Abstract: In a steering angle correcting system, a steering amount required to maintain a positional relationship of a subject vehicle to a road lane ahead of the subject vehicle is calculated in a steering amount calculating device based on outputs from a first detecting device for detecting the state of a lane of a road ahead of the vehicle or which the vehicle is traveling, and a second detecting device for detecting a current positional relationship of the subject vehicle to the road lane. A steering device is driven by a driving device mounted between a grasping portion of a steering wheel and the steering device so as to decrease the difference between a steering amount detected by a steering amount detecting device and a steering amount calculated in the steering amount calculating device. Whenever a driver's intention and the determination by the system are different from each other, a driver can operate the steering wheel to intervene in the steering.

Abstract: An automatic travel guiding device is a combination of a navigation control unit and automatic travel control unit that judges the position of a vehicle on a travelling road on the basis of sensed circumstances of the road extending ahead of the vehicle and correcting a current position of the vehicle to a corresponding position on the road map. The device includes means for correcting road circumstances on the basis of road data read from map-information storage medium according to the current position of the vehicle to correlatively increase both the current position accuracy and the travel control accuracy according to travel guiding instruction for following a target course preset on a road map by sensing actual road conditions and to realize automatic travel control at an increased accuracy.