I remembered a website with a visual illustration of how much the walking range of children has declined in Britain during four generations of a family living in the same town. The map, based on where the great-grandfather, grandfather, mother, and son in the same family walked, shows a stark narrowing in how far children walk on their own.[1] In my town, in Minnesota in the United States, I walked regularly on the city trail system with my children to the county library branch (about a mile away, in one direction from our home) or to the shopping district (about a mile away in the other direction on our same city trail system). All of my children have been able to do those walks on their own, or with an older sibling accompanying a younger sibling, for a long time. My children can be out and about in our neighborhood without anyone hassling them. It should be that way for more children. Most cities in the United States these days are objectively safe enough for children to walk outdoors alone at the ages described in the article kindly submitted here (I don't know specifically about that part of greater DC in suburban Maryland,[2] but I would guess it is safe enough too), and children are better off walking and exploring more rather than being confined indoors or in cars on parental drives to other buildings all day.

AFTER EDIT: Many comments posted after mine here was posted are bemoaning the lack of freedom children have to roam outside today, but that remains to be proven. I think the most astute comments here point out that we really don't know whether there are a lot of external pressures on parents to keep their children from walking outside alone, or just a change in parenting practices that makes that less common. I can testify that here in Minnesota, my children are far from the only children who walk outside by themselves at the ages reported in the news anecdote here. Compared to my childhood growing up not far from where I live now, I think children spend too much time indoors in general, and not enough time outside, but I have no fear of the police or the child protection authorities here when my children are outside. We are homeschoolers, so my children have spent a lot of time outdoors during normal school hours. That has never been a problem here, as everyone knows that homeschooling is legal in Minnesota. My children have often walked to the public library by themselves during school hours. New parents (some of the commenters on this thread) need not be afraid of bringing up their children to take walks by themselves outdoors.

[1] http://bigthink.com/strange-maps/571-the-great-indoors-or-ch...

[2] https://www.google.com/maps/place/Woodside+Park,+Silver+Spri...