Reclined postures in vehicle seats: Preferred seatback contours and head support locations

Reclined postures in vehicle seats have received increasing attention due to vehicle automation, but research using current seats may not be applicable. Furthermore, published recommendations for longitudinal seat back contour in automotive seats are difficult to apply to seat design due to insufficient information concerning reference points and contours. To address these gaps, a laboratory study was conducted with a specially constructed seat with a seat back pivot coincident with the seat H-point. Thirty men and women adjusted the seatback longitudinal to their preference at varying reclined angles and three different starting contours. Preferred head support locations were measured in each condition. The participants’ selected seat back contours were strongly influenced by the starting contour but were unrelated to seat back angle and to participant characteristics. Bézier parameters were used to estimate the range of contours that would be needed to accommodate the preferences of a large percentage of sitters.