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Benefitting From a Cover Up: How Concealing Urban Highways Can Create Parkland

A twelfth excerpt from the recently released book published by Island Press called Urban Green: Innovative Parks for Resurgent Cities. In this post, we look at some cities who have created parkland by concealing or burying highways.

Urban radicals want automobiles banned. Urban moderates can perhaps live with cars as long as they’re neither seen nor heard.

In European central cities the radicals have the upper hand. U.S. cities are increasingly settling for a compromise–an expensive compromise–by putting freeway segments underground and covering them with parkland. Whether called a lid, deck, bridge, or tunnel, there are already at least 24 of these parks in the country and a dozen more somewhere in the planning pipeline. Surprisingly, because of both undulating topographies and the fact that many cities are already operating on multiple above-and-below-ground levels, there are numerous opportunities to construct more freeway deck parks. As the impact of automobiles becomes ever less welcome in cities, these lids have moved from the novel to the accepted to, increasingly, the expected. The sometimes considerable cost has gone from being dismissed as “porkbarrel” to being redefined more positively as amenity investment with high economic payback.

Drivers passing through Seattle’s downtown core on I-5 go underneath the city’s five-acre Freeway Park, built in 1974.

In a study carried out by the Center for City Park Excellence in 2007, it was found that the average size of the nation’s freeway parks is about 8 acres and each covers about 1,600 linear feet of highway. Most famous is Seattle’s aptly named Freeway Park, designed by the Lawrence Halprin firm and opened with great fanfare in 1976, but the concept actually goes back to 1939 when Robert Moses constructed the Franklin D. Roosevelt Expressway along Manhattan’s East River, tunneled it under the mayor’s home at Gracie Mansion and constructed 14-acre Carl Shurz Park on top. In 1950 Moses did it again, in Brooklyn, when citizens rose up against a planned expressway through the center of Brooklyn Heights. As a compromise he added the 1/3-mile long Brooklyn Promenade with its supreme view of lower Manhattan, remarking self-satisfiedly at the ribbon-cutting, “I don’t know of anything quite like this in any city in the world.” The latest have been New Jersey’s innovative highway redesigns in Trenton and Atlantic City and the Rose Kennedy Greenway park blocks over Boston’s massive “Big Dig.”

The Interstate Highway System, when it was originally conceived in the early 1950s, was designed to link but not penetrate cities. By the 1960s, however, the distinction had been forgotten. Highways became the preeminent tool of urban renewal and redesign, and vast swaths of urban real estate were paved over. Waterfronts were blockaded in Portland, Cincinnati, Hartford, Cleveland, Philadelphia, and San Francisco. Nooses of concrete were wound tightly around the downtowns of Dallas and Charlotte. Trenches of noise and smog cut through Boston, Detroit, Seattle, and Atlanta. Stupendous elevated structures threw shadows over Miami and New Orleans. And wide strips of land were taken from large, iconic parks in Los Angeles (Griffith Park), St. Louis (Forest Park), Baltimore (Druid Hill Park), and San Diego (Balboa Park).

A few downtown parks actually survived the devastation thanks to the intervention of historic preservationists, including Lytle Park in Cincinnati and the National Mall in Washington, D.C. In both cases, citizen outcry forced the highway builders to tunnel underneath (although technically Lytle Park was leveled and then reconstructed three years later).

But it wasn’t until the construction of Freeway Park that the “deck the freeway” concept began getting some serious attention. Because of the constrained, hourglass geography of Seattle, Interstate 5 was a particularly damaging road, and the environmentally oriented populace was dismayed by the impact. “There was a large moat of traffic between downtown and historically residential First Hill neighborhood,” says Freeway Park Neighborhood Association President David Brewster. But the city was lucky–not only was I-5 sunk into a deckable trough as it passed downtown, but a former Seattle mayor, James “Dorm” Braman, had just been appointed assistant secretary of transportation for urban systems and the environment by President Richard Nixon. Braman was amenable to the deck, which was promoted by civic leader Jim Ellis and paid for under the city’s “Forward Thrust” bond initiative. Freeway Park opened in time for the bicentennial and garnered coast-to-coast attention. “It was a model for other cities to heal the scar that cuts right through a neighborhood,” says Brewster.

