A Study of NMVCCS to Identify Critical Precrash Factors in Fatal Crashes

A National Highway Traffic Safety Administration (NHTSA) paper published in 2009, “Fatalities in Frontal Crashes Despite Seat Belts and Air Bags” found that around 40% of crashes in a study of National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) frontal fatal crashes with a belted occupant and frontal air bag were exceedingly severe. The paper concluded that once an occupant of a light vehicle is involved in a crash of this magnitude, chances for survival based on current crashworthiness practices are slim. Therefore, the most effective way to prevent fatalities of this type from occurring would be through avoiding or mitigating the severity of the crash. To expand upon that analysis, the intent of this study is to identify and prioritize the factors involved in fatal crashes and assess the potential effectiveness of emerging or existing technologies that may have prevented or lessened the severity of the crash. The study was conducted by a multidisciplinary team of NHTSA crash investigators, engineers and a statistician who analyzed real-world fatal crashes found in the National Motor Vehicle Crash Causation Survey (NMVCCS). NMVCCS was a nationally representative survey conducted by NHTSA from 2005-2007. Trained researchers conducted on-scene investigations on nearly 7,000 crashes during the project, focusing on the precrash phase of the crash. The ability to investigate the selected crashes on-scene, in most cases within minutes, allowed the researchers to make better assessments of the events that led up to the crash. The survey collected up to 300 data elements on the driver, vehicle, and environment. Important components of NMVCCS were based on a methodology originally outlined by Kenneth Perchonok, including coding of the critical event, critical reason, and the associated factors that were present at the time of the crash. During this study the NHTSA team conducted indepth clinical analysis of each of the fatal crashes collected in NMVCCS, assigning the critical and secondary factors that led to the crash. The team also identified potential crash prevention measures at the driver, vehicle, and environmental levels. The results indicate that crash avoidance technologies including lane departure warning/lane keeping, electronic stability control (ESC), alcohol detection, and auto/assisted braking could have been beneficial in preventing many of the fatalities.