Effectiveness of the Load Legs in Enhancing the Passive Safety of Rear-Facing Child Seats in Frontal Crash 2024-26-0343

The passive safety performance of a child seat is modulated by the design features of the child seat and the vehicle interior. For example, in the rear-facing configuration, the child seat impacting front structures increases the head injury risk during a frontal crash. Therefore, this study evaluates the effectiveness of the load leg countermeasure in improving the child seat's overall kinematics and its capability to prevent the secondary impact on the vehicle interior structure in a severe frontal crash scenario. An in-depth, real-world crash investigation involving a properly installed rear-facing child seat impacting the center console was selected for the study where the infant sustained a severe brain injury. In addition, this crash is employed to choose the crash parameters for evaluating the effectiveness of the load leg countermeasure in a similar scenario.

Finally, crash sled tests are conducted using the crash signature of the vehicle as obtained from the NHTSA NCAP rigid barrier test that matched the severity of the actual crash. With and without load-leg conditions are compared.

The overall kinematics improved with the load leg and prevented the blunt impact between the child seat and the front console and seats. As a result, the Head Injury Criteria were measured below the published IARV compared to the scenario with no load leg. Furthermore, the head injury criteria without the load leg were 123 % higher.

The load leg countermeasure provides an additional load path that improves the overall performance of the rear-facing child seat by keeping it more stable during the crash. Furthermore, the vehicle floor structure provided the required reaction load without damaging or buckling the vehicle floor. This study is limited to the frontal crash scenario without any significant obliquity of the impact.