If you regularly travel on eastbound Interstate 90 between Preston and Snoqualmie, you are probably aware of the frequent backups near the State Route 18 off-ramp during peak commute periods. Although construction to improve the I-90/SR 18 interchange is scheduled to start in 2021, we're continuing to implement low-cost improvements to manage congestion and improve safety in the interim.
Recently, contractor crews from Northeast Electric, LLC installed two new active warning signs on eastbound I-90 just west of the SR 18 off-ramp. The first sign is approximately two miles before the I-90/SR 18 interchange, and the second sign is about a mile before the interchange. These signs will be activated in summer 2019.
|Location of the two new active warning signs on eastbound I-90.|
The signs are wired to automatically turn on when traffic ahead is slowed or stopped, giving drivers more time to slow down in order to prevent rear-end collisions.
|When activated, the signs will read "stopped traffic ahead," and will have two flashing beacons at the top.|
Like this sign, we've also implemented many other low-cost improvements to help keep travelers moving safely until an improved interchange is built. Here's what we've done so far:
- Widened the eastbound I-90 off-ramp to SR 18
- Changed the right lanes of eastbound and westbound I-90 to exit-only lanes
- Partnered with the City of Snoqualmie to change the lane configuration on southbound Snoqualmie Parkway - making the right lane a right-turn-only lane to the westbound I-90 on-ramp
- Adjusted the signal timing at the two intersections to operate the interchange as efficiently as possible
- Installed "Thru traffic keep left" signs on both directions of I-90 prior to the SR 18 interchange to guide through-traffic to stay in the left two lanes and keep the right lanes clear for drivers exiting to SR 18 or Snoqualmie Parkway
- Installed "No U-turn" signs on SR 18 at the interchange to prohibit U-turns that have caused congestion for the off-ramp traffic
Upcoming I-90/SR 18 interchange improvements
The I-90/SR 18 interchange improvement project is one of the bigger projects in the 2015 Connecting Washington transportation package. The Legislature designated $150 million to implement improvements. At this time, a Diverging Diamond Interchange (DDI) is the leading concept, as we believe this can provide improved traffic flow and congestion relief for all of the movements at the I-90/SR 18 interchange. However, we plan to conduct extensive community engagement, traffic and environmental analysis as an interchange design is developed and refined.
Until the improved interchange is complete in 2023, we will continue to monitor traffic in the area and make low-cost improvements when feasible.