Traffic Alert - Extended Lane Closures at I-90SR 18 Interchange Start May 15 at 9 pm

The Washington State Department of Transportation (WSDOT) will close both directions of SR 18 beneath I-90 for over five days starting May 15, 2025. This closure aims to facilitate the construction of the new diverging diamond interchange, part of the I-90/SR 18 Interchange Improvements project. Residents can use alternate routes via exits 22, 27, and 31 during this period. Crews will install new drainage systems, pave the road, and construct concrete islands, improving the interchange's safety and functionality. WSDOT anticipates that this extended closure will eliminate the need for 10 consecutive nights of further ramp and intersection closures.

When SR 18 reopens on May 21, most southern interchange construction will be complete, though additional work remains under the I-90 bridges. The project also includes widening SR 18 and building new bridges to enhance wildlife passage. Completion of the SR 18 widening is expected later this year.