Seattle is definitely out of the norm. Even Northgate, which doesn't have sidewalks in places, has roundabouts on the collectors to discourage speeding. I grew up in a poverty-level suburb and you were walking miles away on cramped sidewalks even to get to a grocery store. When I grew up cars couldn't accelerate that quickly so it wasn't that scary, but these days cars can travel at > 60 mph on collector roads between lights.