A network device associates a fleet vehicle with a driver of it. The network device receives customer input associating a group of media access control (MAC) addresses of portable devices with driver identifiers and stores, in a memory, the MAC addresses associated with the driver identifiers. The network device also receives, from a vehicle telematics unit, a vehicle identifier of a vehicle connected to the vehicle telematics unit and a MAC address of a particular portable device proximate the vehicle. Based on the MAC address of the particular portable device, the network device associates a particular driver identifier and the vehicle identifier. The vehicle telematics unit may determine that driver is no longer driving when it can no longer detect a signal from the particular portable device that was proximate the vehicle.