Infrastructure

I-405, SR 20 closures for construction

Sunday, August 30, 2026

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Starting Thursday, Sept. 3, up to two lanes of southbound I-405 will close from milepost 12 to Coal Creek Parkway Southeast until 5 a.m. Friday, Sept. 4.

State Route 20 will alternate traffic with flaggers daily (except weekends) from Swin Slough Bridge to Laconner Whitney Road/Bay View Road for Anacortes utilities work beginning Aug. 21.

WSDOT projects include fish passage construction near I-5 exits 240 and 246, with single-lane reductions nightly until Sept. 10. SR 4 work between 50th and 42nd Avenues will close one lane weekdays until Sept. 11.

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

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Starting Thursday, Sept. 3, up to two lanes of southbound I-405 will close“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 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 last until 5 a.m. Friday, Sept. 4No usable supporting receipt — unverified.
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State Route 20 will alternate traffic with flaggers daily“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 traffic alternation on State Route 20 will exclude weekendsNo usable supporting receipt — unverified.
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The traffic alternation on State Route 20 will be from Swin Slough Bridge to Laconner Whitney Road/Bay View Road“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 traffic alternation on State Route 20 will start on Aug. 21“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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WSDOT projects include fish passage construction near I-5 exits 240 and 246No usable supporting receipt — unverified.
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Single-lane reductions for fish passage construction near I-5 exits 240 and 246 will occur nightlyNo usable supporting receipt — unverified.
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The single-lane reductions for fish passage construction near I-5 exits 240 and 246 will last until Sept. 10No usable supporting receipt — unverified.
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SR 4 work between 50th and 42nd Avenues will close one lane“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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The one-lane closure on SR 4 between 50th and 42nd Avenues will occur weekdays“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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The one-lane closure on SR 4 between 50th and 42nd Avenues will last 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.”