A vehicle control system controls vehicle speed and provides a warning by deciding whether or not the prevailing vehicle speed allows the vehicle to pass a curve in the road ahead in accordance with the surrounding environment of the vehicle. The system calculates a gaze angle, .theta. which is made between a direction a of a vehicle in its actual position P.sub.0 and a segment b joining the actual position P.sub.0 and a prospective position P.sub.n. The vehicle speed control or warning is performed when the gaze angle .theta. exceeds a reference gaze angle. This reference gaze angle varies with the angle of view of the driver. At high-speed travel or at night where the drivers visibility angle is reduced, the reference gaze angle is set to a small value so that the vehicle control may be advanced. At low-speed travel or in the daytime where the driver's visibility angle is increased, the reference gaze angle is set to a large value so that the vehicle control may be delayed.