In Washington State, Interstate 90 is a critical link connecting Puget Sound’s large population and business centers with the farmlands, diverse industries and extensive recreational areas of eastern Washington. It is being expanded – at a cost of $525 million – to meet both the current and future needs of those who travel the pass.



In Washington State, Interstate 90 is a critical link connecting Puget Sound’s large population and business centers with the farmlands, diverse industries and extensive recreational areas of eastern Washington. The uninterrupted movement of people, freight and business over Snoqualmie Pass is essential to the quality of life and economic vitality of the region. Interstate 90 is being expanded – at a cost of $525 million – to meet both the current and future needs of those who travel the pass.

Some of the issues addressed:

Traffic congestion – Each year, 35 million tons of freight and 10 million vehicles travel over Snoqualmie Pass. Traffic volumes continue to increase, reaching 58,000 vehicles per day during peak travel periods.

Deteriorating pavement – The highway pavement on I-90 is between 30 years old and 50 years old, and has exceeded its lifespan. Extreme weather conditions and heavy usage have rapidly deteriorated the asphalt pavement.

Sharp curves – There are numerous sharp curves that limit visibility throughout the corridor, resulting in an unacceptable accident rate.

Avalanche closures – I-90 is closed an average of 80 hours per year due to avalanches, costing business and private travelers an estimated $17.5 million annually.

Unstable slopes – Falling rocks from unstable slopes ranging in size from small stones to complete slope failures have caused serious accidents and closed traffic lanes.

Habitat connectivity – The highway serves as a barrier dividing wildlife habitats.

The project, to be completed in 2015, will meet these concerns and provide additional benefits. A wider median will provide areas for snow storage and storm water treatment, and improve safety by increasing sight distances. Chain on/off areas will be extended to improve operations and safety. Truck climbing lanes will be lengthened to improve traffic flow. Interchange bridges will feature higher clearances.
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