Collaborative to Unveil Latest Lid I-5 Designs Tonight

A conceptual 3D model for lidding I-5 north of Denny Way. Credit: Central Hills Triangle Collaborative

After months of grassroots effort and volunteer engagement, The Central Hills Triangle Collaborative (CHTC) will present its conceptual designs for lidding I-5 in central Seattle tonight (October 3) at 5:30 PM, at Melrose Market Studios. The event is free and open to the public. RSVP here.

The lid designs are the culmination of a series of Collaboratives sponsored by Lid I-5 Steering Committee and the Pike/Pine Urban Neighborhood Council (PPUNC). Kicked off by a charrette at 12th Avenue Arts last March, the sessions were funded by a $48,000 Seattle Department of Neighborhoods Neighborhood Matching Fund grant and fiscal sponsorship from the Seattle Parks Foundation. All events have invited the public to provide ideas and feedback.

The lid study area runs Downtown between Madison Street and Thomas Street, representing approximately 15 acres of developable airspace above the freeway. Each of the five design teams was assigned a subarea and received assistance from an overarching Connections team that provided guidance on pedestrian and bicycle mobility, as well as what potential utility infrastructure the lids could support.

Design teams included volunteer professionals such as architects, landscape architects, urban planners, and engineers, as well as community members representing a variety of interests.

The conceptual designs present options for increasing affordable housing, expanding public open space, and supporting community facilities like schools.  As a whole, new developable space created by the lids has the potential to serve a diverse array of public and private functions.

Participants at the CHTC Kickoff Charrette in January 2018. (Credit: Central Hills Triangle Collaborative)

High profile guest speakers at tonight’s event include Seattle City Councilmember Sally Bagshaw, Seattle Office of Planning and Community Development (OPCD) Director Sam Assefa, and Seattle Parks Foundation Executive Director Thatcher Bailey.

This event comes at an important moment in the Lid I-5 campaign. By the end of 2018 Seattle OPCD will release a request for proposals to comprehensively study the engineering, economic, and urban design aspects of lidding I-5. The $1.5 million study, funded by the Washington State Convention Center, was approved by Seattle City Council and will take one year to complete.

Lid I-5 revealed this image as teaser for their October event.

The momentum for lidding I-5 comes at a time in which an increasing number of metro areas across the US are looking toward a future in which neighborhoods that were ripped apart by the construction of freeways can restore connections by lidding freeways.  

In California, a state synonymous with freeway construction, freeway lids are being proposed and built in cities such as San Francisco, Los Angeles, and Santa Monica.

Given the significant amount of air and noise pollution created by freeways, it is not surprising that cities with high land values and limited developable land, such as Seattle, are reconsidering the role of the freeway in the city’s urban fabric.

“If we take this innovative opportunity suggested by the Lid I-5 campaign, we could have 20 acres of new public land Downtown,” wrote councilmember Sally Bagshaw on her City website. “Land costs are rising as buildable sites diminish. Lidding provides us with a tried-and-true way to create new public space while reducing the noise and pollution which spills into neighborhoods.”

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Natalie Bicknell Argerious (she/her) is Managing Editor at The Urbanist. A passionate urban explorer since childhood, she loves learning how to make cities more inclusive, vibrant, and environmentally resilient. You can often find her wandering around Seattle's Central District and Capitol Hill with her dogs and cat. Email her at natalie [at] theurbanist [dot] org.

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Steve Corley

I think the lidding idea is missing the opportunity to really address the wound that I-5 is to Seattle. Given the coming need to rebuild large portions of the freeway, take a leap and reconnect the grid. Rethink that right of way. Two level roadway: The lower level rebuilt as a limited access I-5 (say, 6 lanes, 3 each direction) that runs with zero (or max two) entry/exits between I-90 and 145th. Above, a wide boulevard at grade with similar number of vehicle lanes including a dedicated transit lane each direction, along with a very wide center walk/bike path. This boulevard would also connect all the E/W streets that can be practically connected along the way. The ROW would be narrower than that of the current I-5 and the remaining space could be sold for development (tax base!) as well as include frequent park sections. This is a dream, yes. But that ROW should serve citizens of Seattle by generating more tax revenue, adding to housing stock, improving livability and improving connections all along the way.

Brian Nelson

Also, traveling east/west in this city is ridiculous. If WSDOT ever does plan to lid I5 I’d be a huge proponent of them connecting Thomas to E Thomas. This would give busses and drivers another road to move from one side of the city to the other, relieving some of that nasty traffic on Denny.

Mike Carr

I don’t think their are plans to put roads on the lid, kind of defeats the purpose.

Brian Nelson

Roads on lids are actually quite common, see the the 520 lids and the Mercer Island I-90 lid as great examples! Any lid that WSDOT would put in along this proposed stretch will already need to include roads for Madison, Spring, Seneca, Pike, Pine, Olive, and Denny… Wouldn’t hurt to put in another true E-W connection along Thomas.

Brian Nelson

Ugh, this upcoming $1.5m study is going to be such a waste money. What’s the over/under that a lid, as imagined in the image above, costs more than $1bn in public funds?


A back of the envelope calculation using appraised land value for adjacent parcels indicates this will create over $600 million in land value (although I’d love to see a real analysis). That doesn’t even include the buildings that are in this design. That, in combination with the vast improvement for the public, seems totally worth it.