A planned five-day closure of State Route 18 at Interstate 90 has been canceled due to expected rain, the Washington State Department of Transportation announced Thursday.
The closure was originally scheduled to begin at 9 p.m. Thursday, May 15, and continue through 5 a.m. Wednesday, May 21. It would have closed SR 18 in both directions under I-90—one of the most heavily traveled and congested interchanges in Washington state.
WSDOT now says the closure will be rescheduled for a date after Memorial Day.
New dates have not yet been set, but the department said it would provide an update once a new schedule is confirmed.
The closure was part of ongoing construction to build a new diverging diamond interchange at I-90 and SR 18, a design aimed at improving traffic flow and safety in the area. Once completed, this will be only the second diverging diamond interchange in the region.
While the canceled closure delays a major milestone, WSDOT says the overall project remains on track.
According to spokesperson David Rasbach, traffic could shift onto the new Deep Creek and Raging River bridges in early June.
“Definitely expect extra time, plus you’ve got to factor in the little extra distance you have to travel for the detours looping out to the next interchanges,” Rasbach said in an earlier briefing on the closure plans.
Although this closure is postponed, Rasbach said drivers should expect additional impacts later this year. Crews still need extended time to complete the north end of the interchange, which could result in another long-term closure or a series of shorter ones. “That is still to be determined,” he said.
Construction on the full interchange is expected to finish this summer, with the widening of SR 18 just south of I-90 wrapping up in the fall.
Once complete, WSDOT will begin widening and paving SR 18 down the west slope of Tiger Mountain toward Issaquah-Hobart Road.
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