Search Results

Injury to the far side occupant has been demonstrated as a significant portion of the total trauma in side impacts. The objective of the study was to determine the response of PMHS in far side impact configurations, with and without generic countermeasures, and compare responses to the WorldSID and THOR dummies. A far side impact buck was designed for a sled test system that included a center console and three-point belt system. The buck allowed for additional options of generic countermeasures including shoulder or thorax plates or an inboard shoulder belt. The entire buck could be mounted on the sled in either a 90-degree (3-o'clock PDOF) or a 60-degree (2-o'clock PDOF) orientation. A total of 18 tests on six PMHS were done to characterize the far side impact environment at both low (11 km/h) and high (30 km/h) velocities. WorldSID and THOR-NT tests were completed in the same configurations to conduct matched-pair comparisons.

This investigation addresses and evaluates: (1) belted drivers in frontal crashes; (2) crashes divided into low, medium, and high severity; (3) air-bag-equipped passenger vehicles separated into either model years 1985 - 1997 (with airbags) or model years 1998 - 2008; (4) rate of Harm as a function of crash severity and vehicle model year; and (5) injury patterns associated with injured body regions and the involved physical components, by vehicle model year. Comparisons are made between the injury patterns related to drivers seated in vehicles manufactured before 1998 and those manufactured 1998 or later. The purpose of this comparative analysis is to establish how driver injury patterns may have changed as a result of the introduction of more recent safety belt technology, advanced airbags, or structural changes.

The basis for this analysis was NASS/CDS 1997 to 2006. In the NASS database there were 60 cases with major fires in side impact crashes, 37 of which were in passenger vehicles less than 10 years old. These newer vehicles were examined in this study. Cases in NASS were examined to identify crash characteristics associated with major fires in side crashes. The database contained 22 cases with fatalities, eleven of which were coded as fire related. Three of these were associated with fires that did not originate from the crashed vehicle. The fuel tank was coded as the fire origin for 41% of the major fires in vehicles with side damage and for 7 out of the 8 vehicles with fire related fatalities. The most frequent crash characteristic was an impact with a narrow object that produced severe side damage. Lower extent of damage was evident in two fatal cases that involved a rollover following the side impact.

The basis for this analysis was FARS 1979 to 2005 and NASS/CDS 1997 to 2004. For these years, there were 12,493 cases in FARS where fire was coded as the most harmful event. In NASS there were 227 cases with major fires, 87 of which were in frontal crashes. The paper shows the annual trends in FARS with regard to overall fatalities and fatalities with fire as the most harmful event by direction of principal vehicle damage. The NASS/CDS files are used to determine the location of fire origin. The FARS data show that crashes with frontal damage are the most frequent crash types where fire is the most harmful event. In general, the most harmful event fire rates have declined with the overall fatality rates in FARS. However, in recent years the trend in fires with frontal damage has been on the increase. Cases in NASS were examined to identify patterns for major fires in frontal crashes. Engine compartment fires were by far the most frequent.

The National Highway Traffic Safety Administration has sponsored extensive research to improve the frontal protection of motor vehicles. Most of the research was conducted during the 1970's when belt usage rates were less than 10%. At that time, the research objectives did not anticipate the combination of air bags and three point manual belts as the restraint of choice for the 1990's. Consequently, little research was undertaken to extend the performance of this combination. However, the research conducted at that time offers opportunities for significant additional improvements in frontal protection. The purpose of this paper is to summarize some of the relevant research which was sponsored by NHTSA under the direction of the authors. Results will be highlighted which are particularly applicable to current vehicle configurations. Opportunities for further improvement, and required research are discussed.

The objective of the study was to document the thoracic deformation contours in a simulated frontal impact. Unembalmed human cadavers and the Hybrid III anthropomorphic manikins were tested. Data from the newly developed External Peripheral Instrument for Deformation Measurement (EPIDM) was used to derive deformation patterns at upper and lower thoracic levels. Deceleration sled tests were conducted on three-point belt restrained surrogates positioned in the driver's seat (no steering assembly) using a horizontal impact test sled at velocities of approximately 14.0 m/s. Lap and shoulder belt forces were recorded with seat belt transducers. The experimental protocol included a Hybrid III manikin experiment followed by the human cadaver test. Both surrogates were studied under similar input and instrumentation conditions, and identical data acquisition and analysis procedures were used. All six testedcadavers demonstrated multiple bilateral rib fractures.

A common injury type among foot and ankle injury is the Lisfranc trauma, or injury to the forefoot. The Lisfranc injury indicates abnormal alignment of the tarsal-metatarsal joints with the loss of their normal spatial relationships. In 2003, Smith completed a laboratory study of this injury mechanism at Wayne State University [1, 2]. He found Lisfranc trauma was correlated with impact force to the forefoot. He proposed a probability of injury function that is based on the applied force to the forefoot. This study examined the instrumentation in the foot of the dummies in the USA New Car Assessment Program (NCAP) and Insurance Institute of Highway Safety (IIHS) frontal crashes. Nineteen different passenger vehicles representing four different vehicle classes were selected based mostly on a large presence in the USA vehicle fleet. Both NCAP and IIHS crashed these nineteen makes and models.

