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I-90 Snoqualmie Pass East (SPE) Project – What’s Phase 3?

The third phase of the I-90 Snoqualmie Pass East project improves six miles between the Cabin Creek Interchange to the West Easton Interchange. Starting in 2021, drivers will use the detour route (orange on map) so crews can add lanes.

Phase 3 is 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. 

This phase includes approximately six miles of improvements between the Cabin Creek Interchange to the West Easton Interchange.  

Design visualization of the Hudson Creek crossing and the wildlife undercrossing on Amabilis Grade.

The end result

WSDOT will increase traffic capacity and improve safety by:

  • Adding a new lane in each direction
  • Replacing concrete pavement
  • Stabilizing rock slopes
  • Building wildlife crossings
  • Improving sight distance and traffic safety
  • Replacing truck climbing lanes
  • Improving Traffic Management Technology Systems

Needs and benefits

Safety. WSDOT will increase traffic safety by replacing existing concrete pavement, improving driver sight distance, improve shoulders and investing in new Traffic Management Technology.

Congestion Relief. WSDOT will increase freight and mobility reliability of this increasingly important transportation corridor by adding an additional lane in both directions.

Environmental. WSDOT partnered with state, federal and private groups to deliver a streamlined mitigation strategy to address water quality, aquatic life and wildlife goals in this unique Cascade Mountain area.


Summer 2021 – construction begins
Fall 2025 – scheduled completion

Design visualization of the wildlife overcrossing located near Easton Hill.