Through the use of a video-based motion data collection system the effects of seat and package factors on subject selected posture were examined for four automotive seats. Subjects were placed in both sedan and van interior packages with respect to seat height and toebar to steering wheel depth. The seats were adjusted to both the lumbar on and off positions with the test subjects allowed to choose their own fore/aft seat position and backrest recline. Subjects were not instructed on placement of the pelvis in the seat. Several internal joint locations of the spine were estimated to examine the overall spinal position and its relation to the position and contour of the seat. Results indicated that occupants did not use the lumbar supports as they were intended, and instead slid forward in the seats, away from the lumbar supports. Subjects chose more erect postures when the seats were in the higher van setting. Postural changes from the driver to passenger position affected the angle of the knees, with some differences reaching up to the hips. These findings can be combined with seat factors to determine correlations between SAE manikin and human responses.