Yeah when you put it that way, your position makes a lot of sense. Thanks for sharing. I think the disconnect is that I see that sensor as hugely important.

Yeah when you put it that way, your position makes a lot of sense. Thanks for sharing. I think the disconnect is that I see that sensor as hugely important. If you were in a car and it lost the ability to sense speed via the speedometer, how would it pull over and stop? How would it know how quickly to steer towards the shoulder? How would it know when it had stopped? When airline autopilots were developed you didn't have a dozen ways to sense speed. With a car you have the speedometer, GPS, probably some kind of estimates from LIDAR and vision, and the ability to integrate output from the accelerometers and feed all those into a kalman filter to make a really good model for the car's speed even if the more accurate methods fail. Certainly there are good odds it could perform well enough to move the car to the shoulder. I guess I am less worried about those kinds of more minor failures and more worried about the kinds where humans are suddenly thrust back into the loop. On airplanes the pilots nearly always have a way to control the plane and plenty of time to react since they've got 5-30 minutes worth of glide. In a car when something goes wrong you might well have vehicles on either side, in front and behind if it's heavy traffic. And in that case if the car finds itself asking for a human driver very suddenly who has to start making very good decisions faster than a human is capable of. In my mind the "you can always pull over and stop" only works if you're assuming that the car is driving on an immaculately paved stretch of nearly or completely empty road.