Yeah, I live in New York City, which is much more walkable than the suburb that I grew up in…but still feels less viable for letting my kids range freely. There are just so many more cars, and there is always construction and/or otherwise obstructed bike lanes and sidewalks—you have to be extremely aware and defensive on a bicycle. On the other hand, I grew up in a little cul-de-sac that was perfect for kids to bike around precisely because cars were infrequent. We walked to and from grade school and middle school unsupervised, with our friends who also lived in the neighborhood. In NYC, parents are a bit nuts about schools, so they rarely just walk their kid to the nearest school—they end up taking the train and/or driving to whatever place they think will maximize their kid’s college prospects, which results in a lot of unnecessary transportation.