All cities bear scars, evidence of past planning decisions, made with the best of intentions, that affect urban space in negative ways over the following decades. For more than 40 years, Washington, D.C.’s northwest quadrant has suffered a particularly prominent one where the District’s downtown meets the Capitol Hill neighborhood to the east: A three-block-long, 200-foot-wide opening above the depressed Center Leg Freeway (I-395), which runs beneath the nation’s capital from New York Avenue down to the Southeast Freeway (I-695).

The opening—bounded by Massachusetts Avenue to the north, E Street to the south, 2nd Street on the east, and a handful of buildings along 3rd Street—is a remnant of the nationwide mid-20th-century effort to revitalize cities by bringing high-speed, multilane highways around and through urban cores. Extensive plans for the District included an interstate loop within the city that would stretch from the west end of the National Mall to the Anacostia River on the east. The eight-lane Center Leg Freeway, which skirts along the U.S. Capitol’s west side, was the second segment built.

North of Constitution Avenue, the section of D.C. the freeway would pass through was a largely black and mixed-European working-class neighborhood that had been in long decline as the city suffered from white flight and economic woes. (Partly in response to the District’s difficulties, a complete reorganization of local government in 1967 gave D.C. semiautonomous rule with its first mayor and City Council.) The area was considered blighted, and there was little effort to resist the project. But seven years after construction on the Center Leg Freeway began, dwindling federal budgets and shifting transportation priorities—as well as sustained protests from wealthier communities within the District about other proposed highway segments—took their toll. The D.C. plan was abandoned, and I-395’s abrupt termination at Massachusetts Avenue, in 1973, was its final gasp. (A congestion-easing, subterranean extension to New York Avenue, a few blocks to the north, opened in 1982.)

Four-plus decades later, the scar is finally vanishing, thanks to the 7.5-acre, $1.3 billion Capitol Crossing development from Property Group Partners (PGP). The project will completely cover the opening with five new 130-foot-high mixed-use buildings (including residences) and public space (20 percent of the site, says PGP), reconnect the gaps in F and G Streets, and offer 2.2 million leasable square feet. Currently under way, with the decking to be completed this year and the first building available in 2018, Capitol Crossing is expected to finish build-out around 2022.

Why did it take so long? In short: the city’s decline, which began (as it did in other urban cores) in the 1960s and didn’t end until almost the turn of the century. Since then, the District has flourished by leaps and bounds, and only in the past decade, notes PGP Regional Vice President Bob Braunohler, has the value of real estate risen to the point that a massive, precedent-setting project like Capitol Crossing makes economic sense. “We and New York are about it,” he says. “We’re building land, and the cost of building the land is less than it would be to buy land” of a comparable scale.

In 1988, a local developer, Conrad Monts, acquired the freeway’s air rights from the city and proposed a several-building project. But things fell apart as the relationship soured, for a variety of reasons, over the years. By 2005, the site remained vacant, and Monts and the city were mired in lawsuits. Sensing an opportunity, PGP—then known as the Louis Dreyfus Property Group, which had been active in D.C. for a number of years—approached both parties, brokered a peace, and began negotiating with the city for the site. The process took years, as the two sides had difficulty agreeing on the value of empty space (which happens to have a massive highway running beneath it). The deal finally closed in 2012 with a novel approach from “clever” lawyers at Arnold & Porter, says Braunohler: PGP would purchase the land below the opening directly from the city for $63 million, as opposed to Monts’s air-rights-only lease, but the number would be subject to a formula that takes into account the cost of building the freeway-hiding deck, meaning the final purchase price has yet to be determined.

Neil Albert, who was the city’s deputy mayor for planning and economic development from 2006 to 2010, under then-D.C. Mayor Adrian Fenty, and now heads the DowntownDC Business Improvement District, where Capitol Crossing is located, says, “On the surface, a project like this shouldn’t get done” given the multiple development jurisdictions in the District, “but there was a spirit of collaboration that set in at an early stage. The stars really aligned.” Everyone, that is to say, bought into PGP’s grand vision.

And that vision has entailed a complexity of design, engineering, and coordination between PGP (and its development team) and the local and federal government (which manages the highway, in addition to other D.C. development-related jurisdictional oversight) unlike almost anything else the city has seen. Even before Capitol Crossing’s official May 12, 2015, groundbreaking, PGP spent more than a year preparing the surrounding area by improving and expanding area infrastructure and utilities. These days, the site is an incredible hive of activity as new freeway access and egress points are engineered and the deck gets built atop a never-ending stream of traffic—although certain aspects, such as setting the massive beams that will support the deck, happen only at night.

Skidmore, Owings & Merrill (SOM)—which developed the master plan for Capitol Crossing, is managing the deck construction, and will provide construction administration services until the project is complete—has been at the center of it all. (The D.C. firm of Lee and Associates is the landscape architect.) “There was both an art and a science to calibrating the plan,” says Kristopher Takács, director of SOM’s D.C. office. “On the one hand it’s very much about extending the street grid, restoring the rights-of-way, restoring a pedestrian network of corridors that creates a seamless public realm, and in that way a horizontal urban design exercise. But with the highway it was at the same time an extremely challenging vertical exercise, designing within constraints around the dynamic needs of the highway, influenced by design decisions [above the deck] that hadn’t been made.”

