How humans will compliment AI to increase safety of autonomous cars

Testing and trial runs of autonomous cars are going on briskly so that they can hit the roads soon, commute from one place to another and ridesharing companies can use them to ferry passengers to their destination. Autonomous cars would alter the long-established relationship between the driver and the car, as the vehicle steers, stops, accelerates, turns, identifies hurdles on its own and avoids collisions. This would be reinventing the car industry and its implications for the future would be colossal. But would autonomous cars make all forms of human intervention a thing of the past completely and at any stage there would be no need of human direction? What would happen in rarer scenarios where the car may need an external control for better navigation?