We investigated the influence of vehicle control (driver vs. passenger) on postural activity and motion sickness in the context of a console video game. Using a yoked control design, individuals participated as driver-passenger dyads. Within dyads, individuals participated alone, with Driver sessions being recorded and played back to corresponding Passengers. Passengers were more likely than Drivers to report motion sickness. During game exposure, Drivers tended to move more than passengers. Yet participants who later became motion sick moved differently than those who did not, with changes in movement variability of the head and torso. The results confirm that control of a simulated vehicle reduces the risk of motion sickness, and that postural instability precedes motion sickness. The results can be used to guide the design of driving simulations and video games.