It can include mass transit too. For a practical example, 10km covers all of Washington DC proper if you start at the center, nearly all of which is walkable/bikeable/transit-able.

Rural areas too. I made the mistake of walking down to the store when I lived in rural Colorado. A Truck almost turned me into a paste when it blindly took a turn.

Well that's the point I think. In practically all of the US you can't even take a sidewalk where you want to go. It gets even worse if you want things like walk signals or to avoid huge intersections, or even mass transit at all.

Not only that, our built environment is uninviting to walk in because it's built for cars. When have you ever walked by a parking lot and said "Oh my god, that parking lot was amazing, I want to spend time around it"? Yet we require by law parking lots to be built everywhere in America. We have legally compelled property owners to build something ugly.

Thanksgiving is coming up. Black Friday is the busiest shopping day of the year. Drive around, notice how on the busiest shopping day of the year, most commercial parking lots still aren't full.

> Thanksgiving is coming up. Black Friday is the busiest shopping day of the year. Drive around, notice how on the busiest shopping day of the year, most commercial parking lots still aren't full.

Sounds heavenly. But in reality, my wife (who actually likes going out on Black Friday, I don't know why) will be circling the lot waiting for a spot, any spot, even at the outer edge. It's nuts.

"Practically all of the US" includes nowhere I've lived, and I've moved around a fair amount. Some places are worse than others, but sidewalks are very much a thing more often than not.

Practically all of the US includes almost everywhere I have lived except for major cities. Especially in the Midwest and ESPECIALLY in the South walking to get groceries is a death wish.