text: Also, anothyer reason is because after all those changes in the car, they still need the human to drive it. Mostly all the work that is done, it's done by the car. But when there is a problem with the traffic, there's an accident or something the car needs the human to drive to be safe. GM has developed driver's seats that vibrate when the vehicle is in danger of backing into an object. The Google car simply announces when the diver should be prepared to take over, There are some other options like flahing lights on the windshield and other heads-up displays.