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One element of primary interest in the analysis and reconstruction of vehicle collisions is an evaluation of impact severity. The severity of an impact is commonly quantified using vehicle closing speeds and/or velocity change (delta-V). One fundamental methodology available to determine the closing speed and corresponding velocity change is an analysis of the collision based on a combination of the principles of Conservation of Momentum and Conservation of Energy. A critical element of this method is an assessment of the amount of kinetic energy that is dissipated during plastic structural deformation (crush) of the involved vehicles. This crush energy assessment is typically based on an interpolation or an extrapolation of data collected during National Highway Traffic Safety Administration (NHTSA) sponsored crash testing at nominal speeds of 30 or 35 mph.

There is a paucity of data regarding the potential for pediatric cervical spine injury as a result of acceleration of the head with no direct impact during automotive crashes. Sled tests were conducted using a 3-year-old anthropomorphic test device (ATD) to investigate the effect of restraint type and crash severity on the risk of pediatric inertial neck injury. At higher crash severities, the ATD restrained by only the vehicle three-point restraints sustained higher peak neck tension, peak neck extension and flexion moments, neck injury criterion (Nij) values, peak head accelerations, and HIC values compared to using a forward-facing child restraint system (CRS). The injury assessment reference values (IARVs) for peak tension and Nij were exceeded in all 48 and 64 kph delta-V tests using any restraint type.

Properly restraining a child in an automotive seat may require the use of a weight- and size-appropriate Child Restraint System (CRS). Proper installation of the CRS is a critical part of protecting a child during a motor vehicle collision. During a collision, child occupants sometimes exert enough force on the restraint system to generate load marks on the CRS and the vehicle restraint system. These marks are often relied upon by investigators to determine if the child occupant was properly restrained at the time of the collision. This paper is an observational study of the load marks generated from sled testing that was conducted using Hybrid III 3-year-old and 6-year-old Anthropomorphic Test Devices (ATDs). Tests were conducted with various child restraint systems that were installed in accordance with the manufacturer's recommendations as well as installed improperly. Additional tests were conducted with the ATDs without the use of a CRS.