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High-intensity discharge (HID) headlamps are increasingly being employed in place of incandescent headlamps for automotive forward light systems. While the post-impact analysis of incandescent bulbs and filaments to determine the power state at impact is a mature field, there is little information currently available in the literature that can be used to determine if an HID headlamp was powered at the time of impact. HID headlamps differ significantly both in architecture and operation compared to incandescent headlamps; the light is produced by passing electrical current through a gas and generating a luminous arc, rather than by resistive heating of an incandescent filament. Though the filament examination techniques often used by accident investigators cannot be directly applied to HID lamps, the unique features of these lamps provide opportunities for new methods. This paper presents the results of stationary impact tests performed on a representative HID lamp.

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.

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.

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.

Previous studies have suggested injury assessment reference values (IARVs) for lower neck injury based on scaled upper neck values. This study developed independent flexion and extension IARVs for the lower neck by matching Anthropomorphic Test Device (ATD) data to impact-tested post-mortem human subjects (PMHSs) with mid- to low-cervical spine injuries. Pendulum and sled tests with Hybrid III midsize male and small female ATDs were run under conditions mimicking those of published PMHS torso drop-sled tests and other PMHS studies. Measurements included upper and lower neck forces and moments, head acceleration, head rotation rate, and head/neck angles for the pendulum tests. Rear impacts corresponding to rigid seatback tests without a head restraint produced lower neck extension moments that increased dramatically with test severity, as measured by increasing delta-V and/or decreasing pulse duration.