Architecture firm EHDD is helping mayors and city planners nationwide to create highway lids, or public spaces on top of highways.

While not new, highway lids—also known as cut-and-cover tunnels or freeway tops, decking, or caps—are newly resurgent, according to a statement from EHDD. Highway lids are now widely seen as a way to spark community engagement, tourism, and investment, EHDD says.

Seventy years after the U.S. Interstate program began, there are now over 400 lidding projects underway.

In San Francisco, the EHDD-designed Presidio Tunnel Top, which opened in 2022, replaced an elevated highway viaduct with cut-and-cover tunnels. This year, the 18-acre, $118 million project won the Urban Land Institute (ULI) Americas Award for Excellence.

The project team on the Presidio Tunnel Tops included landscape architect Field Operations,  civil engineer MKA, structural engineer Holmes Structures, MEP engineer PAE Engineers, and general contractor Swinerton. 

“Hundreds of these wide bridge structures built over roadways, which block noise and hide traffic under revived neighborhoods with new urban spaces and parklands, plus more housing, are now in planning or construction,” Christopher Patano, EHDD principal and partner, said in the statement.

“We’ve championed freeway tops in various forms,” Patano continued, “and while we’re realistic about the costs and political challenges, their merits are enduring: addressing the damage freeway cuts have done to many neighborhoods and adding valuable developable land, public amenities, and attractions, all while maintaining highway capacity.”

Other highway lid projects include the following: 

• In Dallas, Klyde Warren Park, a $110 million, 5-acre cap that opened in 2012, bridges the city’s Downtown and Uptown neighborhoods. Dallas is now planning a $122 million, 1.7-acre expansion of Klyde Warren Park. 
• In Pittsburgh, Frankie Pace Park is a $32 million, 3-acre cap over I-579 that opened in 2021. 
• In Sacramento, a proposed $3 million, 4-acre park over I-5 will reconnect downtown and the waterfront. 
• In Seattle, efforts are underway to lid portions of I-5, currently backed by $2.2 million in funding for expanded feasibility studies. 
• In St. Louis, a $33.6 million, 0.6-acre cap, which opened in 2015, created a pedestrian land bridge between the Gateway Arch and downtown.