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This study presents a method to characterize the accuracy and precision of video-acceleration-position (VAP) devices, and presents results from testing of one such vehicle camera (“dashcam”) with global positioning system (GPS) used by taxi companies nationwide. Tests were performed in which vehicle kinematic data were recorded in a variety of real world conditions simultaneously by the VAP device, accelerometers, and a proven GPS-based speed sensing and data acquisition system. Data from the VAP device was compared to data collected by the reference instruments to assess timing, precision, and accuracy of reported parameters. Still images from the VAP video recording were compared with three dimensional laser scan data in order to analyze field of view. Several case studies are discussed, and some guidelines and cautions are provided for use of VAP data in accident reconstruction applications.

Previous studies into wheel or tire disablements have examined either the physical effects of loose lug nuts, or vehicle dynamics following a disablement. This study investigates driver perception of loose lug nuts on the left rear wheel of a sedan. Testing was conducted in which a 2002 Mercury Grand Marquis was driven at various speeds through a course which included several turns, with the lug nuts tight and loose. The vehicle was instrumented to record steering wheel acceleration, steering wheel angle, and seat cushion acceleration. The driver was videotaped from the vehicle interior and the vehicle and wheel motion was videotaped from the vehicle exterior. In the test with loose lug nuts the left rear wheel separated from the vehicle. The driver's subjective observations indicated that the condition of the loose left rear wheel was not perceivable prior to wheel loss. Physical evidence on the vehicle components and roadway is described.