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I-90 - Two-Way Transit and HOV Operations


February 2017


WSDOT and Sound Transit are adding high occupancy vehicle (HOV) lanes to the outer roadways (existing general purpose lanes) in both directions of I-90 between Seattle and Bellevue. This collaboration is making vital improvements for traffic flow on I-90 while preparing the center roadway for Sound Transit's East Link light rail extension from Seattle to Mercer Island, Bellevue and Redmond.

Why is WSDOT working with Sound Transit on I-90?
WSDOT is collaborating with Sound Transit to make the best use of tax-payer transportation dollars by moving more people, more efficiently through one of the state's busiest rush-hour commutes.

I-90 includes two reversible express lanes between Seattle and Bellevue for buses, carpools and vanpools. In the morning, traffic in the express lanes are westbound; in the evening they go eastbound. Buses and high-occupancy vehicles traveling opposite the express lanes must use the outer roadway. With no HOV lanes in outer roadway at the start of this project, buses and carpools experienced routine, rush-hour delays, undermining the benefits of ride sharing.

WSDOT and Sound Transit are adding an HOV lane in both directions of the outer roadway and new direct-access ramps for transit and HOVs on Mercer Island and in Bellevue.

Stage 1  completed 2008

Westbound I-90 Bellevue-Mercer Island
  • Added a westbound I-90 HOV lane to the outer roadway, Bellevue Way SE to 80th Ave. SE
  • Built westbound I-90 HOV direct access exit ramp at 80th Ave. SE on Mercer Island
  • Modified existing ramps at Bellevue Way SE for two-way HOV operation

Stage 2  completed 2012

Eastbound I-90 Mercer Island-Bellevue
  • Added HOV lane to outer roadway 80th Ave. SE to Bellevue Way
  • Modified existing reversible HOV direct access ramp at 80th Ave. SE to an HOV on-ramp to the new HOV lane in the outer roadway of eastbound I-90
  • Preserved I-90 pavement in both directions between West Mercer Way and Bellevue Way

Stage 3  in construction 

Both directions I-90 Seattle-Mercer Island
    Stage 3A:
  • Construction finished in May 2015.
  • Reconstruct and reposition the HOV ramps from eastbound I-90 to Bellevue Way and I-405. 

    Stage 3:
  • Construction began in January 2015 and is expected to be complete in mid-2017.
  • Add an HOV lane in each direction of outer roadway between Mercer Island and Seattle.
  • Preserve pavement in both directions, I-5 to Lake Washington.
  • Build eastbound HOV direct access exit ramp at Island Crest Way on Mercer Island.
  • Upgrade I-90 tunnels fire and life safety systems in Seattle and Mercer Island.

The End Result

The project will improve on-time reliability and access for transit and HOVs on I-90. With new direct-access ramps, carpools, vanpools and buses will access the freeway directly to or from HOV lanes without merging through lanes of traffic. Traffic on the outer roadway will be smoother and safer for everyone.

The project also prepares the center roadway for Sound Transit's 14-mile East Link light rail extension from Seattle to Redmond.

Project Benefits

  • Safety: Reduces weaving and merging on I-90
  • Congestion Relief: Removes buses, carpools and vanpools from general purpose lanes, resulting in improved transit schedule reliability and shorter commute times for all drivers.
  • Improved transit reliability: Provides full-time HOV lanes in both directions for transit and carpools, making commutes by bus faster and more reliable.
  • Environment: Adds to existing drainage and storm water treatment systems to clean roadway runoff

What is the project timeline?

  • March 2007-October 2008 – Stage 1 construction
  • January-May 2010 - ARRA funded pavement preservation construction
  • Spring 2010-March 2012 - Stage 2 construction
  • May 2014 to  May 2015 - Stage 3A construction
  • January 2015 to mid-2017 - Stage 3 construction

Financial Information

The following funding sources help fund the project:

How can I get more information?
Annie Johnson
WSDOT Communications

Zack Ambrose
Sound Transit Community Outreach

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