A system, mobile device, backend server, and RFID toll module work in cooperation to automatically pay vehicular tolls to a toll agency that operates toll stations along a roadways travelled by the user of the mobile device. Upon approaching a toll station the mobile device enables the RFID toll module. The toll reader at the toll station transmits a toll reader signal that is received by the RFID toll module, which responds by transmitting a unique identifier. The unique identifier is associated with the mobile device at a toll account maintained by a toll service backend server. Upon completion of a toll transaction, the RFID toll module indicates the transaction to the mobile device, which forwards toll transaction information to the toll service backend server for payment from the toll account to the toll agency.