One aspect of the disclosure provides a control device that is located inside the passenger compartment of a vehicle. The control device may include a portable computing device configured to execute software that effectively enables passengers to use a touch screen (or another input device) to perform control actions for the vehicle that would otherwise take a flip of a switch, turning of a knob, or pressing of a pedal. For example, the portable computing device may be used to steer the vehicle or apply the brakes of the vehicle. The capabilities of the portable computing device are subject to location-specific permissions. The portable computing device, for example, may be allowed to steer the vehicle only when it is located in the area of the vehicle's driver seat.