"(T)here are few cities whose alleys offer more possibility than Los Angeles. The USC Center for Sustainable Cities, which is leading the alley campaign here, found recently that there are 12,309 blocks of alleys in the city -- 914 linear miles' worth, roughly the distance between here and Portland, Ore., even if some are just 10 feet wide.
Particularly in older, poorer neighborhoods, where many of them are located, alleys are often dens of crime and blight. But the researchers see something else. They see, all told, more than three square miles of underused land -- about half the size of Griffith Park -- a precious resource in a region starving for vacant land and public space.
They propose lifting ideas from cities such as Seattle and Baltimore while incorporating new ideas to create the most innovative alley overhaul yet: ribbons of eco-friendly, civic-minded spaces coursing through neighborhoods like a spider web."