Radars, Cameras, and Lidar: How Self-Driving Cars See the Road

WIRED 

Q: How Do Self-Driving Cars See? You head into a left turn, and before you change lanes, you crane your head around for a quick look back. That's when you see it. Chugging along behind you, in that left lane you're aiming to call your own. Your pressing question--Does it see me?--is answered when the vehicle slows down, giving you plenty of space.