A coalition of Minneapolis leaders believe the freeway snaking through the city's core should be buried alive.

Across the country, cities are covering loud highway trenches with lids, or caps, that block out noise, restore old neighborhood connections and yield development opportunities.

In Minneapolis, planners have their eye on covering a portion of Interstate 35W that separates Downtown East and Cedar-Riverside neighborhoods, running from Washington Avenue S. to about 5th Street.

A lid over that gap would create 17 acres of green space above the highway and the chance to put up new buildings on both sides.

Still in the early concept stages, the project team has yet to nail down a cost estimate or get a funding proposal in place, but they say the payout will be greater than the risk. Already, a challenge is emerging: gaining the support of residents in Cedar-Riverside.

The first step is to look at the successes and failures of lidding projects elsewhere, said Charles Zelle, commissioner of the Minnesota Department of Transportation, which, as the primary landowner, would take the lead role on the project.

"When you think about capturing both park and revenue-generating space, it becomes very interesting," Zelle said. "We want to be careful in our planning but we don't want to be closed to new ideas."

San Diego, Seattle and Columbus, Ohio, have all put lids over highways. Chicago's Millennium Park is a 24.5-acre lid over sunken railroad tracks.

St. Louis is building a park over Interstate 44 by the Gateway Arch, and Los Angeles is mapping out a lid project over Hwy. 101 downtown. Denver is embroiled in a fight over putting a lid on a portion of Interstate 70, though opposition is centered on the widening of the already-expansive freeway to be covered.

Dallas connected a museum district by building a 5.2-acre park over a recessed eight-lane freeway, using both public and private funds. "What they did in Dallas is extraordinary," said Jacob Frey, the Minneapolis City Council member who represents the downtown area. "That project is literally paying for itself in property tax revenue."

Minnesotans may be familiar with Duluth's Leif Erickson Park, which sits atop an I-35 tunnel that was built using a cut-and-cover technique. And Edina is exploring a lid over Hwy. 100 at W. 50th Street.

"We are really at step one out of a dozen or a hundred different steps," said Bill Neuendorf, Edina's economic development manager. "It's an exciting concept, and we will look and see if this thing has legs to go somewhere."

The project in Minneapolis has been aided by concepts developed at the University of Minnesota's Metropolitan Design Center.

"By developing the air rights above highways in areas of high demand, we can generate revenue that can help us repair our state's roads and other infrastructure," said Tom Fisher, dean of the College of Design at the U. "We also wanted to show what a family-friendly neighborhood in the city might be like, with child-safe playspace separated from traffic."

The lid trend is also shaped by planners who are attempting to fix systems developed in the past that are now perceived as misguided. When transportation goals in the 1950s and '60s sought to move people faster and farther, interstates and highways carved up cities and severed neighborhoods in the process.

"Now, more and more, because urban land is more valuable and because people have a different take on how cities should function and a better understanding of how these things are harmful, there's a broad trend in cities to try and heal some of the rifts created," said Rachel MacCleery, senior vice president at the Urban Land Institute in Washington, D.C.

While many cities put green space atop highway lids, anything can be tried, MacCleery added. "Every city's situation is unique, and what makes sense from a land-use perspective will, in many cases, be buildings," she said. "There were things that were there before these highways came through, and it might make sense for these uses to return."

Forging a connection to the U is one of 10 goals outlined in Minneapolis Downtown Council's 2025 Plan, which also suggests "green corridors over the Interstate 35W freeway trench." After U students made models of the I-35W lid earlier this year, MnDOT staffers plunged into research on the concept.

Fourteen parcels of underused land at the site could be developed and bolster the tax base without tearing down any existing buildings, said Mic Johnson, interim director of the Design Center.

In an estimate that assumes 14 residential, retail and office buildings could fit on the parcels, the real estate firm Jones Lang LaSalle found construction would generate $57 million in initial tax revenue and the completed project would yield about $28.8 million in property taxes annually.

"Of the 14 parcels that they designed, 10 are not on the tax rolls because they are owned either by MnDOT or the county," said Ann Marie Woessner-Collins, managing director of JLL's business and economic incentives.

Supporters also say that linking downtown and Cedar-Riverside would pay off in greater livability for residents on both sides. As the Mill District continues to expand and the new Vikings stadium is built, the east side of downtown has become a focus for developers.

Some in Cedar-Riverside worry that the new connection could spur a gentrification wave that would outprice current residents.

"This is the largest bank of affordable housing that we have left in the city," said A.J. Siddiqui, president of the West Bank Community Coalition. "Ultimately, with this connection, the rental prices and property taxes are going to go up."

Just over half of the neighborhood's residents live below the poverty line, compared with 22.5 percent for Minneapolis as a whole, according to the American Community Survey's five-year average for 2008-2012. The densely populated neighborhood — 15,500 residents per square mile — has a median household income of about $13,500, while Minneapolis overall is $48,800.

"People here like how it is. If we connect to the downtown, it is bound to change the texture of this neighborhood," Siddiqui said.

He said the neighborhood needs more park space, however. "We have one tiny park, and I don't think there is any park in all of Minneapolis that is so packed with women, younger kids, older people there all the time," he said.

"I think that if there is some proposal that they can keep this area's affordable housing and still accomplish the goal, then I can be in support," Siddiqui said.

Frey said the concerns in Cedar-Riverside will "need to be thoughtfully approached" if the lid is to receive widespread support.

Once people get comfortable with the idea and the vision solidifies, funding will be the next barrier. "It is going to take the public sector and private sector holding hands and proclaiming this is worth it all at once," Frey said.

Zelle suggested the cost of the lid may force MnDOT, which is used to financing and managing highway projects on its own, to open itself to collaboration. "We aren't going to be the clunky agency resisting change," he said.

Kristen Leigh Painter • 612-673-4767