We are discussing the comment you replied to: "the planners' great idea of mixing cars and people on the same street." which was in reply to a link discussing that idea.

And you wrote that you thought that was safe for 10-year-olds. Which it is not. A street with pedestrians and cars on it is called a "street" and is not a safe place for any pedestrian, let alone a 10-year-old. Which makes it a stupid, dangerous idea, but one that is cheap for the planners to implement, hence its popularity.