FOX 26 - Your phone could soon be your car key. Volvo is experimenting with letting drivers use a smartphone app instead of a car key to start their cars. You don't even have to have your phone in your hand to start the engine. Proximity sensors can detect when the phone is “near” the car and allow the doors to open and the engine to start. The so-called digital technology will be available next year in Sweden then it'll make it's way to the U.S.