project:

I-90 Two Way Transit and HOV Operations Stage 3

Sound Transit

Location:

Seattle, Washington

Estimated Cost:

$185 million

Service:

Constructability Review

Market Sector:

Transportation

Facility Specialty:

Highways, streets, parking lots

Designer:

WSDOT/Jacobs

PROJECT DESCRIPTION

The I-90 Two Way Transit and HOV Operations Stage 3 began construction after the completion of the first two phases that worked on the Eastbound and Westbound HOV lanes from Bellevue Way to 80th Ave SE. Phase 3 focused on the rest of the HOV lanes from 80th Ave SE to Ranier Ave.

Phase 3 required:

• Structural interdisciplinary coordination between teams

• Balancing

• Testing

• Risk assessments

• Commissioning of ventilation

• Fire suppression

• SCADA

• ITS systems - in order to maintain properly balanced existing systems until the transitional and new systems are phased in. 

​

The focus of the constructability review was on the HOV lane to and from Seattle to improve the tunnel fire/life safety systems, improve Mount Baker Ridge and Mercer Island tunnels, bike path screening, as well as adjustments to accomidate for the East Link Light Rail project.