The present invention relates to a method and apparatus for sensor synthesis and arbitration between mobile devices and vehicles, and specifically relates to a system and method for using data that is external to a vehicle in vehicular applications. The system and method include determining data that is external to the vehicle is available for use, comparing the external data to data that is available from a vehicle system, and determining whether the external data has a higher utility function compared to data that is available from a vehicle system. The system and method further include using the external data to enhance a vehicular application if the external data has a higher utility function.