State and county outline multi‑year plan to rebuild I‑5/179th interchange with roundabouts, bridges and shared paths

WADOT representatives told the Fort Creek Neighborhood Association that the I‑5/179th interchange project is primarily a mobility and safety effort that would replace two existing traffic signals with roundabouts, replace two bridge spans, raise I‑5 by approximately four to five feet, and add shared‑use paths and new drainage and lighting.

"The goal of the project is to improve safety and mobility at this interchange by replacing the two existing signals with roundabouts," said Sarah Hannah Nine, communications lead for the WADOT Southwest Region, summarizing the agency's design intent. She said roundabouts reduce the most serious crashes, allow continuous traffic flow, and can be designed with truck aprons so freight can navigate the circles.

WADOT described a multi‑phase schedule the agency and its partners presented to the neighborhood: preliminary design began in 2025, the project team expects to complete design and environmental review steps in the coming years, advertise the contract in 2028 and begin construction in 2029 with completion targeted around 2031. Sarah said noise and other environmental effects "will be evaluated during that environmental review process," and that the review is the point at which the need for mitigation such as a sound wall would be determined.

County staff added that some work is already under way nearby and that construction will be staged to maintain local access where possible. The county engineering team said bridge work is planned for summer construction windows when creek flows are lower and that several lane and intersection closures will be needed during staging; residents were advised to expect rolling changes to access and temporary detours.

Residents raised event‑traffic and noise concerns tied to Cascad's Amphitheater and other destinations near the interchange. WADOT and county staff said they are coordinating with amphitheater and fairgrounds personnel on signage and event plans, and that messaging to stagger arrival and departure times is part of the strategy to reduce peak congestion.

Attendees also questioned pedestrian and emergency‑vehicle operation in roundabouts. WADOT said the design includes refuge islands and marked crossings at roundabout legs and that emergency vehicles can navigate roundabouts; the project will include shared‑use paths and crossings intended for people walking and biking.

WADOT representatives and county engineers said the project will require some property acquisitions to accommodate the roundabouts and wider footprint. Cost and schedule risks remain until final design is complete, the agencies said; funding is committed for design and later stages, but final construction costs will be clearer when bids are solicited.

The project team said it will hold another open house later this year to show more detailed design materials and to take public comment as the environmental review and design progress.

What happens next: WADOT and Clark County expect to post project materials and email notifications for an open‑house update later this year; design details and environmental review findings will precede any decision on noise mitigation or property acquisitions.