Local Information

Project to improve northbound I-5 through downtown Seattle starts May 17

Monday, May 10, 2021 - 10:25

Tom Pearce, communications, 206-440-4696

Work will eliminate bottleneck near Seneca Street, add ramp meters and traffic flow signs

SEATTLE – Much has changed with Interstate 5 through Seattle since it was built in the 1960s. But one original feature remains – an exit-only ramp to Seneca Street and two through lanes just north of that.

Starting Monday, May 17, a project kicks off to expand that 1,500-foot section to three through lanes between Seneca Street and the Washington State Convention Center.

In addition to creating a third lane, contractor crews working for the Washington State Department of Transportation will add ramp meters and an advance signing system to warn drivers of incidents that block lanes.

This project will take about a year and a half to complete. When finished, it will help reduce congestion as traffic reaches downtown Seattle.

What travelers can expect
Work will take place at night to limit the effects on people who travel through this area. Northbound I-5 between I-90 and downtown Seattle will close from midnight to 4:30 a.m. on 10 to 12 nights to accomplish the work. When possible, the express lanes will open northbound as an alternative. Otherwise, drivers will need to seek alternate routes like State Route 99, Interstate 405 or city streets. The dates for the closures have not yet been set.

Some nights all northbound I-5 traffic will detour through the collector-distributor lanes to provide a safe work zone for the crews. Cherry and James streets under northbound I-5 also will be closed for four to five nights, along with several on- and off-ramps in the collector-distributor lanes.

Three-part project will help traffic
This project will make improvements in three areas by:

  • Changing the exit-only lane to Seneca Street into a through lane. Currently at Seneca, northbound I-5 reduces to two lanes for about 1,500 feet. This project will slightly widen I-5 in that area, changing the exit-only lane to a through lane so the freeway has three lanes all the way through that area.
  • Adding a second lane to the on-ramp for I-90/Dearborn Street to northbound I-5. Both of these lanes with have ramp meter signals, as will the Cherry Street on-ramp, to create gaps between cars entering the freeway that make it safer to merge.
  • Adding an advance signing system to provide drivers with information about incidents and lane closures, improving traffic flow and safety for drivers, first responders and road crews.

People traveling can find updated traffic information on the Seattle area construction webpage and the @WSDOT_traffic Twitter feed.


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