The recent advances in automated vehicle technologies are expected to contribute to driving safety by reducing human error. Especially in highly automated vehicles, the driver's role is emphasized because of the control mode transition between automated and manual driving. When the control mode changes from automated to manual mode, it is important that the driver is ready to regain control. In this context, we analyze the effect of driver's cognitive status on the transition of control authority from the viewpoint of workload and user experience. With cognitive simulations using biological cognition models,it is possible to determine the relationship between visual stimuli and motion response. From the results, we develop several claims for control-authority transition.