Guidance information is significant to the driver during manual steering of a vehicle. With difficulty in perceiving the environment (e.g. in dense fog or white-out conditions), the driver may encounter problems of handling the vehicle safely. A supplementary guidance display, which includes the road information, the future vehicle position, and the current vehicle position, can provide the preview information to the driver. Two display laws for predicting the future position of the vehicle have been studied in previous research. The kinematic display law with simple formulation is suitable for low vehicle speeds, while the nonlinear gain-scheduled display law can be applied to a wide range of vehicle speeds. With the assistance of the lateral guidance system, the driver may act as a simple proportional controller to safely steer the vehicle. The results of closed-loop simulation show the advantage of the guidance display. The human-in-the-loop steering simulator is used to further validate the effectiveness of the lateral guidance system for driver assistance.