Real accidents were investigated, and a field study was conducted to investigate the sitting habits and attitudes of rear-seat passengers. In addition, the effectiveness of different protection systems was compared in a large number of numeric simulations.
The accident analyses showed that rear-seat passengers have only benefited to a limited extent from the improvements in passive safety in recent years and tend to suffer more serious injuries than the driver. The field study showed that around 29% of rear-seat passengers do not adopt the correct sitting position and that, due to discomfort caused by the seat belt, the belt is not used properly. A problem of comfort thus becomes a safety problem. The complex numeric simulations confirmed the picture that most current protection systems on rear seats are inadequate in serious accidents and that sitting positions other than the recommended one considerably worsen the injury situation for rear-seat passengers.
The use of a belt pretensioner combined with a belt force limiter can limit the forces to which car occupants are exposed to a biomechanically tolerable level. A belt force limiter with a stopper function can be a useful addition. An additional rear-seat airbag can prevent the passenger’s head from hitting the back of the front seat and thus further minimize the risk of injury. The decisive prerequisite for rear-seat safety, however, is the use of a seat belt. In addition to awareness-raising campaigns, relatively simple technical measures such as a seat-belt reminder can also help.