According to the automobile industry has been developing day by day, traffic accidents are increasing and the rear-end collision is the second largest of the entire collision. Due to the high social cost caused by rear-end collision, several studies are in progress at home and abroad. Previous studies have shown that neck injury caused by rear-end collisions can be prevented by seat conditions. In this study, to find the condition that reduces neck injury, change of neck injury in rear-end collision is analyzed according to headrest height, seatback angle, and seatback torque using BioRID II dummy model and passenger behavior analysis program MADYMO. Therefore, it is expected that the condition of each variable to reduce the risk of injury to the neck can be applied to the seat design, which will reduce the injury and the social cost caused by the rear-end collision.

IIWPG protocol for the dynamic testing of motor vehicle seats is a test procedure for ratings of seats and head restraints for neck injury prevention in low speed rear impacts. In this study, we evaluates the performance of the car seat in the dynamic test was enacted by IIWPG and initial geometry test that has been enacted by RCAR to vehicle being sold in the market today. 6 models became the A and G in the final rating that reflects the results of the dynamic test and Initial geometry test. Electronic active head restraint was found to be allowed to operate quickly headrest, it is very effective in the prevention of neck injury in support of the head of the passenger. we suspects that this is contributed lower the value injuries reduce the relative acceleration between the chest and head. It is determined that the expanded application is required up to the small car because rating appears high in the vehicle equipped with the electric active head restraint. In addition to the evaluation of the impact velocity and collision direction, neck injury continued research to present proposals for improvement is required future.

The neck injury occupies the most of injury that happened by the rear impact car accident. This study was analyzed about influence of the neck injury in low speed rear impact and car crash accident investigation. There is no neck injury in low speed side rear impact. On the other hand, there is initial neck injury symptom of 10 % but no long-term neck injury symptom in low speed offset rear impact. It appeared that the possibility of neck injury in low speed rear impact is low. For the more study about the neck injury, it should be evaluate the effects of the car body structure, frame structure and rear crash pattern.

This study was analyzed about influence of the seat back strength on neck injury in low speed rear offset impacts. MADYMO human model with the detailed neck model was used to define the magnitude and direction of internal forces acting on the cervical spine during rear impact. The analysis of neck motion and soft tissue neck injury(STNI) were studied using the lumped parameter model. Increased strength of the seat back resulted in increased ligament and disc forces. On the other hand, decreased strength of the seat back resulted increased force. It is clear that an appropriate strength of seat back allows to minimize a neck injury.