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The use of Heavy Vehicle Event Data Recorders (HVEDRs) in collision analysis has been well recognized in past research. Numerous publications have been presented illustrating data accuracy both in normal operating conditions as well as under emergency braking conditions. These data recording devices are generally incorporated into Electronic Control Modules (ECMs) for engines or Electronic Control Units (ECUs) for other vehicular components such as the Anti-Lock Brake System. Other research has looked at after-market recorders, including publically-available Global Positioning System (GPS) devices and fleet management tools such as Qualcomm. In 2009, the National Fire Protection Association (NFPA) incorporated a Vehicle Data Recorder (VDR) component into their Standard for Automotive Fire Apparatus. The purpose of this was to “…capture data that can be used to promote safe driving and riding practices.” The Standard requires minimum data elements, recording times, and sample rates.

Often an accident reconstructionist is asked to determine vehicle speeds where the vehicle impacts a roadside object. One class of roadside objects that can be involved in the impact are the end treatment energy absorbing systems of “Jersey” barriers, guard rails and bridges. One such end treatment system is known as the Guard Rail Energy Absorbing Terminal, G-R-E-A-T. The G-R-E-A-T system consists of 6 to 8 foam and metal honeycomb cartridges surrounded by a framework of triple-corrugated steel guardrail. The number of cartridges used determine the maximum impact speed the barrier will safely handle. This type of accident cannot be analyzed as a fixed barrier impact. A method has been developed to determine the impact speed of a vehicle that has hit a constant force ( constant deceleration ) energy absorbing end treatment system.