You use a test set of scenario&#x27;s on which you don&#x27;t train but only measure effectiveness. When accuracy on the test set exceeds your chosen threshold, that is good enough.<p>What is the accuracy of the human brain in recognizing traffic situations? It is probably not that hard to get a NN to do better, even if periodically it still causes an accident. This is the uncanny valley effect for self-driving cars. It&#x27;s not enough to be better than average humans at driving, which i think they already are, they have to be perfect at driving for people to trust them.