The objective of this study was to examine seatbelt–neck contact in pregnant women seated in the rear seat of a motor vehicle and to measure neck compression in these women during frontal vehicle collision sled tests. Late‐term pregnant Japanese volunteers sat in the left side of the rear seat of a typical mid‐size passenger sedan with their seatbelt fastened. The quantitative characteristics of their seated posture and seatbelt paths were measured. Next, sled tests were performed using a pregnant body dummy to simulate a full‐frontal rigid barrier impact at target velocities of 29 km/h and 48 km/h. The shoulder belt deviated to the right side and subsequently contacted the neck of the shorter women (mean height, 152.3 ± 3.0 cm). During the sled tests, the shoulder belt compressed and applied more than 12.8 MPa of pressure to the neck. Complex head movements consisting of flexion, lateral deviation, and clockwise rotation around the x‐axis were also observed.

The results of this study demonstrate that the shoulder belt of the seatbelt contacts the neck of shorter late‐term pregnant women and causes neck compression during frontal collisions. New rear seatbelt systems are needed to enhance passenger safety, particularly the safety of pregnant women.