hypothesis. Most of the studies were conducted on animals and concluded that rotational kinematics experienced by the animal's head may cause axonal deformations large enough to induce their functional deficit. Other studies utilized physical and mathematical models of human and animal heads to derive brain injury criteria based on deformation/pressure histories computed from their models.

Forty-two side impact cadaver sled tests were conducted at 24 and 32 km/h impact speeds into rigid and padded walls. The post-mortem human subjects were instrumented with accelerometers on the ribs and spine and chest bands around the thorax and abdomen to characterize their mechanical response during the impact. Load cells at the wall measured the impact force at the level of the thorax, abdomen, pelvis, and lower extremities. The resulting injuries were determined through detailed autopsy and radiography. Rib fractures with or without associated hemo/pneumo thorax or flail chest were the most common injury with severity ranging from AIS=0 to 5. Full and half thorax deflections were computed from the chest band data. The cadaver test data was analyzed using ANOVA and logistic regression. The age of the subject at the time of death had influence on injury outcome while gender and mass of the subject had little or no influence on injury outcome.

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 describes the development and experimental validation of a Plug-in Hybrid Electric Vehicle (PHEV) dynamic simulator that enables development, testing, and calibration of a traction control strategy. EcoCAR 2 is a three-year competition between fifteen North American universities, sponsored by the Department of Energy and General Motors that challenges students to redesign a Chevrolet Malibu to have increased fuel economy and decreased emissions while maintaining safety, performance, and consumer acceptability. The dynamic model is developed specifically for the Ohio State University EcoCAR 2 Team vehicle with a series-parallel PHEV architecture. This architecture features, in the front of the vehicle, an ICE separated from an automated manual transmission with a clutch as well as an electric machine coupled via a belt directly to the input of the transmission. The rear powertrain features another electric machine coupled to a fixed ratio gearbox connected to the wheels.

A new biofidelity assessment system is being developed and applied to three side impact dummies: the WorldSID-α, the ES-2 and the SID-HIII. This system quantifies (1) the ability of a dummy to load a vehicle as a cadaver does, “External Biofidelity,” and (2) the ability of a dummy to replicate those cadaver responses that best predict injury potential, “Internal Biofidelity.” The ranking system uses cadaver and dummy responses from head drop tests, thorax and shoulder pendulum tests, and whole body sled tests. Each test condition is assigned a weight factor based on the number of human subjects tested to form the biomechanical response corridor and how well the biofidelity tests represent FMVSS 214, side NCAP (SNCAP) and FMVSS 201 Pole crash environments.

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.

For some vehicle dynamics applications, an estimate of a vehicle's center of gravity (cg) height and mass moments of inertia can suffice. For other applications, such as vehicle models and simulations used for vehicle development, these values should be as accurate as possible. This paper presents several topics related to inertial parameter estimation and measurement. The first is a simple but reliable method of estimating vehicle mass moment of inertia values from data such as the center of gravity height, roof height, track width, and other easily measurable values of any light road vehicle. The second is an error analysis showing the effect, during a simple static cg height test, of vehicle motion (relative to the support system) on the vehicle's calculated cg height. A method of accounting for this motion is presented. Similarly, the effects of vehicle motion are analyzed for subsequent mass moment of inertia tests.

The National Highway Traffic Safety Administration (NHTSA) has developed its Light Vehicle Antilock Brake Systems (ABS) Research Program in an effort to determine the cause (s) of the apparent increase in fatal single-vehicle run-off-road crashes as vehicles undergo a transition from conventional brakes to ABS. As part of this program, NHTSA conducted research examining driver crash avoidance behavior and the effects of ABS on drivers' ability to avoid a collision in a crash-imminent situation. The study described here was conducted on a test track under dry and wet pavement conditions to examine the effects of ABS versus conventional brakes, ABS brake pedal feedback level, and ABS instruction on driver behavior and crash avoidance performance. This study found that drivers do tend to brake and steer in realistic crash avoidance situations and that excessive steering can occur.

The National Highway Traffic Safety Administration (NHTSA) has developed its Light Vehicle Antilock Brake Systems (ABS) Research Program in an effort to determine the cause (s) of the apparent increase in fatal single-vehicle run-off-road crashes as vehicles undergo a transition from conventional brakes to ABS. As part of this program, NHTSA conducted research examining driver crash avoidance behavior and the effects of ABS on drivers’ ability to avoid a collision in a crash-imminent situation. The study described here was conducted on the Iowa Driving Simulator and examined the effects of ABS versus conventional brakes, speed limit, ABS instruction, and time-to-intersection (TTI) on driver behavior and crash avoidance performance. This study found that average, alert drivers do tend to brake and steer in realistic crash avoidance situations and that excessive steering can occur. However, this behavior did not result in a significant number of road departures.

Anthropomorphic test devices (ATDs) should accurately depict head kinematics in crash tests, and thoracic spine properties have been demonstrated to affect those kinematics. To investigate the relationships between thoracic spine system dynamics and upper thoracic kinematics in crash-level scenarios, three adult post-mortem human subjects (PMHS) were tested in both Isolated Segment Manipulation (ISM) and sled configurations. In frontal sled tests, the T6-T8 vertebrae of the PMHS were coupled through a novel fixation technique to a rigid seat to directly measure thoracic spine loading. Mid-thoracic spine and belt loads along with head, spine, and pectoral girdle (PG) displacements were measured in 12 sled tests conducted with the three PMHS (3-pt lap-shoulder belted/unbelted at velocities from 3.8 - 7.0 m/s applied directly through T6-T8).

This paper describes the National Highway Traffic Safety Administration's (NHTSA) efforts to determine how different outrigger designs can affect J-Turn and Road Edge Recovery test maneuver outcome. Data were collected during tests performed with three different outrigger designs (made from aluminum, carbon fiber, and titanium) having different physical properties (geometry and weight). Four sport utility vehicles were tested: a 2001 Chevrolet Blazer, 2001 Toyota 4Runner, 2001 Ford Escape, and a 1999 Mercedes ML320. The 4Runner and ML320 were each equipped with electronic stability control, however the systems were disabled for the tests performed in this study. A detailed description of the testing performed and the results obtained are discussed. From the results, a comparison of how the three outrigger designs affected the test results is provided.