Effects of vehicle interior geometry and anthropometric variables on automobile driving posture

The effects of vehicle package, seat, and anthropometric variables on postu re were studied in a laboratory vehicle mockup. Participants (68 men and wo men) selected their preferred driving postures in 18 combinations of seat h eight, fore-aft steering wheel position, and seat cushion angle. Two seats differing in stiffness and seat back contour were used in testing. Driving postures were recorded using a sonic digitizer to measure the 3D locations of body landmarks. All test variables had significant independent effects o n driving posture. Drivers were found to adapt to changes in the vehicle ge ometry primarily by changes in limb posture, whereas torso posture remained relatively constant. Stature accounts for most of the anthropometrically r elated variability in driving posture, and gender differences appear to be explained by body size variation. Large intersubject differences in torso p osture, which are fairly stable across different seat and package condition s, are not closely related to standard anthropometric measures. The finding s can be used to predict the effects of changes in vehicle and seat design on driving postures for populations with a wide range of anthropometric cha racteristics.