National Crash Severity Study Quality Control Task V Analysis To Refine Spinout Aspects Of Crash Final Report PDF Download

This study investigates the fatalities on the National Crash Severity Study (NCSS) of towaway, passenger car accidents. The analysis is in three stages. First, NCSS fatalities are compared to the fatally-injured occupants reported on the Fatal Accident Reporting System (FARS), as a tool for evaluating the representativeness of the NCSS data. Second, estimates of the probability of fatality for NCSS are computed for various conditions, such as the incidence of fire and the sex of the occupant. Third, in cases where two factors are highly correlated, such as is the case for rollover and ejection, modeling techniques are used to help quantify the effects of each variable. The results of this study suggest the following preliminary conclusions: (1) FARS and NCSS have similar distributions of many variables. These include urbanization, size of vehicles, type damage to vehicle, occupant seating location, sex, and restraint use. Differences resulting from the investigative methods and geographical areas of the two studies are identified and assessed. (2) On the NCSS file, many variables are associated with a much higher rate of fatality. These include (a) at the accident level: the number of vehicles involved, urbanization, and the incidence of fire or explosion; (b) at the vehicle level: the change of velocity at impact, the direction of the impacting force, and vehicle damage area; and (c) at the occupant level: seating position, age, sex, ejection, entrapment, and restraint use. (3) Rollover and ejection, which often occur together, are each independently associated with a higher rate of fatality. Of the two factors, ejection appears more related to a higher probability of fatality than does rollover alone. NCSS is the best currently-available source of accident data for analyzing injury-related factors. This report attempts to describe the accidents occurring in the NCSS sampling areas, and suggest ideas for further research.