A method and system for determining a driver is provided. The method includes receiving and analyzing GPS data identifying locations of GPS enabled devices of a plurality of users. A group of users are determined to be located within a specified proximity to each other based on the analysis. The group of users are determined, based on an altitude, velocity, and a vector of the group of users, to be located within a vehicle. A position and role for each user with respect to the vehicle is determined. Selected functions of each GPS enabled device are controlled based on each role.