A traffic information system including a travel history database retaining the data on the travel history of vehicle measured at a constant temporal or running interval; a link cost weighting pattern database for storing patterns for weighting the link costs of road links, used in the determination of the travel paths of vehicles; a vehicle ID/link cost weighting pattern set database retaining the data representing the matching of the vehicle IDs with their associated link cost weighting patterns used to determine the travel paths of the vehicles; a link cost weighting pattern selection unit selecting the patterns for weighting the link costs used to determine the travel paths of the vehicles on the basis of the vehicle IDs; and a vehicle ID/link cost weighting pattern matching unit recording the data representing the matching of the vehicle IDs with their associated link cost weighting patterns.