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An analysis of peak lumbar load data collected from the existing peer-reviewed literature on rear impact crash tests was performed. Values for peak lumbar tension/compression, peak lumbar sagittal forces, and peak lumbar flexion/extension moments were aggregated from each study. The trends in the accumulated data were analyzed as functions of the changes in velocity (delta-Vs) measured during the crash tests. The data were further analyzed to identify differences in trends found across variations in the testing conditions used across studies. These testing conditions included type of anthropometric test device (ATD) used, type of ATD pelvis used, ATD seating position, production year of seat used, type of seat used, and type of seat restraint used.

This paper presents an analysis on the position of driver eye height as a function of their standing height, weight, biological sex, seat back angle and seat bottom angle. Typically, eye heights are estimated based on standing height, or measured from a rigid seated position with a vertical seat back. While reasonably close, these estimated eye heights are generally not correct for individuals seated in deformable vehicle seats with non-vertical seat back angles. Thus, these measurements tend to overestimate the participants eye height in more ecologically probable scenarios, such as driver eye height while operating a vehicle. In this study, eye measurements were taken from a standing position and while seated on a rigid surface and then compared to the same participant’s eye height measured while seated on six different representative vehicle seats with seat back angles of 20, 25, and 30 degrees respectively.

Automotive Event Data Recorders (EDRs) are often utilized to determine or validate the severity of vehicle collisions. Several studies have been conducted to determine the accuracy of the longitudinal change in velocity (ΔV) reported by vehicle EDRs. However, little has been published regarding the measurement of EDRs that are capable of reporting lateral ΔVs in low-speed collisions. In this study, two 2007 Toyota Camrys with 04EDR ECU Generation modules (GEN2) were each subjected to several vehicle-to-vehicle lateral impacts. The impact angles ranged from approximately 45 to 135 degrees and the stationary target vehicles were impacted at the frontal, central, and rear aspects of both the driver and passenger sides. The impact locations on the bullet vehicles were the front and rear bumpers and the impact speeds ranged from approximately 7.9 to 16.1 km/h.

Accurately quantifying the severity of minor vehicle-to-vehicle impacts has commonly been achieved by utilizing the Momentum Energy Restitution (MER) method. A review of the scientific literature revealed investigations assessing the efficacy of the MER method primarily for: 1) inline rear-end impacts, 2) offset rear-end impacts, and 3) side impacts configured with the bullet vehicle striking the target vehicle at an approximate 90° angle. To date, the utility of the MER method has not been thoroughly examined and readily published for quantifying oblique side impacts. The aim of the current study was to analyze the effectiveness of the MER method for predicting the severity of side impacts at varying angles. Data were collected over a series of 12 tests with bullet-to-target-vehicle contact angles ranging from approximately 45° to 315° with corresponding impact speeds of approximately 12.5 km/h (7.8 mph) to 16.1 km/h (10.0 mph).

New in this study is the mathematical formula for calculating energy dissipated due to sliding under the action of Coulomb kinetic friction in the context of Impulse Momentum Planar Collision (IMPC) with isotropic restitution. The surface sliding dissipated energy theorem established here is precisely consistent with the laws of physics underlying IMPC. A principal goal of distinguishing between surface sliding energy dissipation and energy dissipation due to vehicle crush is to improve the rational basis for use of crush energy analysis with IMPC. Also new in this study is a consistent interpretation of Newton's, Poisson's and Stronge's restitution hypotheses as they apply to IMPC with Coulomb kinetic friction. While this paper adds to the understanding of energy dissipation, the IMPC method presented here is not new.

Instrumented human subject and anthropomorphic test device (ATD) responses to low speed lateral impacts were investigated. A series of 12 lateral collisions at various impact angles were conducted, 6 near-side and 6 far-side, with each test using an ATD and one human subject. Two restrained female subjects were utilized, with one positioned in the driver seat and one in the left rear seat. Each subject was exposed to 3 near-side and 3 far-side impacts. The restrained ATD was utilized in both the driver and left rear seats, undergoing 3 near-side and 3 far-side impacts in each position. The vehicle center of gravity (CG) change in velocity (delta-V) ranged from 5.5 to 9.4 km/h (3.4 to 5.8 mph). Video analysis was used for quantification and comparison of the human and ATD motions and interactions with interior vehicle structures. Human head, thorax, and low back accelerations were analyzed. Peak human subject head resultant accelerations ranged from 0.9 to 36.8 g’s.

