US Patent 7546203 Route searching device

A route searching apparatus comprises a processing device that searches a guided route along which a vehicle is to be guided from a current vehicle position to a destination and also searches a detour route for detouring a detour segment set over part of the guided route. The processing device extracts guidance-requiring intersections at which the vehicle needs to be guided to follow a course among intersections on the guided route, sets a segment ending at a guidance-requiring intersection close to the current vehicle position among the guidance-requiring intersections as the detour segment, and searches the detour route for detouring the detour segment.