  In this paper, we present a rigorous modular statistical approach for arguing
safety or its insufficiency of an autonomous vehicle through a concrete
illustrative example. The methodology relies on making appropriate quantitative
studies of the performance of constituent components. We explain the importance
of sufficient and necessary conditions at the component level for the overall
safety of the vehicle as well as the cost-saving benefits of the approach. A
simple concrete automated braking example studied illustrates how separate
perception system and operational design domain statistical analyses can be
used to prove or disprove safety at the vehicle level.
