Weekend traffic: prepare for delays on I-405 near Kirkland, I-5 near Dupont

Drivers heading out this weekend should prepare for delays as construction projects affect both I-405 in Kirkland and I-5 near DuPont.

Full northbound I-405 closure planned in Kirkland

Travelers along the I-405 corridor through Kirkland are expected to see backups as crews continue work on the I-405/NE 85th Street Interchange and Inline BRT Station Project.

All lanes of northbound I-405 will close between NE 70th Place and NE 85th Street from 11 p.m. Friday, Aug. 28, until 5 a.m. Monday, Aug. 31.

In addition to the freeway closure, up to three northbound lanes will be closed from the NE 85th Street on-ramp to NE 100th Street. The NE 70th Place on-ramp to northbound I-405 and the northbound I-405 off-ramp to NE 85th Street will also be closed.

A signed detour will be in place. Drivers can exit at Northeast 70th Place, use 116th Avenue Northeast and 120th Avenue NE to reach NE 85th Street, and then rejoin I-405. Motorists should plan for delays and leave early.

According to the Washington State Department of Transportation (WSDOT), crews will dig out a section of the freeway to install a concrete culvert that will reconnect fish passage beneath northbound I-405 to a section under southbound I-405 that was constructed during a full closure in July.

The NE 85th Street on-ramp to northbound I-405 will remain open.

Southbound I-5 reduced near DuPont and JBLM

Drivers traveling south on I-5 through DuPont and Joint Base Lewis-McChord (JBLM) should also expect delays this weekend.

Beginning at 9 p.m. Friday, Aug. 28, and continuing through 4:30 a.m. Monday, Aug. 31, southbound I-5 will be reduced to three lanes approaching DuPont.

WSDOT advises travelers to add at least 20 minutes of extra travel time.

The lane reduction will allow crews to reroute drainage beneath I-5. The work includes asphalt grinding, paving, and installation of temporary lane markings.

Drivers are encouraged to plan ahead and expect slower travel through the work zone.

WSDOT said the work could be rescheduled if rain is forecasted.

Additional Seattle-area I-5 restrictions

Drivers traveling through Seattle should also be aware that northbound I-5 remains reduced to two lanes across the Ship Canal Bridge through the end of 2026. The express lanes remain open northbound only 24 hours a day, and the Harvard Avenue on-ramp to northbound I-5 is closed until mid-October.

With construction projects and weekend events expected to increase traffic volumes across the region, drivers should allow extra travel time and be prepared for delays.