UPDATED | AUGUST 14, 2024
WSDOT announced today that the scheduled closure of the SR 18 on-ramp to westbound I- 90 Wednesday night, Aug. 14, has been delayed. The work will be rescheduled to a later date. Once that new date is announced, another update will be posted.
ORIGINAL NEWS RELEASE | AUGUST 13, 2024
The Washington State Department of Transportation (WSDOT) announced that the I-90/SR 18 Interchange Improvements project will reach a major milestone over the next two weeks when the first ramps of the new diverging diamond interchange open to traffic near Snoqualmie. The first ramp switch will occur overnight on Wednesday, Aug. 14, along the SR 18/Snoqualmie Parkway on-ramp to westbound I-90.
During the switch, the existing SR 18 on-ramp to westbound I-90 will close at 9 p.m. Wednesday, Aug. 14. The new ramps will open by 5 a.m. Thursday, Aug. 15. A signed detour during the closure will use eastbound I-90 and loop around at Winery Road/Southeast North Bend Way (exit 27).
Once the new westbound I-90 on-ramps open on Thursday morning, people should pay attention to the new striping and signs.
Second ramp switch
The eastbound I-90 off-ramp to SR 18 will close at 9 p.m. Thursday, Aug. 22, and traffic will move to that new ramp beginning at 5 a.m. Friday, Aug. 23. People can follow a detour during the closure, continuing eastbound on I-90, looping around to westbound I-90 at Winery Road/Southeast North Bend Way (exit 27) and using the off-ramp to SR 18/Snoqualmie Parkway.
The new on and off-ramps will be the first portion of a new diverging diamond interchange to open to traffic. The full interchange is on schedule to open in late 2024.
Diverging diamond interchange
The diverging diamond interchange was identified by WSDOT in 2016 as the preferred way to improve efficiency and safety at the busy interchange. Once completed, it will be the second diverging diamond interchange in the state and will allow through traffic and left turns at the same time to improve traffic flow and reduce collisions.
Along with building the new interchange, the full project, which will finish in late 2025, will:
- Widen two miles of SR 18, providing two lanes in each direction between I-90 and Deep Creek.
- Build a new two-lane bridge over the Raging River next to the existing bridge.
- Construct two new four-lane bridges over Deep Creek and Lake Creek.
- Replace six fish passage barriers with relocated open channel streams.
- Improve habitat connectivity for wildlife, including deer and elk.