Full Breakdown
Overlapping Road Closures Set to Stall Puget Sound Traffic This Weekend
By Drooid · · How we work
Background & Context
The Washington State Department of Transportation (WSDOT) has scheduled construction and maintenance projects from Friday night through Monday morning across the greater Puget Sound region. Projects include drainage upgrades beneath the I-5 Ship Canal Bridge, removal of an old off-ramp on Highway 520, routine inspections on the Aurora Bridge, paving work on I-405 in Tukwila and Kirkland, and overnight maintenance in the Highway 99 tunnel. The timing clusters these jobs to address a backlog of work lost during the summer World Cup and to prepare for the rainy season.
Core Event: Multiple Closures Create Major Bottlenecks
- I-5 Express Lanes (northbound) – Closed from Friday night until Monday morning to replace drainage under the Ship Canal Bridge.
- Eastbound Highway 520 (I-5 to Montlake Blvd.) – Closed for the same period while the old off-ramp and viaduct sections are removed.
- I-405 Southbound (Tukwila) – Up to two lanes shut from Saturday evening to Sunday afternoon for paving.
- I-405/Northeast 85th St Interchange (Kirkland) – All on- and off-ramps close from Friday night through Monday morning for street paving and BRT station construction.
- Highway 99 Aurora Bridge – Two southbound lanes close Saturday morning; northbound lanes close Sunday morning, each for a few-hour inspection.
- Highway 99 Tunnel – Closed overnight Friday to Saturday for routine maintenance.
These closures compress traffic onto the remaining open lanes, especially on the northbound I-5 deck where only two lanes will be available across the Ship Canal Bridge.
Data & Statistics
- Lane reductions: Up to two lanes on I-405, two lanes on I-5 northbound, and two lanes on the Aurora Bridge.
- Duration: Most closures span roughly 30-hour windows; Aurora Bridge lane reductions are limited to six-hour periods each day.
- Geographic impact: Affects routes serving Seattle-Tacoma International Airport, commuters between Seattle and the Eastside, and travelers heading to the Pacific coast via Highway 101.
Official Statements & Responses
WSDOT spokesperson Tom Pearce emphasized that the drainage upgrades on the Ship Canal Bridge are intended to reduce water-related road hazards during the rainy season. A project spokesperson noted that the I-405 work is part of a larger widening and express toll lane initiative designed to improve long-term capacity.
Why It Matters
The overlapping closures compress high-volume traffic onto a reduced lane network during peak commuting hours, extending travel times and increasing congestion on alternate routes. The projects aim to address long-standing infrastructure deficiencies—particularly drainage on the I-5 bridge and aging components on Highway 520—but the short-term trade-off is a regional slowdown that could affect airport access and freight movement.
What’s Next
WSDOT has indicated that after the weekend closures, the I-5 drainage work will be completed, and the removed Highway 520 off-ramp will be replaced with a new concrete bridge over Portage Bay. Additional paving and widening projects on I-405 will continue in the weeks following the weekend, with further lane reductions expected as each phase progresses.