Patent ID: 8185299

Claim:
A route search device comprising: a storage medium for storing traffic information classified by weather conditions; a pointing device which sets a starting point and a destination; and a guide route search module that searches routes having a shortest required travel time for a plurality of weather conditions from the starting point to the destination, calculates a plurality of required travel times for each of the weather conditions for each of the searched routes, and selects a route having the smallest amount of variation of the plurality of the required travel times from the searched routes as a guide route by using traffic information stored in the storage medium; wherein the traffic information stored in the storage medium includes travel time for each link comprising a road on a map under each weather condition, and wherein the guide route search module includes: a weather condition-based route search module that determines a shortest travel time route from the starting point to the destination under each weather condition by using the traffic information stored in the storage medium; a link series-identifying module that extracts link series which vary with weather conditions from link series comprising the shortest travel time route determined by the weather condition-based route search module, determines required travel time for each of the link series that vary with weather conditions by using the traffic information stored in the storage medium, and identifies a link series smallest in the amount of variation in the required travel time for the weather conditions in each of the link series; and a link series-registering medium for registering a link series identified by the link series-identifying module as a link series comprising the guide route from the starting point to the destination.