Freeway Park was beautiful and memorable, but it failed on one major count: acoustics. At 5 acres it couldn’t completely muffle the sound of traffic, and the park experience is accompanied by a constant white noise–not obtrusive, but not minimal, either. Phoenix’s 10-acre Hance Park seems to have solved the noise challenge (as has Seattle’s new, much larger Sam Smith Park). Labeled by the Phoenix New Times “a rare Phoenix instance of nature over traffic–in this case, literally,” Hance Park is decked over the Papago Freeway, uniting uptown and downtown and providing a park adjacent to the city’s central library. The freeway (Interstate 10) was originally planned as an elevated bridge through downtown but opposition by citizens and the Arizona Republic killed that idea in a 1973 ballot measure. Not until ten years later did the city finally accept a below-grade solution with the park as a key sweetener. Hance Park opened in 1992 and today is the site of a Japanese Garden. As a sign of success, it is gradually becoming surrounded by a growing number of upscale condominium towers.

By decking over a portion of I-35, Duluth, Minnesota, was able to save its Rose Garden and provide a park connection directly to its Lake Superior. Credit: Minnesota Dept. of Transportation.

Freeway parks have also bridged the divide between cities and their waterfronts. In Duluth, Minnesota, a plan to build Interstate 35 along the Lake Superior shoreline generated intense opposition from environmentalists and historic preservationists. By shortening the planned freeway’s length (and gaining the backing of powerful Duluth then-congressman John Blatnik) the city used the savings to pay for park covers. Ultimately, three different deck parks were built, including one that saved a historic Rose Garden.

Construction costs for deck parks can be wincingly high, but there is also an upside–the land itself is generally free, made available through air rights by the state transportation agency. In center-city locations this can amount to a multimillion-dollar gift. Land near the Santa Ana Freeway by Los Angeles City Hall, for instance, goes for between $2 million and $3 million an acre. In near-downtown San Diego by Balboa Park an acre is worth up to $13 million. Regardless of cost, the actual force driving–and making feasible–most deck parks is the opportunity for neighboring private development and redevelopment. In Trenton, the New Jersey Department of Transportation spent $150 million on the new 6.5-acre Riverwalk deck over U.S. 29, linking the city to the Delaware River. In response, notes Trenton Planning Director Andrew Carten, “The project resulted in a significant spike in interest and the sale prices of property. After all, would you rather look over 600 trucks barreling past every day, or a scenic park and river?” One lot, worth $120,000 preconstruction, was developed with six housing units that sold for $200,000 each. The presence of the park also helped recruit a new 82-unit market rate residential building.

The cost of the Boston Central Artery–the gargantuan project to bury the elevated Fitzgerald Expressway, which yielded as a surface byproduct the Rose Kennedy Greenway–has caused some people to doubt the feasibility of such parks in the future. But the Central Artery was primarily a transportation project that combined massive demolition along with even more massive construction. It also included major bridges and underwater tunnels. Of the $14-billion price tag, only an estimated $40 million was attributable to the mile-long stretch of four parks that opened to the public in October 2008. Certainly not inexpensive, but very much in line with many other new, showcase destination parks that are helping to redefine the nation’s premier urban centers.

The Woodall-Rodgers Park, planned over a three-block stretch of the Woodhall-Rodgers Freeway in Dallas, will connect the currently separated downtown and arts district from the Uptown neighborhood. Credit: Office of James Burnett.

