I wonder how much the built environment impacts the independence we can give our children. For instance, regarding the milestone of safely crossing the road tha

I wonder how much the built environment impacts the independence we can give our children. For instance, regarding the milestone of safely crossing the road that this article mentions, does the common milestone age decrease in more pedestrian-friendly places? It's one thing to cross a one-lane, slow-traffic narrow street in Europe versus a wide, high-speed one characteristic of most American suburbs.