Is There a Crystal Clear Definition of Safety for AVs?

Is there a crystal clear definition of safety in a world where cars are driven by human beings? Marjorie, I'm kind of getting philosophical here, but kind of another basic question. As I hear you talk about safety is what is the relationship between safety and risk? Well, it's interesting that you use the word philosophical because I actually have read a couple of literally philosophical articles on that. You outlined these three categories that we can kind of use to consider AV safety: measurements, processes and thresholds.