Aug 28, 2023 - Development

Building a lid to support a park over I-5 gains traction

One preliminary idea for what an I-5 lid could look like. Rendering courtesy of the Lid I-5 Steering Committee

An idea to connect downtown Seattle with Capitol Hill with a "lid" that could support a large park over Interstate 5 is gaining momentum, with city officials eyeing new federal grant money intended to undo divisions caused by freeways.

Why it matters: Supporters of creating the seamless overpass say it would open up 11 or more acres downtown that could be used for public parks and affordable housing, while helping erase the scar the freeway cut through downtown neighborhoods when it was built in the 1960s.

What's happening: The Seattle City Council is expected to vote Sept. 5 on a resolution formally declaring the city's support for the project and directing city departments to work with state and federal officials to try to make it happen.

  • Those efforts would include applying for federal grants, potentially as soon as next month.

What they're saying: "What is currently the air above these concrete canyons that are just used for vehicles to pass through the heart of our city could be space that is used to reunite the community," City Councilmember Andrew Lewis, the sponsor of the council resolution, said at a committee meeting earlier this month.

  • The lid could reduce pollution and road noise in neighborhoods along the freeway, areas that are mixed income and "very racially diverse," Scott Bonjukian, co-chair of the Lid I-5 Steering Committee, told Axios.
  • "My vision is you could walk from Capitol Hill to downtown and you don't even realize you crossed neighborhood boundaries, and there's a seamless experience," said Bonjukian, whose community group has been promoting the idea for years.
  • He cited the potential for more pedestrian walkways and bike lanes, plus open spaces where people could sit outside and enjoy takeout from a nearby restaurant.

Plus: A lid could also add space for commercial development, including restaurants and storefronts, in an area of the city where there's little land left to build on, Bonjukian said.

Details: A feasibility study completed in 2020 determined that creating street-level connections over I-5 between Madison Street and Denny Way would be possible.

Yes, but: Naturally, it would cost money — between roughly $1 billion and $2.5 billion, according to estimates from the 2020 study.

  • The amount of investment would depend partly on whether the city wants to build solely park space on top of the lid, or also build a structure that can support buildings, which would cost more.

The big picture: State officials are on board with exploring an I-5 lid as part of the master planning process for the highway, which is in need of other fixes, such as earthquake upgrades, state Sen. Marko Liias (D-Everett) told Axios.

  • That planning process is likely to take several years, he said.
  • Other U.S. cities, including Phoenix, St. Louis and Dallas, have also built parks over freeways in recent years.

What's next: After the council votes, Seattle officials want to start going after federal grants, some of which have application deadlines by the end of September.


Get more local stories in your inbox with Axios Seattle.


Support local journalism by becoming a member.

Learn more

More Seattle stories

No stories could be found


Get a free daily digest of the most important news in your backyard with Axios Seattle.


Support local journalism by becoming a member.

Learn more