All this isn’t to say that a self-driving car must be exposed to every scenario under the sun in order to function robustly. Instead, developers tease out patterns and train vehicles on the fundamental principles that would allow them to fare well in most situations. But there’s a caveat: “Two situations that we as humans might find equivalent, may not be equivalent to whatever kind of software that you’re building,” cautioned Michael Wagner, a co-founder of software technology company Edge Case Research. “You sometimes don’t know whether or not prior development applies to a situation. You don’t necessarily know whether all your simulations are going to be realistic enough to uncover all of the different cases.”