1. A navigation system, comprising: a memory that stores traffic information; and a controller that: creates prediction traffic information based on the traffic information stored in the memory; searches a plurality of routes to a destination, each route including at least one link; calculates a predicted passage time of each link in each route; obtains, for each link, prediction traffic information at the predicted passage time, based on the created prediction traffic information; and extracts the obtained prediction traffic information pertinent to route searching as information to be distributed, according to a predetermined order of priority.