I live in a subdivision and ride through many of them regularly. I live in the suburbs and the Detroit Metro area was built in one square mile grids. There are mile roads (I live off of 9 Mile Rd) and named roads and most have a good amount of traffic. So the subs are a good way to add miles and eventually get to a mile rd that is not too busy. None of the subs are gated as they are all 50+ years old and the streets in them are lightly traveled and in reasonable condition.