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Approximately 600,000 fatalities occur each year as a result of pedestrians being impacted by motor vehicles (World Bank, 2008). Previous studies (Heller et al., 2009) have utilized databases such as the National Inpatient Sample (NIS) to gain a more thorough understanding of the common injury patterns that occur in real-world traffic collisions involving pedestrians in the United States. The NIS contains records on five to eight million hospital stays annually and provides a wealth of information regarding injuries to hospitalized pedestrian casualties in the U.S. Because of the large number of applicable records in the NIS and the randomized sampling procedure, the data can be used to complete analyses that are not possible with smaller databases such as the Pedestrian Crash Data Study (PCDS), which is not intended to be statistically representative of pedestrian crashes in general.

Field accident data have demonstrated that occupant ejection during vehicle rollover is associated with a high risk of serious and fatal injury. Although it has been demonstrated that seat belt use is highly effective in preventing occupant ejections, it has been argued that occupant containment during rollover can be accomplished with the use of laminated side glazing. This study was conducted to evaluate the retention characteristics of production laminated side windows. The current vehicle fleet was surveyed for vehicles equipped with production laminated side glass. The survey examined relevant window system parameters including glass retention system, glass configuration, and window geometry. A representative subset of five front door systems from several manufacturers was chosen for further evaluation. In addition, one legacy rear door system with laminated glass was included for comparison.

A method of computing dynamic roof crush in rollover accidents has been proposed (Bidez, et al., 2005; Cochran et al., 2005). The method used data obtained from accelerometers mounted to the roof rails of sport utility vehicles, along with other measurements, to compute the instantaneous deformation of the roof rails during dolly rollover crash tests. We examined the feasibility and practicality of this methodology in three ways. First, the theoretical derivation was examined. Errors appeared to have been made in deriving and/or interpreting the equations used to compute instantaneous roof crush. Next, a three-dimensional dynamic rollover simulation program was run to produce ideal acceleration data (Yamaguchi et al., 2006, 2005). Using these data, the equations in original, uncorrected form predicted dynamic roof deformations when none existed. When the equations were corrected, the simulation data yielded proper roof positions and no roof deformations.

Full-scale vehicle crash testing is often used as an engineering tool to reproduce the dynamic conditions of real-world accidents. The complex and destructive nature of conducting these crash tests makes them very expensive. Often times engineering analysis requires multiple tests wherein occupant motion or vehicle component performance comparisons are made when subject to specific dynamic conditions. For these situations, sled testing becomes the preferred evaluation method. Sled testing allows engineers to reproduce the dynamic conditions of a full-scale crash test in a controlled environment at a fraction of the cost. A particular advantage of sled testing is that only a single vehicle is consumed. Typically the occupant compartment of the vehicle, referred to as a vehicle buck, is mounted to the test sled. The sled and buck can then be subjected to accelerations representative of a particular crash environment.

Objective: To provide an understanding of the scope of the major sources of vehicle fire data, the questions they were intended to answer, and how issues of definition, inclusion, and quality can affect the conclusions obtained. The National Highway Traffic Safety Administration's (NHTSA's) Fatality Analysis Reporting System (FARS), by definition, focuses on fatal accidents. NHTSA also maintains the National Automotive Sampling System (NASS) General Estimates System (GES).These systems capture data on roadway accidents that resulted in injury, fatality or property damage and which were reported to police. The GES system is based upon data recorded in the police accident report. In addition, some databases of police accident reports are publicly available. The U.S. Fire Administration's (USFA's) National Fire Incident Reporting System (NFIRS) is used by fire departments to document details about all types of fires.

Over half of the 1.2 million annual traffic fatalities worldwide are pedestrians struck by motor vehicles [ 1 ]. Medical databases, such as the National Inpatient Sample (NIS), have been utilized to ascertain injury patterns in the general population of injured pedestrians [ 2 - 3 ]. However, the authors are not aware of any studies investigating how factors, such as physical impairments, intoxication, and pre-existing medical implants (e.g. hip replacement, artificial knee, etc.) affect the prevalence of pedestrian accidents or injury outcomes. Five to eight million inpatient hospitalization records are included in the NIS annually, and this large sample size allows for analyses that are not possible with smaller data sets on pedestrian injuries. The current study utilizes the NIS to evaluate how several factors such as blindness, deafness, intoxication, and pre-existing medical implants affect injury patterns when compared to the general population of hospitalized pedestrians.

In this paper, a real-world accident that involved a tractor-semitrailer that lost its brakes on a steep downgrade is analyzed. The crash was caused by brake loss due to massive overheating caused by inoperative brakes, driving too fast for conditions, and driving in an improper gear. The effect on brake temperatures from prior uphill and downhill stretches encountered just before the crash is considered. The crash is analyzed using a Microsoft® Excel spreadsheet-based transient brake model for three sets of published brake temperature modeling methodologies and parameters: The Grade Severity Rating System developed by NHTSA (GSRS), a model developed by the University of Michigan Transportation Research Institute (UMTRI), and a model developed by Rudolf Limpert (Limpert). A fourth and different approach utilized a heavy truck simulation (HVE-SIMON™) with HVE Brake Designer®. The results of this analysis using the four models are compared.

Numerous studies have validated EDSMAC4 as an effective method of reconstructing automobile collisions; however, little has been done to investigate the effect of varying stiffness coefficients on the results of accident reconstruction and simulation analyses. When comparing simulations to staged collisions, the stiffness coefficients are frequently well defined; however, this is not always the case in real world accidents. Six vehicle-to-vehicle test impacts were modeled using EDSMAC4. Stiffness coefficients for the vehicles were obtained from test data of exemplar vehicles. After modeling the impacts with the base stiffness level, the stiffness coefficients were modified for both vehicles either plus (+) or minus (−) 25%. The impacts were re-run and the predicted vehicle damage (maximum crush and pattern), impact severity (Delta-V), peak acceleration, impact duration, post impact trajectory, and impact force was compared.

