Abstract
This paper examines a lateral-directional driver-support system that warns the driver of the lane departure by applying a torque variation to the steering as the vehicle approaches the lane boundary. A pulse-like torque variation is applied to the steering wheel so that the torque variation will have a minimum impact on the vehicle behavior, and yet serve as a warning to the driver. This pulse-like torque variation is designed to slightly move the steering in such direction that the vehicle will move back to the center of the lane, and it is also the information on the direction of the driver's corrective steering effort. With the driving simulator experiment and the road test, it has been made possible to effectively time the warning in order to minimize the lane departure and to prevent any distracting effect on the driving effort.