A multi-mode in-vehicle control unit (ICU) contains a plurality of modems. Each modem allows the multi-mode ICU to transmit vehicle data over a different kind of transmission network. Exemplary transmission networks include wireless data networks, cellular telephone networks and satellite networks. Vehicle data is collected. The multi-mode ICU selects one of the modems for transmission of vehicle data to a processing center. Priorities can be assigned to the transmission networks and or modems to control order the transmission network selection process.