State Route 18 will close overnight under the Interstate 90 bridges near Snoqualmie Friday, July 31, and Saturday, Aug. 1, to install permanent striping throughout the diverging diamond interchange. All right-turning ramps will remain open at the SR 18/I-90 Interchange during this full closure. These will be the final planned full closures for the I-90/SR 18 Interchange Improvements and Widening project, according to WSDOT.
Crews will also close the westbound Interstate 90 off-ramp to westbound SR 18 and Snoqualmie Parkway from 9 p.m. Thursday, July 30, to 5 a.m. July 31 to complete striping work on the ramp.
What to expect July 31-Aug. 2
Closures will take place from 8 p.m. to 6 a.m. nightly beginning Friday night, July 31, and finishing Sunday morning, Aug. 2. All right-turning on- and off-ramps at the interchange will remain open during this full closure.
Both directions of traffic using I-90 will not be affected during these closures, but people traveling through the area should be aware that:
- Vehicles will not be permitted on either direction of SR 18 beneath the I-90 bridges.
- Traffic on the eastbound and westbound I-90 off-ramps will only be able to turn right.
- Eastbound SR 18 traffic must follow a detour using the eastbound I-90 on-ramp.
- Southbound traffic on Snoqualmie Parkway must follow a detour using the westbound I-90 on-ramp.
These closures depend on dry weather and may be rescheduled on short notice if rain is in the forecast. People traveling through the I-90/SR 18 interchange should plan ahead, add extra time for travel, and follow signed detours as necessary.
Detour routes
People can detour around these closures using eastbound and westbound I-90 and loop around at nearby interchanges – Highpoint Way (exit 20) to the west and Southeast North Bend Way/Winery Road (exit 27) to the east.
- Westbound I-90 to westbound SR 18: Continue westbound on I-90 to exit 20, High Point Way, loop back to eastbound I-90 and exit at SR 18/Snoqualmie Parkway.
- Westbound SR 18/Snoqualmie Parkway to eastbound I-90: Use the westbound I-90 on-ramp to exit 20, High Point Way, and loop back to eastbound I-90.
- Eastbound SR 18 to westbound I-90: Use the eastbound I-90 on-ramp to exit 27, North Bend/Snoqualmie (Winery Road), and loop back to westbound I-90.
- Eastbound I-90 to Snoqualmie Parkway: Continue eastbound on I-90 to exit 27, North Bend/Snoqualmie (Winery Road), loop back to westbound I-90 and exit at SR 18/Snoqualmie Parkway.
- Eastbound SR 18 to northbound Snoqualmie Parkway: Use the eastbound I-90 on-ramp to exit 27, North Bend/Snoqualmie (Winery Road) loop back to westbound I-90, then exit at SR 18/Snoqualmie Parkway.
- Southbound Snoqualmie Parkway to westbound SR 18: Use the westbound I-90 on-ramp to exit 20, High Point Way, loop back to eastbound I-90, then exit at SR 18/Snoqualmie Parkway
To help keep traffic moving smoothly, the Preston/Fall City exit on westbound I-90 should be used primarily by local traffic. Travelers can potentially save time by using the signed detour at Southeast High Point Way or by using alternate routes.
Freight traffic should not use Issaquah city streets or Issaquah-Hobart Road, which are not suitable for semi-trucks. Similarly, eastbound SR 18 freight traffic cannot use Issaquah city streets to access I-90.
[Information provided by the Washington State Department of Transportation (WSDOT)]
