The purpose of this study was to evaluate the effectiveness of side door reinforcement beams in reducing occupant injury in side impacts and to determine whether cars fitted with 5 MPH energy absorbing bumpers, involved as the striking vehicle in side impacts, significantly affect the injury severity of occupants in the struck vehicle, particularly from the point of view of degrading any benefit obtained from the side door beam.

The results are based on analyses of Level 2 accident data collected from the eight county area surrounding Buffalo. The data set covers the period November 1969 to April 1975, a total of 34,253 accidents. In looking at the effect of door beams on occupant injury, the data have been filtered so that only accidents in which the struck vehicle suffered compartment damage were included.

The results of the study suggest that injury severity is reduced to some extent in vehicles equipped with side door beams but that the effect is small. For unrestrained occupants seated on the struck side, there was a significant side door beam benefit;​ for cars with side door beams, the proportion of no injuries was higher (65.1% vs. 60.4%) and the proportion of injuries of severity moderate or greater lower (9.3% vs. 13.0%). The effect was not as noticeable for restrained occupants. For occupants seated on the opposite side to that struck, door beams do not provide any significant benefit irrespective of restraint use. In terms of occupant protection, restraints offer significantly more benefit than side door beams.

Cars fitted with energy absorbing bumpers present a less aggressive striking vehicle but the effect is small. Energy absorbing bumpers do not appear to degrade the benefit obtained from side door beams.