The mechanics of on-road, friction-induced rollovers were studied with the aid of a three-dimensional computer code specifically derived for this purpose. Motions of the wheels, vehicle body, occupant torso, and head were computed. Kane's method was utilized to develop the dynamic equations of motion in closed form. On-road rollover kinematics were compared to a dolly-type rollover at lesser initial speed, but generating a similar roll rotation rate. The simulated on-road rollover created a roof impact on the leading (driver's) side, while the dolly rollover simulation created a trailing-side roof impact. No head-to-roof contacts were predicted in either simulation. The first roof contact during the dolly-type roll generated greater neck loads in lateral bending than the on-road rollover. This work is considered to be the first step in developing a combined vehicle and occupant computational model for studying injury potential during rollovers.

Lateral head motions, torso motions, lateral neck bending angles, and electromyographic (EMG) activity patterns of five human volunteer passengers are compared to lateral motions of a Hybrid III ATD during right-left and left-right fishhook steering maneuvers leading to vehicular tip-up. While the ATD maintained relatively fixed lateral neck angles, live subjects leaned their heads slightly inward and actively utilized their neck musculature to stiffen their necks against the lateral inertial loads. Except for differences in neck lateral bending, the Hybrid III ATD reasonably reflects occupant kinematics during the pre-trip phase of on-road rollovers.

Engineering Dynamics Corporation (EDC) recently updated the Human, Vehicle, Environment (HVE) software program to enable modeling of passenger cars and light trucks towing trailers. This paper reports on a comparison between the HVE EDSMAC4 collision module of the 3-dimensional computer simulation program and instrumented crash tests, in which one vehicle in each test was a pickup truck pulling a trailer. Use of the EDSMAC4 trailer model was found to provide better correlation between the simulation and test damage profiles, rest positions, vehicle trajectories, velocities, and Delta-V. It was also determined that the NHTSA-derived stiffness coefficients are sensitive to the impact configuration and depending on the impact configuration, it may be necessary to refine the coefficients according to the configuration.

This paper describes an investigation that seeks to understand how rollovers occur in real-world crashes, both by studying real world crashes and by analyzing vehicle handling tests to gain insights into potential mechanisms of pre-crash loss of control. In particular, this study focuses on one type of rollover, namely single-vehicle rollovers that follow a pattern of the vehicle first leaving the roadway and then returning to the roadway typically out-of-control. Aims of this study included the following: To describe the frequency and characteristics of single-vehicle rollovers involving an off-roadway excursion followed by a complete, if only temporary return to the roadway. To the extent possible, given available data, to assess the nature and consequences of driver inputs during the crash sequence. To define characteristics of crash scenarios which include a substantial proportion of this subset of single-vehicle rollovers.

The risk of sustaining injury in side collisions is correlated to collision severity as well as other factors such as restraint usage and occupant position relative to the impact. The most recent National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) data available (1997 to 2007) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) either between 8:00 and 10:00 or between 2:00 and 4:00, indicating a side impact collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on resultant delta-V, restraint system use, and occupant position relative to the impact.

The purpose of this study was to analyze real world crash data to determine whether airbags cause more severe injuries than they prevent and which types of injuries they cause. Using data from the National Accident Sampling System Crashworthiness Data System (NASS CDS), we examined passenger vehicles involved in frontal collisions for calendar years 1995-2003. We found that 99% of airbag-induced injuries to front outboard occupants are minor or moderate, regardless of the occupants' belt use. Belted occupants are 4 times more likely to sustain an AIS3+ injury (serious, severe, critical, or maximum) from any injury source compared to occupants with an airbag-induced injury; the risk of AIS3+ injury from any source is even higher for unbelted occupants. The evidence suggests that airbags do indeed mitigate severe injury.

The risk of sustaining injury in frontal collisions is correlated to collision severity as well as other factors such as restraint usage and airbag deployment. Eleven years (1997 to 2007) of National Automotive Sampling System (NASS) data from the Crashworthiness Data System (CDS) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) between 11:00 and 1:00, indicating a frontal collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on factors such as delta-V, restraint system use, and airbag deployment. Each body region (head, face, spine, thorax, abdomen, upper extremity, and lower extremity) was considered separately.

Testing techniques for creating rollovers have been a subject of much study and discussion, although previous work has concentrated on creating a repeatable laboratory test for evaluating and comparing vehicle designs. The two testing methodologies presented here address creating rollover tests that closely mimic a specific accident scenario, and are useful in accident reconstruction and evaluation of vehicle performance in specific situations. In order to be able to recreate accidents on off-road terrain, a test fixture called the Roller Coaster Dolly (RCD) was developed. With the RCD a vehicle can be released at speed onto flat or sloping terrain with any desired initial roll, pitch and yaw angle. This can be used to create rollover collisions from the trip stage on, including scenarios such as furrow trip on an inclined road edge.

Vehicle aspect ratio has been reported as a significant factor influencing the likelihood of fatality or severe injury/fatality during single-vehicle rollover crashes. To investigate this, dynamic simulations of friction-induced rollover accidents were performed using different roof heights, but otherwise identical vehicle parameters and initial conditions. Higher aspect ratios tended to cause the leading side roof to impact first, with significant impact force. The roof impact forces during the first roll of higher-roofed vehicles were primarily laterally directed with respect to the vehicle. Impact locations during subsequent rolls were less predictable. Lower aspect ratios produced higher impact forces on the trailing side roof that were more vertically oriented with respect to the vehicle. The vertically oriented forces potentially create greater risk for severe neck or head injuries.