PURPOSE: To provide a new display method for geographic area for issuing an alarm in an early stage relating to traffic information by a traffic center(TC).

CONSTITUTION: A large part of traffic obstructions is only local concerns, and in order to evade the transmission of the alarm in an early stage to the whole country, a digital cellular radio network is used and an early stage alarm is transmitted to a vehicle provided with a device matched with it. Since there is a case that the positions of the base stations of the network and the covering range are unclear in the TC, in the TC, the display of the geographic area to be supplied with the early stage alarm is transferred to the control computers C1 and C2 of the cellular network and the control computers C1 and C2 decide which base station supplies the combinational covering range most matched with the display of the geographic area and operate the transmitters BS1-BS3 and BS20 and 21 of the selected base station.