Traffic information processing system, a server apparatus and a traffic information processing method

This traffic information processing system comprising: a vehicle-mounted device, mounted on a vehicle; a vehicle-vehicle device mounted several detection section, based on information received from the vehicle device, a vehicle mounted with a vehicle detection device in place of driving the plurality of divided regions and the number of mounted vehicles with on-board equipment of the vehicle-vehicle device that is not fitted into the as the area sample zone a portion of; the total number of vehicle detection section, the number of all the vehicle detected entering the sample region; vehicle ratio calculation unit calculates values ​​associated with the ratio of the number of the vehicle and detecting the number of the total number of all of the vehicle detected based on the vehicle portion of the vehicle mounted on-vehicle device detecting unit detects the number of units mounted in the vehicle device is obtained; and a vehicle Total estimation calculation unit, with on-board mounting device according to the vehicle entering the area and the number of the vehicle ratio calculation unit calculates the correlation value of the ratio, the total number of vehicles calculation regions.