My point is not that children would jump in front of cars. It’s that they would run toward the curb with a heading and velocity that would dictate a collision, then stop just before entering the street. They would do it for the main reason that children do things - because it would be hilarious to watch self-driving cars leave a patch on the road and jerk their passengers back with seatbelt pretensioners. If you don’t actually set foot in the street, you’re not breaking the law.

Changing the average travel speed from 45 kph (the city-wide speed limit in New York) to 10 kph would be a disaster.