Autonomous Car Collides with Bus: an illusion of abstractions?

This model of abstraction, call it the N&S model, is, what I will call a "context pro-functional" accumulator. It sets up a checkpoint for the selection of candidates in a given class of situation, call it [S1], to moving up the ladder of abstraction. It allows items to climb that meet certain functional requirements for an AI construction goal. It may even cull out an [S1]-dys-functional elements, if they are of concern. But such dysfunctional elements may be overlooked or disregarded, as being, for example of low probability of happening, or of low enough cost in the long run to allow to pass through.