Information on side impact fatal accident cases has been extracted from the NHTSA's 1977 Fatal Accident Reporting System (FARS) files, combined with parallel information from the National Crash Severity Study (NCSS), and used to estimate the relative frequency of various kinds of side impact collisions.
The analysis has been restricted to passenger cars to estimate the number of fatalities, the total number of occupants in all towaway crashes, and the ratio of these two numbers. Data are shown for (1) right and left side impacts, (2) for vehicles impacted by other cars, by trucks, or by fixed objects, and (3) for drivers vs. other seated positions. About 60% of the side-impact fatalities in passenger cars in the U. S. occur as the result of the car being struck by a truck or striking a fixed object; most of the other 40% result from impact by another passenger car.
A principal purpose of this analysis was to assess the value of the FARS data in providing an understanding of a particular accident type, and the conclusion is drawn that FARS is useful now, and is likely to be more so in the future. Since it contains the census of fatal highway accidents in the U. S., conclusions drawn from this file are limited only by inaccuracies in the data and not by statistical sampling considerations.