Elevated tracks for the JMZ train run above Broadway and Flushing Avenue. © Krisanne Johnson for the Design Trust for Public Space

A new report from the Design Trust for Public Space outlines how.

The High Line gave new hope to abandoned elevated structures across the United States, to the point that more or less every city wants something like it. But the public spaces beneath active elevated road and rail beds remain at best largely underused, and at worst dark and dusty corridors of neglect. These areas are hardly scarce: there are some 700 miles of elevated transport structures in New York City alone, and ten times that in all America. Today the New York-based Design Trust for Public Space, which jumpstarted interest in the High Line with a 2002 report, has released a massive new mission paper called Under the Elevated, which hopes to do the same for the areas beneath road and rail infrastructure across the city. The report, done in partnership with the NYC Department of Transportation, is the result of a two-year study into these spaces. It calls them “el-spaces.”

Here’s the gist of the problem, as captured by the report: In a dense city like New York, the residual space beneath the nearly 700 miles of elevated transportation infrastructure can no longer be an afterthought. The millions of square feet of these sites, nearly four times the size of Central Park, arguably encompass one of the most blighting influences on the city’s neighborhoods, yet also constitute one of the last development frontiers. This substantial inventory—cataloged for the first time by the Under the Elevated study—represents an untapped public asset that has the potential to radically transform New York’s urban fabric. Under the Elevated goes on to outline some 130 pages worth of design ideas for reclaiming these “untapped” public assets. Some reflect on the success of actual pop-up installations; others remain in the very conceptual phases. The Design Trust and DOT say they’re actively developing several of the projects. We’ve highlighted six cases for New York and other cities with elevated corridors to consider.

Division Street (Manhattan) The area beneath the Manhattan Bridge at Division Street, in Chinatown, is described by Under the Elevated as “dark and dirty from vehicle emissions and bridge runoff, and noisy due to trains running on the bridge above.” Not a terribly pleasant place. But it became at least an engaging one in April 2014, when the Design Trust and DOT installed a pop-up community calendar and red LED lighting. The thinking behind the calendar was that the strip of Division Street under the elevated was a place that many Chinatown locals passed by, but few stopped at. The installation gave them a chance to post weekly events happening in the community: training classes, exercise programs, job or housing notices, and so on. If nothing else, according to the report, the calendar “showed that people are willing to stop and linger in a space that does not fit the traditional mold of a public space.” Future ideas for the site include additional lighting installations that vary based on how the sun slips beneath the elevated structure, and turning the wall of the structure into green infrastructure that collects rainwater from the bridge. Southern Boulevard (The Bronx) Noise from the 2 and 5 trains that travel along elevated tracks above Southern Boulevard, in the Bronx, create what Under the Elevated calls “inhospitable conditions for pedestrians.” So project coordinators tried to counteract those unpleasant sounds with far more appealing ones in a July 2014 pop-up installation they called the “Boogie Down Booth.”

The booth played music from Bronx artists—from Thelonius Monk to the Chantels to Grandmaster Flash—all day and night through solar-powered speakers. It attracted some 1,500 passers-by per week during its pilot run. “The one request that many people voiced was to turn the music up,” according to the report. A longer-term vision for Southern Boulevard would focus on creating an “acoustic barrier” along the sides of the elevated train tracks. The idea would be to trap and contain the noise up top so that it didn’t interfere as much with life down below. The Design Trust suggests having the barrier itself alternate between a solid structure and green walls. Cities are changing fast. Keep up with the CityLab Daily newsletter. The best way to follow issues you care about. Subscribe Loading... Queensboro Bridge (Manhattan and Queens) There are some attractive areas beneath the Ed Koch Queensboro Bridge, in Manhattan and Queens, though most are on the Manhattan side—including an enclosed tennis court and a TJ Maxx. On the Queens side the space beneath the bridge is “much more underutilized, with mostly vacant lots, storage spaces, and parking,” according to the report. One idea for that space (shown here) is to create charging hubs for electric cars and (if the city ever came around to converting its fleet) cabs. A rest station for drivers could be situated there, too, giving something to do while they waited. The Design Trust sees several sites beneath the bridge that could function as charging hubs in a broader city network. Broadway Junction (Brooklyn)

Five subway lines converge at Broadway Junction in Brooklyn, creating what Under the Elevated calls a “tangle of elevated structures.” Aside from some street vendors, there’s little activity going on in the el-space; much of it’s become parking. But a lot of light does shine through the tracks, “creating a lush landscape of opportunistic vegetation throughout the infrastructure maze.”