Abstract: A seat system for a vehicle includes a seat having a seat bottom on which a person can sit. An intermediate support structure is secured to the seat and the vehicle which allows the seat to rotate relative to the vehicle. An actuator can interact with the seat to cause the seat to rotate relative to the vehicle. One or more sensors can each measure an aspect of motion. A processor can (i) receive input from each of the one or more sensors, (ii) determine from this input a measure of rotation of the vehicle away from a nominal, level horizontal orientation, and (iii) utilize the input to determine a desired rotation of the seat. An angle that the seat has been rotated away from a nominal, level orientation is more than insubstantially larger than an angle that the vehicle has rotated away from a nominal, level horizontal orientation.