If acquisition of measured position and time data (position/time) from a position detection unit fails, a "GPS OFF mode" is set, and the latest position and time data is stored as start data. Thereafter, when the position and time data is obtained successfully, and the operation is recovered from the "GPS OFF mode", the "GPS OFF mode" is cancelled. Also, the obtained position and time data (restoration data) is stored. Monitor data is formed from the start data and the restoration data. The monitor data is transmitted to a management center through road-vehicle communication. Also, history data of the position and time stored in the position detection unit during the "GPS OFF mode" is read. If the history data satisfies the toll charging condition, the toll charging data is formed and is transmitted to the management center.