While this is a really interesting concept, I don't think it's the most practical. At first, it reminds me of all the movies and shows where it shows kids jumping rope and playing hopscotch in the alleys or empty streets.
And then I get a flash forward scene where a kid goes splat. I know kids play in the streets in a lot of areas, especially when all the residential cars are away at work. Kids also run out into traffic, don't pay attention, and shouldn't necessarily be 'encouraged' to be playing in the streets. It's too bad, though. It's a really great way to double up on usable space.