WSDOT tests new signal timing at SR 18/ I-90 interchange, proves unsuccessful

Did the commute home seem longer recently? Some Snoqualmie Ridge residents may have noticed longer backups at the SR-18/I-90 over the past week. If you thought you were waiting longer than usual – and sitting on I-90 when you usually didn’t – you weren’t imagining it.

According to the Washington State Department of Transportation, on Wednesday, June 7, engineers altered the signal timing at the SR 18/Eastbound I-90 interchange. This was done in coordination with the Washington State Patrol (WSP) in hopes of reducing the number of vehicles that block the intersection.

Some Snoqualmie residents did notice the dramatic change, saying early this week the left-turn exit only lane from EB I-90 at exit 25 was backed up onto the freeway even after the usually backed up right-turn exit only lane had cleared toward the end of the evening commute.

WSDOT said the new signal timing did not prove successful and so it was changed back to the previous timing sequence. WSDOT added that signal engineers will continue to work with WSP to monitor the busy intersection in order to improve traffic flow for all commuters.

The $150 million, multi-year project to improve the congested and signal-controlled interchange will begin this summer, when design commences on a plan to reconfigure busy, choke-point area into to a Diverging Diamond Interchange and widen SR 18 from I-90 to the Raging River.  The project is estimated to be finished around 2022-2023.

You can read more about the I-90/SR 18 interchange improvement plan HERE.

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  • I was headed West on I-90 wanting to go on to SR 18 on Sunday PM. The long line of vehicles on I-90 moved to the stop light more quickly than I have ever experienced. I would say that for that route the altered timing was a great success…….I would hope they would put some more thought into the signal timing instead of giving up.

  • I was heading East on I-90 (home) last week and noticed that both lanes for Hwy 18 and Snoqualmie were both backed up instead of just the Hwy 18 lane most days. To me that is just to dangerous having both lanes backed up for a couple miles.

  • In fact, I-90 eastbound was gridlock in all four lanes (halfway up the hill from the Preston soccer fields) to Hwy 18 on two consecutive weekdays during the late afternoon commute. There’s got to be a better way to study the patterns, please.

  • Living Snoqualmie