As we continue our conversation on the city, we turn to traffic and begin with the big related tech story \u2014 what happened to self-driving cars? In this episode, my colleague Delian provides a lay of the land for the space, and we talk about a world of perfect self-driving cars. What does that look like? Would it have any impact on traffic? If not, what? Why is this important? We also talk about tech risk broadly, shortening the feedback loops of human decision making, collecting data for self-driving cars, different approaches to this, and artificial intelligence, why it seems like all of this has gone a little slower, frankly, than folks were hoping a few years ago, and how it\u2019s shaping up today.