DETOUR RECOMMENDED AREA ESTIMATION SYSTEM, DETOUR RECOMMENDED AREA ESTIMATION PROGRAM, AND NAVIGATION DEVICE

A detour recommended area estimation system includes: a recording medium; and a control unit configured to collect probe information from a vehicle; acquire a travel-avoided direction based on the probe information when the vehicle made a detour, the travel-avoided direction being a direction in which the vehicle would have been traveled if the detour had not been made; estimate an area in which a direction dependence degree of the travel-avoided direction is less than a reference value as a detour recommended area, and record the detour recommended area in a recording medium.