According to navigation systems and methods, when a detected current position has deviated from a guidance route, a navigation device transmits a reroute calculation condition to an information distribution center including the current position and the destination. Based on the reroute calculation condition, the information distribution center determines whether a distance from the current position to a closest adjacent link is equal to or shorter than a predetermined distance. When the distance from the current position to the closest adjacent link is longer than the predetermined distance, the information distribution center distributes to the navigation device reroute prohibition information including information regarding the adjacent link and a maximum waiting time. The maximum waiting time is a time that must elapse before the navigation device can again transmit the reroute calculation condition.