A constant roar rises from Interstate 94 in St. Paul as cars rip down eight lanes of traffic on their way between the Twin Cities’ two downtowns. What sliced apart a thriving neighborhood a half-century ago is a stark, concrete reminder of how freeways can disfigure cities.

Still, the Rondo neighborhood has retained its hold on St. Paul’s collective memory. Now a diverse group is pursuing an ambitious idea for knitting Rondo back together by covering up a portion of the freeway with a structure known as a “land bridge” or “freeway lid.”

What began about two years ago as a neighborhood group’s pie-in-the-sky idea is gaining momentum, with backing from the city, Ramsey County, the Minnesota Department of Transportation, the University of Minnesota and Mayor Melvin Carter, who grew up in post-I-94 Rondo.

“This is an idea that’s time has come,” said Lyneir Richardson, who chaired an Urban Land Institute (ULI) panel that studied the Rondo land bridge idea. “This is a vision that can be achieved.”

The seven-member panel visited St. Paul last week to spend time in Rondo, interview community members and make a recommendation for moving forward with a land bridge over I-94. In a presentation Friday morning at the Hallie Q. Brown Community Center, panel members told the crowd of about 100 people that the project could be a national model.

The panel recommended that MnDOT construct and maintain a 5-block bridge, that black residents have a say in every aspect of the project and that ReConnect Rondo, the nonprofit leading the project, work with MnDOT to secure $6 million for planning efforts over the next one to two years.

Depending on how many blocks it spans and what is built on top of it, the land bridge could cost up to a billion dollars.

ULI is a nonprofit research group that convenes authorities on real estate and land use to advise on complex planning projects. The panel will issue its final recommendations in the next two months.

After Friday’s presentation, MnDOT Commissioner Charlie Zelle said the agency is committed to the project.

“It’s going to be a very collaborative process,” he said.

Beginning in the 1950s, construction of Interstates 94 and 35 tore apart neighborhoods throughout St. Paul and Minneapolis. None has been mourned as much as Rondo.

The predominantly black neighborhood dates back to the late 19th century, and for decades it was a thriving middle-class community. When I-94 was built, it split Rondo in half, taking with it nearly 1,000 homes and businesses.

At a community meeting about the land bridge in January, Carter told attendees that his grandfather lost several commercial properties.

“I inherited the deeds that aren’t worth the paper they’re printed on,” he said.

It’s not yet clear what the land bridge would look like or how much it would change the existing landscape. No matter what form it takes, the goal is to start repairing some of the damage the freeway inflicted.

Rondo residents have said they’d like to see the freeway cap covered with parkland, local businesses, affordable housing and other amenities. The ULI panel recommended starting with a bridge covering I-94 for the five blocks between Chatsworth and Grotto streets, with potential to expand.

Preliminary renderings from the U’s Minnesota Design Center unveiled in January show possible designs ranging from development along the state-owned land on either side of the freeway to a 5-block lid with buildings, streets and green space.

Tom Fisher, the center’s director, said buildings incorporated into the bridge design would be constructed on the land that lines the freeway, rather than over lanes of traffic. The area over the freeway itself would be green space.

“People don’t realize how much land actually exists on the embankments of these highways,” Fisher said. “It’s actually not as complicated as it may seem.”

The Twin Cities already have one land bridge, built in 2003 over Hiawatha Avenue in Minneapolis. In Duluth, multiple land bridges stretch across I-35.

Early this year, ReConnect Rondo staff traveled to Texas to visit the 5-acre Klyde Warren Park, built over Hwy. Spur 366 in downtown Dallas. The $110 million land bridge, funded with city, state and federal dollars and private donations, opened to the public in 2012 and offers events and activities such as movie nights, concerts and exercise classes.

OJB Landscape Architecture, the firm that designed the park, is now working on a second Dallas land bridge and another in Kansas City, Mo. Jim Burnett, the firm’s president, said “there always is skepticism” around land bridge projects, in part because they’re expensive to build.

“The way we got around it [in Dallas] was the idea that the land was free,” Burnett said.

Through a long-term agreement with the Texas Department of Transportation to put a lid on the freeway, he said, the park was built on 5.2 acres that now are worth tens of millions of dollars. The park has reportedly spurred more than $1 billion in new development.

Margaret Lovejoy, a Rondo resident, attended the presentation Friday and said she wants to visit land bridges in other cities. She was a child when I-94 came through, and though her family home wasn’t affected then, it was torn down years later as part of an urban renewal effort.

Lovejoy said she’s glad planners want to hear from the community before making decisions on the land bridge — unlike when the freeway was built. Above all, she said, she wants green space on the bridge, and to put a lid on the freeway noise.

“I’m excited about the potential,” she said.