Projects where freeways are already below-grade are more feasible, and four particularly high-prospect opportunities are currently being explored in St. Louis, Cincinnati, Dallas, and San Diego. In St. Louis, Mayor Francis Slay is promoting the “three-block solution,” a plan to cover a portion of I-70 between center city and the world-famous Gateway Arch. “We’re trying to get the annual 3 million visitors to the Arch into downtown St. Louis,” says Peter Sortino, president of the Danforth Foundation, which is handling the planning. “We’re also trying to help those already downtown more easily reach the Arch and the Mississippi riverfront.” An early estimate put the cost at a minimum of $40 million. Cincinnati faces the identical situation. An interstate highway, Fort Washington Way, is a barrier between downtown and the parkland along the Ohio River. Cincinnati had an opportunity to construct a five-block-long park deck during a road reconstruction (and narrowing) in 2007, but shied because of cost. As a compromise, the new Fort Washington Way was equipped with $10 million worth of steel pilings capable of supporting a future park.

Dallas, on the other hand, is plunging ahead with planning and funding a park over a stretch of the Woodall-Rodgers Freeway. The freeway separates the city’s downtown and arts district from the Uptown neighborhood, and a three-block park cover is seen as both improving the urban form and opening up new opportunities for development. A trolley line would run through the park, and condominium towers are expected to flank it on both sides. A developer of a nearby tower is enthusiastic, telling the Dallas Tribune that the park “will be a fabulous amenity to [my] building.” The park’s price tag is estimated at more than $60 million, but Dallas’s confident and ardent boosters are busily raising matching funds from private sources.

Trenton, New Jersey’s new 6.5-acre Riverwalk deck over U.S. 29 links the city to the Delaware River; it is credited with sparking development and reinvestment in nearby properties. Credit: Vollmer & Associates.

In San Diego, downtown interests are in the early stages of evaluating decking a few blocks of I-5 so as to forge a link with Balboa Park. The city has been in the midst of an unprecedented center city residential construction boom, and the highway presents a major barrier for the thousands of apartment dwellers who have little access to green space. Meanwhile, activists in Los Angeles are determined not to lose their “Freeway Capital of the U.S.” moniker and are evaluating eight different sites. “We want to now become the ‘Freeway Deck Park Capital of the World,’” said Don Scott, chair of the Hollywood Central Park Coalition.

Despite the cost of a park deck, there are numerous sources of local, state, and federal funds that can be cobbled together, particularly if an analysis shows that associated development will generate significantly more tax revenue. Often the deck superstructure is paid for by the federal government while actual park development is financed by the city: Phoenix spent $5 million landscaping Hance Park. The Trenton deck came about through reconstruction of a state highway and was paid for by the state of New Jersey. In Cincinnati, 20 percent of the narrowing of Fort Washington Way was financed through private dollars, including $250,000 from the Cincinnati Bengals football team.

Olmsted Park and Potomac River Waterfront Park Selected as “Frontline Parks”

Each month, City Parks Alliance recognizes two Frontline Parks to promote inspiring examples of urban park excellence, innovation and stewardship across the country in the face of shrinking municipal budgets, land use pressures and urban neighborhood decay.

March’s selections celebrate historic design and new innovations.

Olmsted Park, Brookline, Mass. Credit: Brookline Parks and Open Space Division.

Depending upon where you live in the United States, the culture of parks and open space can vary according to when the system was established and who planned it. It is not unusual to hear envy for those parks and systems designed by Frederick Law Olmsted or Daniel Burnham. Indeed, many of these parks were constructed before the cities that now surround them, shaping urban form in profound ways. Similarly, it is not unusual to hear the stewards of those legendary parks and systems struggle with how to make those spaces relevant for contemporary users. New parks have an advantage in embracing the most current engineering and technologies from the outset, rather than a retrofit. This month’s featured parks demonstrate how both old and new parks achieve relevance in cities today.

Olmsted Park in Brookline, Massachusetts began construction in 1890. As a gem in Olmsted’s Emerald Necklace in Boston, the namesake park includes three ponds and a meandering stream that were, at that time, engineered solutions to the problematic Muddy River. Olmsted linked the man-made improvements with natural formations, creating a scenic ribbon of groves, lawns, and water features. Thanks to the hard work of the Brookline Parks and Open Space division and its four partners, the historic landscape has been restored with new plantings, better views, and easier access. Click here to read more.

Woodrow Wilson Bridge Trail, Oxon Hill, Md. Credit: Maryland-National Capital Park and Planning Commission.

