Elon Musk said a Tesla could drive itself across the country by 2018. One just crashed backing out of a garage.

When Mangesh Gururaj's wife left home to pick up their child from math lessons one Sunday earlier this month, she turned on her Tesla Model S and hit "Summon," a self-parking feature that the electric automaker has promoted as a central step toward driverless cars. But as the family's $65,000 sedan reversed itself out of the garage, Gururaj said, the car abruptly struck the garage's side wall, ripping its front end off with a loud crack. The maimed Tesla looked as if it would have kept driving, Gururaj said, if his wife hadn't hit the brakes. No one was hurt, but Gururaj was rattled: The car had failed disastrously, during the simplest of maneuvers, using one of the most basic features from the self-driving technology he and his family had trusted many times at higher speeds. "This is just a crash in the garage.