Tesla's self-parking Summon feature is getting an upgrade, and it'll be ready in less than six weeks. In a series of tweets, chief executive Elon Musk revealed that the beefed-up feature will now allow vehicles to drive around parking lots, find empty spots and read parking signs. "Car will drive to your phone location & follow you like a pet if you hold down summon button on Tesla app," he wrote, without giving any further details.