Nearly 120 years later, the Potomac River Waterfront Park in Oxon Hill, Maryland opened in 2009. The site along the Potomac River features a landscaped superstructure – a deck over I-95 that links trail systems in Maryland and Virginia via a connection to the Woodrow Wilson Bridge over the Potomac River. It also features a unique solution to moving trail users from the ground to the deck by means of a helix of “foamed concrete.” In addition to the trail opportunities, the park features a panoramic view of Washington, D.C. and its environs. As you can imagine, this kind of project includes many local, state, and federal partners committed to creating 21st century park solutions. Read more.

Frontline Parks is generously supported by DuMor, Inc. and PlayCore.

Creating More Parks, Less (Visible) Traffic in LA

Jason King at Landscape+Urbanism provides a summary of plans to cap sections of freeway in Los Angeles with a linear44-acre Hollywood Central Park.

TPL’s Center for City Park Excellence took a look at this trend a few years ago and provided an article on the capping-freeways-with-parks movement. It should be noted that while the Big Dig has been seen as a costly public project in the billions of dollars, it was a tunneling project in addition to many other big ticket items such as bridges and tunnels underwater. Many freeway parks are built on decking, or a series of bridges, that require less extensive work than a tunnel — and many have been and can be, as in Los Angeles, built over already below-grade viaducts.

Below-grade freeways can be found in Charlotte, Atlanta, Cincinnati, the Twin Cities, Portland and countless cities across the country. Seattle, Dallas, Boston, Hartford, Philadelphia, New York City and even Duluth, Minn. have done or are in the process of capping these areas with parks. After a while, many of the cities without them, as is the case in Los Angeles, may say, “why can’t we have a park over a freeway?”

As cities experience the colliding forces of creating more humanistic cities and a reluctance to completely remove freeways, placing parks on top of these areas may be the one choice everyone can live with.

(This all being said, it may be fitting to just remove some freeways altogether — here’s some suggestions from the Congress for the New Urbanism.)

Fewer Megaprojects, More Megaparks

Next American City’s Diana Lind has a “what’s in store in 2010″ list on the magazine’s website, and one of them is:

Fewer megaprojects, more megaparks. A project that has long intrigued me and will be covered in the magazine in the summer of 2010 is the The Park in Dallas. What’s so special about it? It’s 5.2 acres on top of a freeway! Calling St. Louis! Calling Milwaukee! And really any other city with a highway that separates its city.

TPL’s Center for City Park Excellence wrote an article on the concept of covering freeways with parks. Its something for any city with a below-grade freeway to consider. And there are many: Atlanta, Los Angeles, St. Paul, Minneapolis, Hartford, Chicago, St. Louis, Cincinnati (which actually has started but needs to finish) and many more.

St. Louis Using Parks as Tool of Renewal

In our posts, we’ll be looking for older, industrial cities that are using parks as tools for renewal – both as ways to transform abandoned industrial land and as drivers for economic development. (See our post on Detroit for one example.) In the October, 2008 issue of Landscape Architecture we learn of the many ways St. Louis is investing in parks and public spaces as part of its renewal strategy. According to the article:

  • City Garden, the two-block sculpture garden in the Gateway Mall (under construction)
  • Gateway Mall master plan (completed)
  • Old Post Office Plaza, an exciting $8.2 million project that places a valuable open-space attraction in the central core (under construction)
  • New streetscape for an emerging loft district (completed; streetscape guidelines are now in place for additional downtown phases)
  • Development of downtown housing for a growing residential population, a high priority for the area’s revival (ongoing)

Other projects that are pending include the Chouteau Lake park and parkway project on the edge of downtown that will connect to the city’s famed Forest Park (phase one construction awaits pending federal funding); and an effort to connect the downtown to its riverfront and redevelop the Arch grounds on the riverfront. This latter effort could involve decking the below-grade freeway that currently tears the downtown and riverfront asunder. (For more information on city’s decking highways, see this article by the Center for City Park Excellence.)

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