1. A vehicle safety system operating on a driver's cellphone and comprising: selective blocking apparatus, controlled by a processor, for blocking specified functionalities of the cellphone only when the cellphone is in a vehicle in motion; and communication functionality operative to receive from a remote server and deliver updates which determine which specified functionalities the selective blocking apparatus is to block wherein the processor is configured to include cellphone identification functionality operative to identify presence of a cellphone in a driver's seat area by receiving and analyzing RF signals of the cellphone's modem and accordingly, to command the selective blocking apparatus to block specified functionalities of only the driver's cellphone without affecting functioning of other cellphones present in the vehicle the system also comprising plural sensors deployed in plural vehicle locations and wherein at least one of said sensors comprises an antenna and Analog-to-Digital Converter (ADC) and wherein the cell identification functionality includes a signal processing component to which sensor samples are transferred and which, responsively, is operative to determine whether or not the mobile phone is located in the vehicle's driver's vicinity wherein said signal processing component performs, for each new suspected signal: a. detection of the new suspected signal at at least one sensor/s deployed in the vehicle, at at least one bands; b. computation of a received power level parameter characterizing the new suspected signal from all of the sensors; c. computing estimated number of signal sources inside the vehicle; and d. computing estimated location of each signal source, and wherein said computing of estimated signal source location is learning-based.