The research reported in this paper is a follow-on to a five year research program conducted by General Motors in accordance with an administrative Settlement Agreement reached with the US Department of Transportation. This paper is the fourth in a series of technical papers intended to disseminate the results of the ongoing research [Digges 2004, 2005, 2006]. This paper summarizes progress in several of the projects to better understand the crash factors that are associated with crash induced fires. Part I of the paper presents the distribution of fire cases in NASS/CDS by damage severity and injury severity. It also examines the distributions by crash mode, fire origin, and fuel leakage location. The distributions of cases with fires and entrapment are also examined. Part II of the paper provides summaries of recent projects performed by MVFRI contractors. Technologies to reduce fuel leakage from siphoning and rollover are documented.

There is an increasing need to accurately define the soft tissue components of the human cervical spine in order to develop and exercise mathematical analogs such as the finite element model. Currently, a paucity of data exists in the literature and researchers have constantly underscored the need to obtain accurate data on cervical spine ligaments. Consequently, the objective of the study was to determine the geometrical and biomechanical properties of these ligaments from the axis to the first thoracic level. A total of thirty-three human cadavers were used in the study. Geometrical data included the length and cross-sectional area measurements; and the biomechanical properties included the force, deflection, stiffness, energy, stress, strain, and Young's modulus of elasticity data. Data were obtained for the following ligaments: anterior and posterior longitudinal ligaments, joint capsules, ligamentum flavum, and interspinous ligament.

With the widespread use of supplemental restraint systems (airbags), occasional rare injuries have occurred because of the force associated with these systems upon deployment. Recent case studies have demonstrated forearm fractures associated with airbag deployment. The present study was conducted to determine the tolerance of the human forearm under a dynamic bending mode. A total of 30 human cadaver forearm specimens were tested using three-point bending protocol to failure at 3.3 m/s and 7.6 m/s velocities. Results indicated significantly (p < 0.01) greater biomechanical parameters associated with males compared to females. The bending tolerance of the human forearm, however, was found to be most highly correlated to bone mineral density, bone area, and forearm mass. Thus, any occupant with lower bone mineral density and lower forearm geometry/mass is at higher risk. The mean failure bending moment for all specimens was 94 Nm.

This study assessed the primary involved physical components attributed to the head and face injuries of child occupants seated directly adjacent to the stuck side of a vehicle in a side impact collision. The findings presented in this study were based upon analysis of the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) for the years 1993–2007. Injury analysis was conducted for those nearside child occupants aged between 1–12 years-old. The involved children were classified as toddler-type, booster-type, or belted-type occupants. These classifications were based upon the recommended restraint system for the occupant. Injury mechanisms were assessed for the child occupants in each of the three groups. A detailed study of NASS/CDS cases was conducted to provide a greater understanding of the associated injury mechanisms.

The research reported in this paper is a follow-on to a five year research program conducted by General Motors in accordance with an administrative Settlement Agreement reached with the US Department of Transportation. In a subsequent Judicial Settlement, GM agreed fund more than $4.1 million in fire related research over the period 2001-2004. The purpose of this paper is to provide a public update report on the projects that have been funded under this latter research program, along with results to date. An analysis of FARS and State accident data has been completed. Results indicate that fire rates have been significantly reduced over the past 20 years. Fire rates for passenger cars and LTVs have approached similar levels. Fire rates by crash mode indicate that rear impact fires have been significantly reduced; however, fires in rollover crashes have seen considerably less reduction. The highest percentages of fires are subsequent to frontal impacts.

Real world crashes in NASS/CDS 1997 to 2000 were examined individually in order to find patterns in single vehicle rollover crashes. Typical maneuver induced rollovers of SUV's were reconstructed using the HVE model. From HVE and roll event reconstructions, the values of longitudinal, lateral, and vertical displacement, and roll, pitch, and yaw angle, for the pre-roll and rollover event were calculated. These values were used as inputs to a MADYMO model for simulated vehicle motion to predict occupant kinematics. Both near-side and far-side rollovers were simulated. The MADYMO model provided estimates of head velocity for the various rollover scenarios for a belted driver. In both near-side and far-side rollovers of the type reconstructed, the lateral component of head velocity was the greatest. Maximum head velocities of 5.3 m/s were predicted. The simulations were for two complete rollovers. The highest head velocity occurred during the first three quarter turns.

