Many projects this summer will help bring improvements to state highways in King, Snohomish counties

People should plan ahead for recreational travel or daily commute

SEATTLE – With projects affecting all of the region’s major freeways this summer – as well as many projects on smaller state highways – people need to plan ahead for travel, whether it’s the everyday commute or the big summer road trip.

The Washington State Department of Transportation has many projects scheduled during the summer construction season, including:

  • Several fish passage projects, most notably on Interstate 90 just east of I-405 in Bellevue.
  • The I-405 southbound express toll lanes between Renton and Bellevue.
  • The State Route 520/I-5 connector project in Seattle.
  • Work to complete the SR 509 expressway all the way to I-5 in SeaTac.

Messay Shiferaw, WSDOT’s assistant regional administrator for construction in King and Snohomish counties, said in addition to these projects, there will be a considerable amount of other preservation projects to repair numerous state highways.

“People will be able to get to their destination this summer, but we highly encourage them to stay engaged and plan ahead,” Shiferaw said. “We have a lot of work planned on all of the major freeways as well as other highways throughout the region. Planning ahead will make it easier and safer for people to get to their destination, whether it’s vacation, a special event or an everyday commute.”

Some of the projects that will be most noticeable to people this summer include:

I-90 fish passage

Sunset Creek in Bellevue goes through a culvert about 100 feet below I-90 east of I-405 near the Eastgate area. This culvert keeps salmon and other fish from traveling upstream and must be replaced. This summer WSDOT begins a four-year project to build bridges for both directions of I-90 as well as Eastgate Way and Southeast 36th Street. The work will require lane shifts and lane reductions at various times throughout the project, which is scheduled through 2027.

I-405 express toll lanes

Between Renton and Bellevue, this project will widen I-405 and create express toll lanes in both directions to make a 40-mile ETL system, including HOT lanes on SR 167, between south King County and Lynnwood and builds critical infrastructure for Sound Transit’s Stride Bus Rapid Transit system. The work generally includes adding one lane in each direction of I-405, provide room for two express toll lanes in each direction. We anticipate up to four weekends of closures and lane reductions of I-405 this summer, starting with two consecutive weekends of lane reductions for paving June 2-5 and June 9-12. This work is scheduled to be completed in summer 2025.

SR 520/I-5

The west end of the SR 520 corridor is busy this summer with two major projects:

  • The Montlake Project replaces the old, structurally vulnerable eastbound bridge over Union Bay and adds a dedicated HOV/transit lane. This project also builds a three-acre, landscaped lid over the highway in Montlake and, east of the lid, a bicycle and pedestrian land bridge over the freeway.
  • The I-5 Express Lanes Connection Project adds a dedicated reversible transit and carpool connection between SR 520 and the I-5 express lanes, as well as a reversible transit/carpool lane at the I-5/Mercer Street interchange.

Both projects are slated to have several weekend and extended closures all summer including an 18-day closure of the westbound SR 520 off-ramp to East Roanoke Street that started yesterday.

SR 509 completion

When complete, this project will extend the SR 509 freeway from its current end point at the southwest corner of Seattle-Tacoma International Airport to I-5 in the city of SeaTac. This includes building a new flyover ramp to connect SR 509 and I-5, widening the South 216th Street bridge over I-5 and improvements to the SR 516/I-5 interchange in Kent. When complete, the new expressway will provide a north-south alternative to I-5 for people and commercial traffic traveling between Seattle and South King County.

These are just some of the projects people will see on the region’s highways. To learn about construction on any state highway, WSDOT has complete information available on its website.

Any time people encounter a work zone on a freeway or other state highway, they should stay alert and minimize distractions, obey posted speed reductions, avoid tailgating and follow instructions of flaggers.

People who are traveling can get real-time traffic information on mobile phones with the WSDOT traffic app and by following the WSDOT traffic Twitter feed.

Slow down – lives are on the line. 

In 2023, speeding continued to be a top reason for work zone crashes.

Even one life lost is too many.

Fatal work zone crashes doubled in 2023 - Washington had 10 fatal work zone crashes on state roads.

It's in EVERYONE’S best interest.

95% of people hurt in work zones are drivers, their passengers or passing pedestrians, not just our road crews.