Earlier quoted context omitted.
So it's all fine when a lorry rear ends and pancakes a car because the driver fell asleep?
No, but at least from the PoV of public perception the situation is easier to deal with in a way that allays fear. In your example that one drive is taken off the road. That drive is not a problem, and people assume that the remaining drivers are, for the most part, fine and unlikely to make the same mistake. In the automated truck example you can't take that one driver off the road because barring equipment failure…
This is precisely the goal of IBM's Watson if you will remember, an individual doctor only has their own experience - Watson can aggregate data from a virtually infinite number of data points and that knowledge and experience is shared across the network.
Will accidents happen? Yes. But we can learn from them and the collective as a whole benefits, not one individual instance.