Abstract: A system and method for restricting cell phone use while operating a vehicle. The operation and functionality of a subject mobile communication device (MCD) is restricted during operation of a subject vehicle. A control/monitor communication device (controller) installs a functionality restriction application (FRA) on the subject MCD and registers the MCD to a server. The registration process associates a specific vehicle and specific functionality restrictions with the subject MCD. The vehicle may be associated with the subject MCD via an on-board module (OBM) integrated with an on-board diagnostic device of the vehicle. When the vehicle is operational, the OBM transmits a signal to the server. The server accesses the registration information and transmits a signal to the associated MCD. The signal activates the FRA as well as communication functionality so that if the subject MCD is within a threshold distance of the OBM it is restricted as specified.