My first home purchase was in a planned subdivision in Illinois called Hometown, which generally mimicked the Milwaukee Ave idea of no front streets, big porches and encouraging neighbors to interact through traffic free and reduced traffic streets.

Unfortunately, most people just came and went through their garage on the alley, and the front streets were pretty much deserted. There was very limited parking, especially for visitors, which for a suburban community was problematic.

The housing market crash probably didn't allow Hometown to reach its full potential. During and after the housing crash the community started to attract owners and renters who were more interested in the value-priced housing than the idea of the walkable neighborhood, the business node never developed, and when I was there the most mature plantings were only about 2 years old. Many parts of the subdivision remain unfinished even a decade plus later. So certainly it's not an exact match to a city scape and closing established streets, but through personal experience I would say closed streets are not as attractive an option as may be at first glance.

I believe a better option to closed streets in the city would be to cul-de-sac a number of streets per neighborhood to encourage more kids and families in front yards, but still provide local vehicle access and parking.