text: Driveless cars require many sensors in order for the car to work and drive on its own. It seems cool but what will happen when one of those sensors stopped working and you didnt know? The sensors were placed every where in the car so therefore it can work properly. "Google's modified Toyota Prius uses position-estimating sensors on the left rear wheel, a rotating sensor on the roof, a video camera mounted near the rearview mirror, four automotive radar sensors, a GPS receiver, and an inertial motion sensor..." There is a lot of sensors installed inside the car but something can go very wrong if one of them stop working and the car crashes and injure somebody.