This paper presents an analysis of the National Automotive Sampling System (NASS) and the Fatal Accident Reporting Systems (FARS) data for the combined years 1988–97 with respect to side impacts. Accident variables, vehicle variables, occupant variables and their interactions have been considered, with special emphasis on occupant injury patterns. The crash modes considered are car-to-car, car-to-LTV (light trucks and vans) and car to narrow object, with special emphasis on the latter two. This study was undertaken to obtain a better understanding of injury patterns in lateral impacts, their associated causation factors, and to obtain information that will assist in prioritizing crash injury research problems in near side impacts. Of particular interest is the increase in the population of light trucks and vans and their influence on side impact priorities. Conclusions will be drawn regarding the frequency and injury severity of car-to-LTV’s and car to narrow objects.

Inertial loading of the head-neck complex occurs in rear impacts wherein the head and neck of the occupant are initially subjected to rearward forces. Epidemiological evidence exists to demonstrate the significance and societal impact of these injuries [4]. From a clinical perspective, trauma secondary to inertial loads belongs to the lower end of the Abbreviated Injury Scale, and no specific diagnostic techniques are available to quantitatively document the injury. Furthermore, identification of the mechanisms of injury and derivation of injury thresholds are limited. In fact, there is a paucity of literature focusing on the reproduction of rear impact-induced neck injuries due to a single-event rear impact. Because the impact acceleration is transmitted to the head from the torso via the cervical column, the components of the human neck play a role in the mechanics of trauma.

Since 1966 the federal government, through the National Highway Traffic Safety Administration, has promulgated regulations governing the crash safety of motor vehicles, with particular attention to passenger cars. However, during the next four years, most of the regulations will also apply to light trucks and vans. There are now 53 Federal Motor Vehicle Safety Standards (FMVSS). These standards primarily regulate the safety of new vehicles. For many disabled persons, especially those confined to wheelchairs, vehicles must be extensively modified to allow them to drive, or to ride as passengers. The objective of this paper is to examine the safety level intended to be afforded to able bodied persons by the crashworthiness FMVSS and to make observations on the special requirements of modified vehicles to afford the same level of safety to disabled persons. We will emphasize the safety needs of those who use vans since vans are the vehicles most extensively modified.

Spinal trauma produced from motor vehicle accidents, diving accidents, or falls occur at high rates of loading. This study was undertaken to reproduce clinically relevant cervical spine injuries under controlled conditions. Six isolated head - T2 human cadaveric preparations were tested using an electrohydraulic piston actuator at loading rates from 295 to 813 cm/sec. The Hybrid III head-neck was tested similarly at rates from 401 to 683 cm/sec. The input forces for specimen tests were of higher magnitude and shorter duration than the distally measured forces. In contrast, the Hybrid III head-neck revealed similar magnitude and duration force traces from input to output. The specimen preparations were analyzed kinematically at 1200 frames/sec with 20 to 30 retroreflective targets fixed to each level of the cervical spine. With this technique it is possible to temporally follow cervical damage as a function of applied force.

This paper uses the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) to estimate the population of front seat occupants exposed to far-side crashes and those with MAIS 3+ and fatal injuries. Countermeasures applicable to far-side planar crashes may also have benefits in some far-side rollovers. The near-side and far-side rollover populations with MAIS 3+ injuries and fatalities are also calculated and reported. Both restrained and unrestrained occupants are considered. Populations are subdivided according to ejection status – not ejected, full ejection, partial ejection and unknown ejection. Estimates are provided for the annual number of MAIS 3+ injuries and fatalities that occur each year in each category for the following belt use scenarios: (1) belt use as reported in NASS and (2) 100% belt use. In scenario 1, the exposure and casualties for the unbelted population are also shown. About 34% of the MAIS 3+F injuries in side crashes are in far-side crashes.

The objective of the present study was to determine the biomechanics of the human thorax in a simulated frontal impact. Fourteen unembalmed human cadavers were subjected to deceleration sled tests at velocities of nine or 13 m/s. Air bag - knee bolster, air bag - lap belt, and air bag - three-point belt restraint systems were used with the specimen positioned in the driver's seat. Two chest bands were used to derive the deformation patterns at the upper and lower thoracic levels. Lap and shoulder belt forces were recorded with seatbelt transducers. After the test, specimens were evaluated using palpation, radiography, and a detailed autopsy. Thoracic trauma was graded according to the Abbreviated Injury Scale based on autopsy findings. Peak thoracic deformations were normalized with respect to the initial chest depth to facilitate comparison between the specimens.

A multidisciplinary, automobile crash investigation team at the Jackson Memorial Hospital/Ryder Trauma Center in Miami, Florida, is conducting a detailed medical and engineering study. The focus is restrained (seatbelts and/or air bag) occupants involved in frontal crashes, who have also been severely injured. More than 60 crashes have been included in the study to date. Analysis of the initial data indicates that restraint systems are working to reduce many of the head and chest injuries which unrestrained occupants suffer. However, internal injuries among air bag-protected occupants may be unrecognized in the field providing new challenges in triage and injury diagnosis. In other cases, survival in extremely high severity crashes presents trauma management challenges due to the extent and complexity of the multiple injuries which result. The paper provides case examples to illustrate types of chest and abdominal injuries associated with air bag cases.