Abstract: A navigation server capable of guiding a mobile subject such as an automobile by a navigation device, while appropriately evaluating the level of safeness of individual link in a disaster occurring area in consideration of the actual disaster condition is provided. According to the navigation server of the present invention, the links included in the disaster occurring area are extracted, and the cost of each of the extracted links is evaluated on the basis of the probe information. There is high probability that the spatial and temporal moving pattern of the automobile (a first mobile subject) represented by the probe information reflects the influence of the disaster. Therefore, the level of the safeness of individual link included in the disaster occurring area may be evaluated as the cost of individual link accurately in consideration of the actual disaster condition and road condition.

Abstract: A navigation server for assisting guidance of moving objects such as automobiles by a navigation device while considering the level of safety of each link in the area where a disaster has occurred and adequately evaluating the safety in consideration of the actual disaster situation. A navigation service extracts links included in a disaster area and evaluates the cost of each of the extracted links according to probe information. The probability of reflection of the adverse influence of the disaster on spatial and temporal movement patterns of an automobile represented by the probe information is high. Therefore, the level of safety of each link in the disaster area can be adequately evaluated so that the adverse influence of the disaster can be avoided.