A Mayday contact address database (20) is connected to a navigation control (10). The Mayday contact address database (20) stores emergency contacts which shall be given an emergency report in what priority according to factors such expressway, ordinary road, human involved accident or damage only accident. Therefore, emergency reports can be made in an appropriate order according to the Mayday contact database (20). Transmission methods can be determined according to stored data. By transmitting a Mayday standby call from a two-way communications device (22) to a Mayday center (24), the Mayday center (24) presumes the occurrence of an emergency if no reset call has been received within a predetermined time.