The African American Civil War Memorial. Before, the only parkland at this intersection was the grassy plot on the right. Image by wgestalten, via Flickr licensed under Creative Commons.

Nearly 300 small parks scattered around the District of Columbia are owned, and often neglected, by the National Park Service. Dozens of these are little more than traffic islands, remnants left over amidst the many complicated multi-leg intersections along angled streets — a legacy that dates back to the L'Enfant Plan.

Oftentimes, proposals to upgrade these parks are met with a shrug and a sigh of “well, if only Congress cared.” Rarely, these proposals are met with Congressional action.

Yet there's another, simpler way for the District to enlarge and activate some of these parks, without consulting Congress. Even if NPS controls a triangular park, the District Department of Transportation controls the street segments around the triangle. In many cases, at least one of those three segments sees comparatively little traffic.

Simply re-routing cars around the park can free up enough space to double the size of the park. Since DC owns the space underneath the road, it can add whatever amenities are needed there — leaving the empty triangle as extra open space.

In urban design parlance, doing so would be converting a “detached square” — one, like Franklin Square, that's separated by streets from the buildings around it — to an “attached square” that fronts directly onto buildings. Not only does the result mean more green space, but without cars in the way, the square feels like an extension of the urban fabric around it rather than a space apart.

Found space for a park along U Street

One fine existing example is the African American Civil War Memorial, notes contributor Patrick Kennedy: “10th Street, on the short block between U and Vermont, was closed to create the eastern entrance for the U Street Metro, and then the plaza became the African American Civil War Memorial.”

The highlighted area was 10th St. NW, but is now part of a larger park housing the African American Civil War Memorial. Image by Landsat, via Google Earth used with permission.

An aerial look reveals that doing so tripled the size of what was an 1/8 acre triangle, and that pretty much everything within the memorial park — the Metro entrance and bus stop, the statue, even most of the inscription wall — sits within what was the 10th Street right-of-way. The former triangle park is an off-limits zone of subway ventilation grates.

The block of houses fronting 10th Street didn't completely lose access, either. They gained a wider sidewalk, and still have alley access to their garages. Meanwhile, a slip lane was added on the Vermont Avenue side, which makes up for some of the parking spaces or front-door access that might have been lost.

Space for rain gardens in Petworth and at Eastern Market

Abby Lynch writes that “DDOT reclaimed a tiny stretch of 9th street NW, between Shepherd and Taylor, when they re-did that stretch of Georgia Avenue back in 2010. They installed a rain garden and wider sidewalks.”

As with 10th St. NW, the impact on parking spaces was negligible because angled parking spaces were added nearby.

Similarly, plans for redesigning the large plaza at Pennsylvania and 8th Street SE, atop the Eastern Market Metro, replace 130 feet of D Street SE (in front of Dunkin' Donuts) with rain gardens.

The park at CityCenterDC is on the right, and the Eye Street woonerf at left. Image by the author.

Even partially diverting traffic can work wonders

If continued auto access is needed, the street can be redone as a shared space (or woonerf) instead — with occasional, but slow, auto traffic. Lafayette Square, in front of the White House, is one of the most pleasant parks in downtown largely because there's almost no auto traffic on three of its sides.

The Park at CityCenterDC, at 10th and Eye NW, is separated from the rest of the site via a shared space segment of Eye Street that's almost always off-limits to cars, but open to pedestrians and cyclists.

A recent report recommends a woonerf design for the highlighted part of Eye St. NW, effectively enlarging Chinatown Park. Image by Landsat, via Google Earth used with permission.

A recent ULI Washington advisory panel recommended a woonerf and associated changes for another nearby stretch of Eye Street, between 5th and 6th streets NW. This approach would better tie Chinatown Park to local anchors like the Chinese Community Church, the Chinese Consolidated Benevolent Association, and Sixth & I, all of which sit across Eye Street. The reclaimed space for pedestrians would be larger than the existing park's small lawn.

Even where the surrounding streets are heavily trafficked, the surrounding parking lanes can be repurposed for park use without impacting through traffic. This could either be done on a permanent basis, as with this proposal for Longfellow Park at Connecticut and M, or temporary—as happens every lunchtime, when food trucks line up around Farragut Square.

Temporary closures can also work to activate forgotten triangle parks, as with the Bloomingdale Farmers Market on R Street NW, between 1st and 2nd.

All the way down the line

A more systematic approach can free up acres of open space along a street corridor while also streamlining traffic flow. In Manhattan, many triangular parks resulted where diagonal Broadway slices across the rectilinear gridiron. For decades, tourists flocked from around the world to places like Times Square, only to find a traffic island rather than a proper square.

But in 2009, NYC DOT's “Green Light for Midtown” initiative redesigned numerous acute-angle intersections along a 2.3-mile stretch of “Broadway Boulevard” through Midtown Manhattan by re-routing car traffic off Broadway and onto the grid.

Herald Square, before and after traffic was diverted off Broadway. Image by NYC DOT licensed under Creative Commons.

Doing so found several acres of new park space, creating room for thousands of seats — and increasing pedestrian traffic along the way. The change also improved traffic flow (with higher travel speeds) and reduced injuries and crashes by removing closely spaced intersections.

Which avenues might benefit from a similar approach in DC? Share your thoughts in the comments.