Patent ID: 7418338

Claim:
A route search server for performing road route searches, comprising: basic road network storage means for storing road network information; congestion information storage means for storing congestion information; congestion information processing means for generating congested road network descriptions with prescribed timing based on said road network information stored in said basic road network storage means and on congestion information stored in said congestion information storage means; historical congested road network description storage means for storing the latest congested road network description among said congested road network descriptions generated by said congestion information processing means; historical congested road network description storage means for storing past congested road network descriptions among said congested road network descriptions generated by said congestion information processing means; and, information provision processing means for generating route information by searching road routes from said congested road network descriptions stored by said congested road network description storage means or by said historical congested road network description storage means and from said road network information stored by said basic road network storage means based on route specification information, and providing the route information, wherein said route information includes time information indicating the time of generation of the route information, and, when said time information is included by said route specification information, said information provision processing means selects said congested road network description at the time indicated by said time information from said congested road network description storage means or from said historical congested road network description storage means, and performs a road route search from the selected congested road network description and from said road network information stored in said basic road network storage means.