Accident reconstructionists will typically document scenes, evidence, vehicles or objects of interest by using 3-dimensional laser scanners. These techniques are well documented, utilized and can be extremely accurate. However, when the subject of documentation involves surfaces that include intricate, highly reflective, and/or complex geometry (motorcycles, wheelchairs, stairs, etc.) the commercially available laser scanners can produce obscuring dense stray and scattered points which results in point clouds that could require tedious manual registration and/or optimization. This paper compares a FARO Focus laser scanner, Pix4DMapper, and Agisoft’s Photoscan point cloud data to FARO ARM measurements of vehicles, other transportation devices and architectural features. It was shown that the Pix4DMapper and Agisoft’s Photoscan point cloud data resulted in detailed and accurate point cloud data compared to the FARO ARM measurements.

It is extremely important to accurately depict photographs or video taken of a scene at night, when attempting to show how the subject scene appeared. It is widely understood that digital image sensors cannot capture the large dynamic range that can be seen by the human eye. Furthermore, todays commercially available printers, computer monitors, TV’s or other displays cannot reproduce the dynamic range that is captured by the digital cameras. Therefore, care must be taken when presenting a photograph or video while attempting to accurately depict a subject scene. However, there are many parameters that can be altered, while taking a photograph or video, to make a subject scene either too bright or too dark. Similarly, adjustments can be made to a printer or display to make the image appear either too bright or too dark. There have been several published papers and studies dealing with how to properly capture and calibrate photographs and video of a subject scene at night.

Federal Motor Vehicle Safety Standard (FMVSS) No. 108 has minimum performance requirements for retroreflective tape at different entrance and observation angles. In the author's preliminary research, all DOT-C2 retroreflective tape on the market is advertised as meeting and exceeding FMVSS No. 108 requirements. The authors' literature review revealed that there have been no publications quantifying the performance of commercially available DOT-C2 retroreflective tape across a wide range of entrance and observation angles. Therefore, without additional study, an accident reconstruction expert cannot know exactly how a specific type of compliant tape may perform, beyond the minimum federal requirements. In an attempt to solve this issue, the authors have quantified the performance of different types of retroreflective tape with a retroreflectometer.

Accident reconstruction experts are often asked to evaluate the visibility and conspicuity of objects in the roadway. It is common for objects placed in or along the roadway, vehicles, and required by Federal Motor Vehicle Safety Standard (FMVSS) No. 108 for certain vehicles and trailers, to have red and white DOT-C2 retroreflective tape installed on several locations. Retroreflective tape is designed to reflect light back towards the light source at the same entrance angle. The authors' literature review revealed that there have been no publications quantifying the performance of commercially available DOT-C2 retroreflective tape with real world vehicles. Therefore, without additional study, an accident reconstruction expert cannot know exactly how a specific type of compliant tape would perform beyond the minimum federal requirements. In the current research, the performance of white and red DOT-C2 retroreflective tape is quantified.

Determination of vehicle speed at the time of impact is frequently an important factor in accident reconstruction. In many cases some evidence may indicate that the brake pedal of a striking vehicle was disengaged, and the vehicle was permitted to idle forward prior to impacting the target vehicle. This study was undertaken to analyze the kinematic response of various vehicles equipped with automatic transmissions while idling, with the transmissions in drive and the brake pedals disengaged. An array of sedans, SUV's and pickup trucks were tested under 3 roadway conditions (flat, medium slope and high slope). The vehicle responses are reported and mathematical relationships were developed to model the idle velocity profiles for flat and sloped roadway surfaces.

