Linda Owen, president of the Woodall Rodgers Park Foundation, shows off the construction site of Dallas' The Park project, which buries the highway under green space.

PARKS PROPOSED OVER HIGHWAYS PARKS PROPOSED OVER HIGHWAYS City Highway Cincinnati Interstate 71/Fort Washington Way Dallas Woodall Rodgers Freeway Los Angeles Hollywood Freeway Minneapolis I-90/I-35W Portland, Ore. I-405 Sacramento I-5 St. Louis I-70 San Diego I-5 Santa Monica, Calif. I-10 Seattle Alaskan Way Source: Center for City Park Excellence, Trust for Public Land Enlarge By Mei-Chun Jau, for USA TODAY Dallas' The Park project includes a 5-acre park on top of the Woodall Rodgers Freeway that cuts through downtown Dallas. Urban parks take over downtown freeways Cities are removing the concrete barriers that freeways form through their downtowns — not by tearing them down but by shrouding them in greenery and turning them into parks and pedestrian-friendly developments. This gray-to-green metamorphosis is underway or under consideration in major cities seeking ways to revive sections of their downtowns from Los Angeles and Dallas to St. Louis and Cincinnati. Transportation departments are not opposed as long as the plans don't reduce highway capacity. In most cases, traffic is rerouted. "It's the coming together of people wanting green space and realizing that highways are a negative to the city," says Peter Harnik, director of the Trust for Public Land's Center for City Park Excellence. "Covering them with green space gives you a wonderful place to live and work." GREEN HOUSE: Small victories to a greener life Groups that are not always on the same page — environmentalists and developers — are embracing the "capping" or "decking" efforts for different reasons. Environmentalists encourage more trees and grass to offset carbon emissions and promote walkable neighborhoods to reduce reliance on cars. Developers are eager for space to build on in prime downtown locations. Citizens want parks and amenities they can reach on foot. "Highways are extremely destructive to the fabric of urban life," says Harnik, author of Urban Green: Innovative Parks for Resurgent Cities. "The noise that emanates from it, the smell." Capping freeways dates to the 1930s. A recent example is the Rose Kennedy Greenway over Boston's "Big Dig," which created open space by putting elevated roadways underground. The resurgence of downtowns has turned available pieces of land into hot commodities. At the same time, the drumbeat for more parks in smog-choked cities is getting louder. "It's essentially like creating oceanfront property," says Linda Owen, president of the Woodall Rodgers Park Foundation in Dallas. "It's an economic engine." The group leads the effort to build a 5-acre park on the eight-lane Woodall Rodgers Freeway that runs north of downtown, between U.S. 75 and Interstate 35E. Traffic will be channeled to a tunnel. It's part of a bigger plan to revitalize the city's core and connect all corners of a 68-acre cultural district, from museums, restaurants and residential towers to a new opera hall and performing arts center. "The freeway is like our medieval wall," Owen says. "You couldn't get over it. … The park is just being created out of thin air." Similar projects are under review in: • Los Angeles and Santa Monica, Calif. There are four proposals to "cap" obsolete sections of the 101 or Hollywood Freeway — in Hollywood and downtown Los Angeles — and I-10 in Santa Monica with parks and developments that mix residential, retail and office uses. The area's density makes it difficult to create parkland, but old freeways offer vast spaces that can be used, says Vaughan Davies, the architect and urban designer leading some of the efforts. "The one in downtown Los Angeles encompasses 100 acres of land and the park itself is about 15 to 20 acres," he says. It would connect Union Station, Chinatown and Olvera Street with City Hall and Little Tokyo. Another plan would bring a park and school on 40 acres over the Hollywood Freeway through a largely residential area. In Santa Monica, an old section of I-10 would link the area near the Santa Monica Pier with the civic center. • Cincinnati. In a city that has more expressway interchanges per mile than most cities, freeways cut off the downtown from its riverfront near the confluence of I-75 and I-71. "We need to reconnect downtown to the river," says Michael Moore, interim director of transportation and engineering. Several exits were consolidated to create Fort Washington Way, opening about 16 acres of unused space for development and 40 acres for a park on the banks of the Ohio River. • St. Louis. A design competition is underway to connect the Gateway Arch grounds and downtown over I-70, which divides the two. A non-profit citizen group, City to River, proposes removing a section of the interstate that is not needed since traffic has been shifted to a new bridge north of the Arch. Turning it into a 1.4-mile boulevard and parkway would "create more valuable real estate, close to the Arch," says Rick Bonasch, a member. "This boulevard would connect downtown casinos, hotels, sports stadiums and the historic riverfront." The projects face relatively little opposition, Harnik says. "The green movement wants more parkland, and the development community wants a beautiful, quiet park instead of a noisy freeway to build residential or office buildings around them," he says. "The payback in … economic value is high enough to make the whole thing worthwhile." Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. 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