But the ambition that Capitol Crossing embodies isn’t just about good urban planning, impressive engineering, and significant revenue generation for D.C. ($40 million annually in real estate taxes alone, PGP projects); it’s also about pushing the sustainability envelope. And PGP knows green, having built the District’s first LEED Gold and Platinum commercial buildings. “It’s part of our reputation,” Braunohler says, noting that “with this development, because of its scale, we had the opportunity to try different things.” Big things.

It starts with infrastructure: power and water. A freeway-level cogeneration plant on the 2nd Street side will provide the entire site (and possibly surrounding buildings) with electricity and usable heat, saving tenants about 20 percent on their power bill, Braunohler says. Extensive water harvesting at roof and street levels will retain more than 90 percent of stormwater, reducing potable water usage by 45 percent and landscape water usage by 50 percent; what isn’t used will be cleaned before its release into the city’s combined sewer system. And by tapping into D.C’s high water table, Capitol Crossing will capture more than enough groundwater to service all of the site’s cooling towers—no city-provided water needed.

Sean Cahill, PGP’s senior vice president of development and a friend of U.S. Green Building Council (USGBC) founder Rick Fedrizzi, Honorary ASLA, says, “We approached USGBC starting 10 years ago because Capitol Crossing was going to be innovative” in ways the council wasn’t considering, such as an early adoption of “ecochimneys” that will filter parking garage air through ground-level plantings before returning it to the sky, cleaner than the surrounding atmosphere. Cahill credits Bill Browning of Terrapin Bright Green, a noted sustainability strategist who was involved in early working sessions, with bringing “large, out-of-the-box” thinking to the development.

PGP describes its vision as “beyond LEED Platinum certified.” And the USGBC is trying to keep up—happily so. “What they’re doing is taking a much more integrated approach than the current [rating] systems are capable of dealing with,” says Brendan Owens, the organization’s chief of engineering, who uses the word “singular” when describing Capitol Crossing. “They are mirroring a vanguard thinking that blurs the lines between infrastructure and building projects,” he continues. “As the project has evolved, we’ve been evolving our own systems. They’ve challenged some of our thinking, in a positive way.”

The National Capital Planning Commission (NCPC), which in 2009 developed D.C.’s first ecodistrict initiative (a comprehensive initiative to turn a 15-block area in the city’s southwest quadrant into a highly sustainable neighborhood), views Capitol Crossing’s approach with high regard. “This is the first time we’re going to see an actual group of buildings thinking at a district scale,” says Diane Sullivan, director of the agency’s Urban Design and Plan Review Division. “This project is going to pave the way for a lot of district-scale sustainability.”

For many reasons, Capitol Crossing is certain to reverberate throughout the real estate industry even before the project is fully built out, inspiring other cities to reconsider what’s possible with below-grade urban highways. But one of its most profound local impacts will be on future development in D.C., especially the stretch over I-395 immediately to the south. The NCPC, for one, is already starting to think about what comes next. Capitol Crossing, Sullivan says, could be a “starting point for the whole [Center Leg Freeway] corridor to change.” Although the evolution would be many years in the making, it’s not too early for mild speculation.

A block south of Capitol Crossing, at D Street, sits the U.S. Department of Labor’s 1.8-million-square-foot headquarters, almost half of which covers the Center Leg Freeway to Constitution Avenue. Completed in 1975, it was among the first federal buildings to acquire air rights for its development. In late 2015, the General Services Administration announced its readiness to find a new Labor headquarters and release the 10.5-acre site (a large portion of which is not over the freeway) to the private sector. Given the development forces at play in D.C. and the parcel’s proximity to the Capitol and the National Mall, it’s easy to envision mixed-use commercial and residential buildings, parks, and more atop a new state-of-the-art platform 10 to 20 years from now.

Between the Labor building and Capitol Crossing, however, I-395 is only partially covered by a plaza bridge that belongs to the U.S. Tax Court, to the west, and was designed by the court’s architect, Victor Lundy, as part of the 1974 federal project. A celebrated example of federal modernism, the Tax Court was given historic designation in 2008 and so will be around for many decades. Which means the plaza will remain as well, along with the large openings on either side that provide a view to the freeway beneath—constant reminders, in the heart of the nation’s capital, of America’s landscape-altering obsession with automobiles. Not every scar can be completely erased.

Project Credits

Developer Property Group Partners, Washington, D.C. Master Plan Skidmore, Owings & Merrill, Washington, D.C. Landscape Architecture Lee and Associates, Washington, D.C. Architecture Kevin Roche John Dinkeloo and Associates, Hamden, Connecticut; Kohn Pedersen Fox Associates, New York; and Beyer Blinder Belle, Washington, D.C. Traffic Engineer STV, Washington, D.C. General Contractor Balfour Beatty Construction, Fairfax, Virginia. Structural Engineer Leslie E. Robertson Associates, New York.