If you're going to have a dense, intercity area, I suppose I'd argue that the question isn't about "human-driven cars", which brings up the largely unrealistic consideration of self-driving cars on ordinary roads, but simply: Build the city center entirely around public transit. Rail is incredibly efficient, and in a system where you are designing the city first, I'd forgo roads entirely. Why bother with buses if you have free reign where to put your rails? And as a Chicagoan, I can say that nobody in their right mind drives a car into the intercity to begin with.
Modern subway systems are automated with barrier walls and doors making it near impossible for a human to end up on the tracks. If built like this from the get-go, collisions between transit and pedestrian could be virtually zero. Plan your stations based on the distance needed to reach EVERYWHERE in a reasonable walking distance, make sure your system has the capacity to meet the daily working population, and you really don't need direct A-to-B transportation.
Modern subway systems are automated with barrier walls and doors making it near impossible for a human to end up on the tracks. If built like this from the get-go, collisions between transit and pedestrian could be virtually zero. Plan your stations based on the distance needed to reach EVERYWHERE in a reasonable walking distance, make sure your system has the capacity to meet the daily working population, and you really don't need direct A-to-B transportation.