A study was conducted to assess the relative accuracy of two measurement techniques commonly used for vehicle measurements in damaged-based accident reconstruction. The traditional technique of hands-on measurement was compared with the use of photogrammetry for measurement of targeted damaged vehicles. Three undamaged vehicles were subjected to 4 impacts, resulting in 4 damaged areas (two front, one side and one rear). The study's intent was only to examine the accuracy of each measurement technique. The influence of other confounding independent variables such as selection of measurement location on the vehicle, reference line location, and definitions of what constitutes "damage," etc., were controlled for and minimized by using predefined measurement points on the vehicles and prescribed station lines. The points on each vehicle were measured using both techniques, and compared to baseline reference measurements obtained via a TOPCON GPT-7005i prismless imaging total station.

In accident reconstruction, parameters such as the struck vehicle change in speed and the closing speed can usually be determined by means of conservation of energy and conservation of momentum approaches. While others have considered limiting cases of the effects of mass and stiffness on vehicle speed change and closing speed calculations, the full spectrum of variations in vehicle stiffness and mass ratios have not been rigorously evaluated. This paper presents a discussion of the effects on the calculated vehicle speed change as a function of the variation of the mass and stiffness ratios. Closed form analytical solutions and graphical representations are derived and depicted for the situations in which the ratio of the barrier impact test masses equate to that of the ratio of the vehicle masses for the reconstructed situation in question and for the scenario in which they do not.

Vehicle change in velocity is recognized as one of the most influential parameters on occupant kinematics and injury potential in motor vehicle collisions. Basic engineering principals and some recent epidemiological research indicate the characteristics of the vehicle velocity change, such as the shape and duration of the acceleration vs. time pulse, may also be important. Automotive bumper designs could be enhanced by recognizing these characteristics to potentially influence occupant kinematics and Whiplash Associated Disorders (WAD) in low speed rear impacts. Low speed rear impacts were conducted with a Delta V of 11 km/h using the BioRID P3 anthropomorphic test device. Nominal pulse durations of 80, 100, 140 and 180 msec were tested by varying the dimensions of a foam interface between the impacting pendulum and the rear surface of the test vehicle.

A search of the automotive collision trauma literature reveals that over the last 35 years shows that there have been less than ten published Society of Automotive Engineers (SAE) articles describing the collision effects and resulting human occupant kinematics in low speed side impact collisions. The aim of this study was to quantify the occupant response for both male and female occupants for a battery of low-speed side impacts with various impact speeds and configurations. Eight volunteers were used in a series of twenty-five staged side impact collisions with impact speeds ranging from approximately 2 km/h to 10 km/h and impact configurations to the front, middle and rear side portions of the vehicle. A NHTSA FMVSS 301 moving barrier was used as the impacting vehicle. A stiff bumper was constructed to fit the front of the barrier and was attached at a normal passenger vehicle bumper height. Occupant and vehicle responses were monitored by accelerometers and high-speed video.

Accident reconstruction typically requires estimating the change of velocity (Delta-V) imparted to vehicles during collision. Estimating Delta-V commonly involves measuring or estimating the deformation of the vehicles involved in a collision. Material coefficients, which relate barrier equivalent velocity (BEV) to deformation for the two vehicles, are then interpolated or extrapolated from barrier crash test data. Finally, the Delta-V for each of the two vehicles is usually calculated using single-degree-of-freedom (SDOF) impact mechanics formulas. This paper presents a derivation of SDOF impact mechanics formulas applicable to one-dimensional vehicle collisions. The governing equations presented are new, more complete and more efficient than previously published efforts. In particular, Newton's third law of physics concerning collision force is proportionally expressed as the product of vehicle weight, crush progression behavior and BEV.

Interest in the mitigation of whiplash associated disorders (WAD) has increased in priority over the last 10 years, and an increasing number of human subject rear-end collision tests have been conducted to assist in the understanding of WAD. Traditionally this testing has examined the effects of variations in occupant characteristics (age, height, gender, etc.), seat characteristics (geometrical and constitutive), and impact severity. This data has resulted in advancements in the understanding of WAD and has provided occupant performance corridors at specific velocity changes, however no controlled study has examined the singular effect of incremental velocity change increases on occupant kinematics. Moreover, while vehicle velocity change is typically employed as a singular measure of impact severity, it is of interest to examine whether this or other impact-related parameters, such as energy or acceleration, are also correlated with occupant kinematics.