A navigation system is provided where an error in the road data and an omission of the road data can be compensated for, and a vehicle control system is provided for using the navigation system. A yaw rate generation starting position, a yaw rate peak position and a yaw rate generation finishing position of a traveling vehicle are detected. The three positions determined are an inlet position, a central position and an outlet position of a curved road. If the three positions are offset to positions of nodes N2, N3 and N4 on the curved road stored in a map information storing means of the navigation system, the positions of the nodes N2, N3 and N4 are corrected so that they are matched with the three positions. It is determined based on the corrected road data whether it is possible for a subject vehicle to pass through a road ahead of the subject vehicle. When it is impossible for the subject vehicle to pass through the road, a warning to a driver or an automatic speed reduction is carried out.