The urban streetscape is ­degrading.

Take a walk down Broadway on the Upper West Side from the 100s to the 70s, as I did Sunday, and you'll see it everywhere. It seems every barren storefront with a rental sign in the window has ­become impromptu outdoor housing for a homeless person.

There are many such storefronts — ironic signs of prosperity, not recession. Rents have risen so high that small businesses often can't afford to continue and landlords will keep a storefront unoccupied for a very long time to secure a wealthy customer willing to take a very lengthy lease (i.e., a bank).

The number of people living on the street in the neighborhood, or at least taking up daytime residence to beg for change, has skyrocketed from a mere handful to several dozen or more.