In this study, the level of protection offered to rear seat occupants in frontal crashes is investigated. The Fatality Analysis Reporting System (FARS) and National Automotive Sampling System Crashworthiness Data System (NASS CDS) databases were used for the analyses. The investigation focused on: 1- estimating the fatality protection effectiveness of the rear seat position relative to the right front seat position, using the double paired comparison method, 2- evaluating the effect of control group selection method on effectiveness predictions, and 3- identifying trends in rear seat occupant protection over model years of vehicles. By applying a uniform control group to the double paired comparison analysis of FARS data, this study suggests that all ages of occupants are safer in the rear seat than in the right front seat. Effectiveness estimates ranged from 5.9% to 82% for different age groups of occupants. Results indicate that although occupants overall benefit from sitting in the rear seat compared to the right front seat, for all model year vehicles, the protective effect of the rear seat relative to that of the right front seat has decreased in the newer model year vehicles. The reduction in the effectiveness was 43.7% for unbelted occupants and 33.5% for belted occupants. Logistic regression analysis on NASS CDS data shows that vehicle model year has a significant effect (p-value = 0.0043) on increasing the risk of injury for belted rear seat occupants. Considering these results, protection of rear seat occupants deserves more attention from the automotive industry and government agencies.
Keywords: Rear seat occupant; Effectiveness; Double paired comparison; Frontal crash; Control group; Model year