Just about every weekday morning, traffic on Snoqualmie Parkway backs up to about Jacobia Street in Snoqualmie, WA. As you can see, all those drivers are trying to make a right hand turn onto westbound I-90. The current interchange is set up so those Snoqualmie Parkway drivers must wait their turn after oncoming traffic like that dump truck takes its turn. Waiting for each light to run through the full cycle takes time. As part of the I-90/SR 18 interchange improvement project, we will build a diverging diamond interchange at this intersection. Diverging diamonds have fewer traffic lights and allow more free right and left turns. In interim, we will rebuild the ramp onto westbound I-90 to allow Snoqualmie Parkway drivers to make a free right turn into a dedicated on-ramp lane. That means those drivers won't have to wait for other traffic, reducing congestion. The modified on ramp is scheduled to open by the end of 2019. Construction on the new interchange is scheduled to begin in 2021 with completion in 2023.
www.wsdot.wa.gov/Projects/I90/SR18ICImprove/default.htm 