Senator Liias talks plans to ‘lid’ I-5 as maintenance continues

The movement to lid I-5 between Madison and Denny has been floating around social circles of transportation junkies and public works fans for years now, but now has a big public name advocating for it; Washington State Senator and chair of the transportation committee Marko Liias.

Liias spoke to Dave Ross on Seattle Morning News about the project brought forward by the community group Lid I-5.

Supporters optimistic for ‘pie-in-the-sky’ idea to lid I-5 in Seattle

The project aims to cover, or “lid,” stretches of I-5 to expand space for urban development, address the city’s housing crisis, reduce traffic noise, and beautify the city.

While lidding is just one of the many proposals to handle, it would be a big investment in the area along with other big infrastructure investments Liias plans to make in his Move Ahead Washington bill.

The project itself has multiple different models proposed if it gets enough community support.

“I think it would probably look more like what we see over I-90 in the sort of Judkins Park area, or what we see at Mercer Island, where ideally the highway would just be out of view,” Liias said.

One of the biggest reasons for rehauling I-5 though is the seismic protections against earthquakes need to be updated.

“It’s a structure, essentially a bridge from the 1960s that runs through downtown Seattle, it doesn’t meet today’s seismic needs, we know that it would be vulnerable in an earthquake, and traffic is terrible on I-5 at peak hours through downtown.”

For now, a $1.5 million feasibility study is being conducted to determine whether an I-5 lid is even possible. If it is, the hope is that similar projects could work throughout the city. Working on the I-5 lid feasibility project is WSP, “a global engineering firm with extensive local experience,” selected by the city of Seattle in 2019, and still developing a plan for what it might look like.

The earliest we will likely see work done on this kind of project Liias says is the end of the decade, but “the planning, the conversation, the imagining is starting now so it’s really important to figure out what’s on the table, what’s not on the table.”