I-90 - Snoqualmie Pass East - Hyak to Keechelus Dam (Phase 1) - Complete October 2019

Why did WSDOT  improve safety and reliability on I-90?

Phase 1 was part of a 15-mile corridor improvement project to improve safety and reliability and reduce congestion along I-90 from Hyak to the Easton vicinity. On average, 31,000 vehicles travel over Snoqualmie Pass every day and this number doubles on weekends and holidays. Traffic volumes are expected to increase 1 percent every year, reaching an average of over 39,000 vehicles per day by 2040. 

The End Result

WSDOT increased capacity and improved safety by:

  • Adding a new lane in each direction
  • Replacing deteriorating concrete pavement
  • Reducing road closures due to avalanches
  • Adding and replacing bridges and culverts
  • Straightening sharp curves
  • Stabilizing rock slopes

Needs & Benefits

  • Safety. Corrective measures reduced the risk of avalanche and associated road closures within the project area as well as reduced the risk of rock and debris slides from unstable slopes onto the roadway.
  • Congestion Relief. WSDOT increased capacity by 50 percent in each direction to accommodate projected traffic volumes for the next 20 years. Crews extended chain-up-and-off areas assisting freight vehicles.
  • Environment. WSDOT reduced the risk of collisions between wildlife and vehicles by building wildlife crossings.


  • Spring 2009 - construction began
  • Fall 2019 - construction completed


Funding Source ($ in Thousands)
$453,702 from 2005 gas tax (TPA)

This project recently had construction change orders of more than $500,000.  View all change orders.


Jerry Wood
Project Engineer
Phone: 509-577-1859

Summer Derrey
Phone: 509-577-1943

Thumbnail - I-90 - Phase 1 and 2 map

I-90 des vis thumb nail

Design Visualization of the I-90 Snoqualmie Pass East project.

Screenshot from Lifeline video

I-90 is a major transportation corridor in Washington state, find out why.