This project quantified the anthropometry and positioning of pregnant drivers in the automotive environment. Testing was conducted in an adjustable laboratory seating buck that could be configured to represent different vehicle-package geometries with various belt anchorage locations. Twenty-two pregnant subjects, divided into five stature groups, were measured in the seating buck at 3, 5, 7, and 9 months of gestation. Subjects were tested in four of eight different vehicle-package/belt-anchorage configurations at each test session, and were permitted to adjust their seat fore/aft position, seatback angle, and steering-wheel angle to achieve a comfortable driving posture. The anthropometry data collected on this small sample showed that the size and external contours of the pregnant abdomen are relatively independent of maternal stature. In general, fore/aft seat position, steering-wheel angle, and seatback angle remained about the same throughout pregnancy for subjects in all stature groups. Abdomen-to-wheel clearances decreased with gestational age and were smaller at all gestational ages for shorter subjects. The uterus lies completely below the steering-wheel rim until the 5th month of pregnancy, and that the top quarter of the uterus lies above the steering-wheel rim by the 9th month. Lap-belt angles (relative to horizontal) decreased with gestational age, and were smaller for shorter subjects who sat further forward relative to the fixed anchor points. Data on lap-belt placement relative to the pelvis and uterus indicate that the potential for lap-belt loading of the uterus in a frontal crash exists, even with the lap belt properly positioned across the anterior superior iliac spines (ASIS). The shoulder belt crossed the sternum higher and crossed the clavicle more inboard in the later months of pregnancy. (Author/publisher)
Abstract