Infrastructure

I-405, I-5, SR 99 closures for work

Friday, August 28, 2026

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I-405, I-5, and SR 99 will have multiple lane closures starting this week for construction and utility projects, according to Washington State Department of Transportation (WSDOT) updates.

Northbound I-405 will close all lanes from Northeast 70th Place to Northeast 85th Street from 11 p.m. Friday, Aug. 28, to 5 a.m. Monday, Aug. 31, with a detour in place. Southbound I-405 will lose up to two lanes from milepost 12 to Coal Creek Parkway Southeast from 9 p.m. Thursday, Sept. 3, to 5 a.m. Friday, Sept. 4. I-5 will have nightly single-lane reductions from 8 p.m. to 5 a.m. near exit 240 from Aug. 31 through Sept. 4 for fish passage construction. SR 99 will close the right lane from Russell Way to Gibson Road from 8 p.m. Monday, Aug. 31, to 5 a.m. Tuesday, Sept. 1.

WSDOT advises drivers to allow extra time for commutes, watch for flaggers, and follow detour signs. The fish passage project on I-5 includes additional information on WSDOT's website. Work on SR 4 for a gas main extension will continue weekdays until Sept. 11, with lane closures from 7:30 a.m. to 5 p.m.

📄 Source: WSDOT — Highway Construction & Closures — https://wsdot.wa.gov/travel/road-construction

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I-405, I-5, and SR 99 will have multiple lane closures starting this week for construction and utility projects“405: Up to two lanes of southbound I-405 from milepost 12 to Coal Creek Parkway Southeast (milepost 10) will be closed overnight, 9 p.m. Thursday, Sept. 3 – 5 a.m. Friday, Sept. 4. 005: The northbound and southbound I-5 will be reduced to a single lane from 8 p.m. to 5 a.m. nightly Monday, Aug. 31, through Friday morning, Sept. 4, near Alger/Lake Samish Road (exit 240) for fish passage construction. 099: From 8 p.m. Monday, Aug. 31 to Tuesday, Sept. 1, the right lane of State Route 99 from Russell Way/North Manor Way to Gibson Road (milepost 51) will close for utilities work.”
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Northbound I-405 will close all lanes from Northeast 70th Place to Northeast 85th Street“405: All lanes of northbound I-405 will close from Northeast 70th Place to Northeast 85th Street from 11 p.m. Friday Aug. 28 to 5 a.m. Monday, Aug. 31. A signed detour will be in place. Effective: Aug 21, 2026, 12:00 AM Expected end: Aug 31, 2026, 5:00 AM”
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The closure of Northbound I-405 will be from 11 p.m. Friday, Aug. 28“405: Up to three lanes of northbound I-405 will close from the Northeast 85th Street on-ramp to Northeast 100th Street from 11 p.m. Friday Aug. 28 to 5 a.m. Monday, Aug. 31. A signed detour will be in place.”
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The closure of Northbound I-405 will end at 5 a.m. Monday, Aug. 31No usable supporting receipt — unverified.
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Southbound I-405 will lose up to two lanes from milepost 12 to Coal Creek Parkway Southeast“405: Up to two lanes of southbound I-405 from milepost 12 to Coal Creek Parkway Southeast (milepost 10) will be closed overnight, 9 p.m. Thursday, Sept. 3 – 5 a.m. Friday, Sept. 4.”
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The closure of Southbound I-405 will be from 9 p.m. Thursday, Sept. 3No usable supporting receipt — unverified.
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The closure of Southbound I-405 will end at 5 a.m. Friday, Sept. 4No usable supporting receipt — unverified.
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I-5 will have nightly single-lane reductions from 8 p.m. to 5 a.m.“005: The northbound and southbound I-5 will be reduced to a single lane from 8 p.m. to 5 a.m. nightly Monday, Aug. 31, through Friday morning, Sept. 4, near Alger/Lake Samish Road (exit 240) for fish passage construction.”
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The single-lane reductions on I-5 will be near exit 240“005: The northbound and southbound I-5 will be reduced to a single lane from 8 p.m. to 5 a.m. nightly Monday, Aug. 31, through Friday morning, Sept. 4, near Alger/Lake Samish Road (exit 240) for fish passage construction.”
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The single-lane reductions on I-5 will be from Aug. 31 through Sept. 4“005: The northbound and southbound I-5 will be reduced to a single lane from 8 p.m. to 5 a.m. nightly Monday, Aug. 31, through Friday morning, Sept. 4, near Alger/Lake Samish Road (exit 240) for fish passage construction.”
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The fish passage construction on I-5 includes additional information on WSDOT's website“More information on the <a href="https://wsdot.wa.gov/construction-planning/search-projects/i-5-tributaries-friday-lake-chuckanut-creeks-fish-passage">project webpage</a>.”
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SR 99 will close the right lane from Russell Way to Gibson Road“099: From 8 p.m. Monday, Aug. 31 to Tuesday, Sept. 1, the right lane of State Route 99 from Russell Way/North Manor Way to Gibson Road (milepost 51) will close for utilities work.”
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The closure of SR 99 will be from 8 p.m. Monday, Aug. 31“099: From 8 p.m. Monday, Aug. 31 to Tuesday, Sept. 1, the right lane of State Route 99 from Russell Way/North Manor Way to Gibson Road (milepost 51) will close for utilities work.”
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The closure of SR 99 will end at 5 a.m. Tuesday, Sept. 1“099: From 8 p.m. Monday, Aug. 31 to Tuesday, Sept. 1, the right lane of State Route 99 from Russell Way/North Manor Way to Gibson Road (milepost 51) will close for utilities work. Effective: Aug 28, 2026, 10:57 AM Expected end: Sep 1, 2026, 5:00 AM”
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Work on SR 4 for a gas main extension will continue weekdays until Sept. 11“004: Monday, Aug. 17 through Friday, Sept. 11: A single lane in both directions of SR 4 between 50th Avenue (milepost 56.4) and 42nd Avenue (milepost 57.2) will be closed weekdays from 7:30 a.m. to 5 p.m., for buried gas main line extension work.”
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Lane closures on SR 4 will be from 7:30 a.m. to 5 p.m.“004: Monday, Aug. 17 through Friday, Sept. 11: A single lane in both directions of SR 4 between 50th Avenue (milepost 56.4) and 42nd Avenue (milepost 57.2) will be closed weekdays from 7:30 a.m. to 5 p.m., for buried gas main line extension work.”