To reduce fatalities or serious injuries, the object of this study was to research skeletal alignment in an automotive seat and clarify the differentiation by the factors of age, gender and body type. Additionally, it was also to create human body models which represent individual differences by morphing the skeletal alignment of THUMS based on the analysis results, and consider the structure of seats to ensure occupant safety by using those human body models. Analysis on X‐ray data revealed that the alignment in seated posture is classified into the following two types: mild S‐shaped and Kyphosis, and tends to be influenced by body mass index. To analyse the effects on occupant kinematics, especially the region of the abdomen and lumbar, by the difference of skeletal alignment in frontal impact, multiple models were created by morphing the skeletal alignment of THUMS ver.4. Then, the occupant kinematics has been studied by using those HBMs, and the results indicated a significant difference especially in pelvic region. Considering from the aspect of occupant protection in accidents, it shows that it is important to maintain the correct driving position.
Keywords: BMI, individual difference, seated posture, skeletal alignment, pelvis