Influence of Fixing Feet in Rear-End Crashes

Abstract

Considering occupants’ safety in highly automated vehicles (HAVs) is one of the future trends in mobility. Passengers will not deal with driving the car anymore, as a result of the automated driving system (ADS) application. Seat backs can be reclined by occupants during long trips to provide a comfortable posture. Vehicle collisions will still be possible, regardless of ADSs being used in HAVs, as many cars will still be driven manually. This study follows two objectives. The first is to seek the influence of restricting the body’s feet on a body’s kinematic. The second aim is to investigate and compare the model’s body part injury criteria for upright and reclined seating postures with and without feet fixation. Finite element simulations are performed with a 50th percentile Virthuman model placed on a deformable seat and fastened to the seat by a three-point belt. Outcomes show that, if a body is in an upright posture, fixing models’ feet to the interior causes most injury criteria of body parts to be improved and will lead to safer conditions in comparison with accidents in which the model’s feet are free to move. The exception is the model’s tibiae, whose injury criterion was worsened. On the other hand, if the model is in the reclined position, fixing the model’s feet could improve the neck, abdomen, and knee injury criteria. Meanwhile, femur and tibiae injury criteria noticeably worsen.