The Volpe Center performed a comprehensive engineering analysis of Event Data Recorder(EDR) data supplied by NHTSA to assess its accuracy and usefulness in crash reconstruction and improvement of vehicle safety systems. The Volpe Center gathered and analyzed over 2,500 EDR files that have been downloaded from the National Automotive Sampling System's (NASS) Crashworthiness Data System (CDS), Special Crash Investigations (SCI), and Crash Injury Research & Engineering Network (CIREN) databases supplied by NHTSA. The analyses focused on EDR file format and potential improvements, assessment of crash types where EDR data exist, review of EDR data for accuracy and completeness, EDR data comparisons with existing crash data, review of pre-crash, crash, and post-crash data for usefulness in better understanding the crash reconstruction, identification of error sources, and determination of methods by which researchers could use the EDR data to improve their crash case information.