Mizuno 1 EFFECTIVENESS OF SEATBELT FOR REAR SEAT OCCUPANTS IN FRONTAL CRASHES

Recently, the general public in Japan is attaching increasing importance to the wearing of seatbelts by rear seat occupants. Some projects have been launched to have more rear seat occupants wear seatbelts in Japan. The National Agency for Automobile Safety and Victim's Aid (NASVA), for example, conducted a research project to evaluate the effectiveness of wearing a seatbelt based on crash tests. Full-width rigid barrier tests were conducted using Hybrid III AF05 and 3YO dummies in belted or unbelted conditions in the rear seat. This paper summarizes the analyses of crash tests in this project. For the belted AF05 and 3YO in the rear seat, the injury criteria were relatively low since contact with the car interior was prevented by a seatbelt, though the chest deflection of AF05 was large by the shoulder belt. However, when the AF05 was not belted, the knees and the head made contact with the seatback of the front seat and the head of the front seat dummy, respectively. The injury criteria were extremely high and exceeded the injury assessment reference values (IARVs). Due to this impact by the AF05, the injury criteria of the driver dummy became high. The unbelted Hybrid III 3YO was thrown around inside the passenger compartment, making contact at several locations. It was demonstrated that a seatbelt is useful for preventing hard contact with the vehicle interior. However, some challenges remain, one of which is that the loading by the conventional seatbelt is too large for the Hybrid III AF05 chest.