A full closure of I-405 will make for a rough weekend commute

Commuters need to plan ahead this weekend if traveling through Seattle.

The Washington State Department of Transportation (WSDOT) has scheduled a full closure of northbound I-405 between Renton and Bellevue. This will send most of that traffic to I-5 through downtown Seattle.

Don’t forget WSDOT has two lanes closed on the Ship Canal Bridge for their Revive I-5 Project, with this phase continuing to the end of 2026.

Over the weekend, crews will work on drainage, repaving, and a traffic switch as part of the I-405/Renton to Bellevue Widening and Express Toll Lanes Project. Also, overnight lane closures are scheduled on northbound I-405 between Kirkland and Bothell, Sept. 19-20, for a traffic shift as part of the I-405/Brickyard to SR 527 Improvement Project.

Northbound I-405 full closure from Renton to Bellevue

Northbound I-405 will close between Northeast Sunset Drive/SR 900 and Coal Creek Parkway Southeast from 11:30 p.m. Friday to 4 a.m. Monday.

The following ramps will also close.

• N Southport Drive on-ramp to northbound I-405.
• N 30th St. on-/off-ramps (Exit 6).
• NE 44th St. on-/off-ramps (Exit 7).
• 112th Ave. SE on-/off-ramps (Exit 9).
• Northbound I-405 off-ramp to Coal Creek Parkway SE (Exit 10).

A northbound detour will be in place. Travelers are advised of northbound lane reductions on Coal Creek Parkway Southeast as part of the Coal Creek Sewer Upgrade Project that will cause delays along the detour route.

Overnight northbound I-405 lane closures from Kirkland to Bothell

Northbound I-405 will have lane closures and rolling slowdowns overnight from Kirkland to Bothell.

Up to three lanes will close from NE 128th St. to SR 522 from 11 p.m. Saturday to 7 a.m. Sunday.

Crews will implement a rolling slowdown between 12:01 a.m. and 3:30 a.m. Sunday.

Eastbound I-90 reducing to one lane in Bellevue

Eastbound I-90 will reduce to one lane from Friday night to Sunday afternoon, near the I-405 interchange in Bellevue, for paving and repairs to the freeway bridge crossing over Richards Road.

Closures will be in place from 8 p.m. Friday to 2 p.m. Sunday.

• Three left lanes of eastbound I-90 near the I-405 interchange.
• Eastbound I-90 HOV off-ramp to Bellevue Way Southeast.

Lane reductions will begin on Mercer Island and build to three left lane closures at Richards Road. At least one lane of eastbound I-90 will remain open throughout the weekend.

SR 520 eastbound lane closures at West Lake Sammamish Parkway Northeast

Two right lanes of eastbound SR 520 at West Lake Sammamish Parkway Northeast (milepost 11) will close from 8 a.m. to 4 p.m. on Saturday.

These lane closures will allow WSDOT crews to safely perform bridge deck repairs.

Drivers should expect delays.

I-5/I-405 overnight ramp closure in Lynnwood

Commuters in Lynnwood will see an overnight ramp closure at the I-5/I-405 interchange on Sunday.

Crews will close the southbound I-5 ramp to southbound I-405 from 10 p.m. Sunday to 4 a.m. Monday.

WSDOT crews will complete final striping as part of the SR 525/I-405 Interchange to SR 99 Vicinity – Paving & ADA project.

This project repaved roughly 2 miles of SR 525 in both directions from the I-405 interchange to just south of 148th Street Southwest. It also placed a new layer of asphalt on eight ramps in the area.

I-5 lane closure at Ebey Slough

Travelers on I-5 in Marysville should expect lane closures on Saturday and Sunday for bridge maintenance and inspections.

From 5:30 to 10:30 a.m. on Saturday, the left lane of northbound I-5 over the Ebey Slough at SR 529 (milepost 198) will close.

From 5:30 to 11:30 a.m. on Sunday, the right lane of southbound I-5 over the Ebey Slough at SR 529 will close.

Drivers should plan for delays.

Weekend ramp closure at SR 7/SR 512 in Parkland

From 8 p.m. Friday to 8 a.m. Sunday, the SR 7 ramp to eastbound SR 512 will close to all travelers.

During the closure, travelers will need to use alternate routes.

This weekend ramp closure will allow crews to extend a Parkland area on-ramp onto SR 512.

Contractors will add 840 feet to the ramp’s merge lane. That is more than two football fields. The added distance will help improve traffic flow for travelers both using and entering the highway.

Crews will also add new lighting and traffic loops later in the project. Traffic loops detect congestion on state highways. The loops will connect to ramp meters, which help control the flow of traffic entering the highway and reduce merging issues.

Data sensor installation

The $1 million project also includes the installation of a new Wavetronix data sensor along SR 512 near the I-5 interchange.

The sensor will collect information about traffic volumes. The data will help with work zone planning, traffic analysis, and future corridor management.

The sensor uses radar to collect information and does not have a camera.

WSDOT expects to complete work by the end of November.

Weekend alternating traffic on SR 203 

On SR 203 at Riley Slough near Monroe, traffic will alternate from Friday night to Monday morning for a paving project.

WSDOT crews will repair the bridge deck at Riley Slough (milepost 22) near Monroe from 8 p.m. Friday to 6 a.m. Monday.

Flaggers and pilot vehicles will alternate northbound and southbound traffic through the remaining open lane. This work is dependent on dry weather and may need to be rescheduled if rain is forecast.

A second weekend of single-lane closures for bridge repairs at Riley Slough will be announced once the dates are finalized.

The highway was last paved in 2008, exceeding its 15-year life expectancy. This project is essential to maintain the road’s integrity and ensure long-term safety for all travelers.

Nate Connors is a traffic reporter for KIRO Newsradio. Follow him on X. Read more of his stories here. Submit news tips here.

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