I'd argue that most American local streets are unsafe anyway: I've seen Spanish highways with fewer lanes than suburbian streets with no commercial. But the distances to connect 500 bedrooms, placed in 1/3rd of an acre lots, are so large that ultimately roads are overbuilt to fit anything. Suburban streets with traffic under 1 car a minute in the daytime, with 3 or 4 lanes, set to a 30mph max, where you'd do 60 except for the fact that it's full of driveways coming in and out. Why do we even allow a lone house connect to a road like that via a driveway, where the neighbor will go into the street in reverse? It's madness, and is all over the midwest. So we don't even have to get into the stroads.