Public Safety

I-405, I-90, SR 20 closures for construction

Thursday, September 3, 2026

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I-405, I-90, and SR 20 will face lane closures and detours through September 4 for construction projects. The most significant changes include overnight closures on I-405 southbound from milepost 12 to Coal Creek Parkway Southeast and northbound from milepost 7 to 8.5. I-90 eastbound off-ramp to Factoria Boulevard will close nightly until September 4.

Construction on SR 20 from Swin Slough Bridge to Laconner Whitney Road will continue daily with flaggers until further notice, while SR 9 near Kalloch Road will operate with single-lane traffic through September 24. I-5 near Alger/Lake Samish Road will have reduced lanes nightly until September 10 for fish passage construction.

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

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I-405, I-90, and SR 20 will face lane closures and detours through September 4 for construction 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. 405: Up to two lanes of northbound I-405 from milepost 7 to milepost 8.5 will be closed nightly, 9 p.m. Monday, Aug. 31 – 4:30 a.m. Friday, Sept. 4. 090: The eastbound I-90 off-ramp to Factoria Boulevard will be closed nightly, 9 p.m. Monday, Aug. 31 – 5 a.m. Friday, Sept. 4. A signed detour will be in place. 020: Daily (except Saturday, Sunday) beginning Aug. 21 until further notice: State Route 20 traffic will alternate with flaggers from the Swin Slough Bridge (milepost 50) to Laconner Whitney Road/Bay View Road (milepost 53) for city Anacortes utilities work.”
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The most significant changes include overnight closures on I-405 southbound from milepost 12 to Coal Creek Parkway SoutheastNo usable supporting receipt — unverified.
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The most significant changes include overnight closures on I-405 northbound from milepost 7 to 8.5No usable supporting receipt — unverified.
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I-90 eastbound off-ramp to Factoria Boulevard will close nightly until September 4“090: The eastbound I-90 off-ramp to Factoria Boulevard will be closed nightly, 9 p.m. Monday, Aug. 31 – 5 a.m. Friday, Sept. 4. A signed detour will be in place.”
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Construction on SR 20 from Swin Slough Bridge to Laconner Whitney Road will continue daily with flaggers until further notice“020: Daily (except Saturday, Sunday) beginning Aug. 21 until further notice: State Route 20 traffic will alternate with flaggers from the Swin Slough Bridge (milepost 50) to Laconner Whitney Road/Bay View Road (milepost 53) for city Anacortes utilities work.”
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SR 9 near Kalloch Road will operate with single-lane traffic through September 24“009: SR 9 is reduced to a single lane near Kalloch Road (MP 59) with a signal alternating northbound and southbound traffic through a bypass road for 52 days, until Sept. 24 for fish passage construction.”
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I-5 near Alger/Lake Samish Road will have reduced lanes nightly until September 10 for fish passage construction“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.”