WSDOT Closure of I-90 Eastbound On-Ramp at East Mercer Way

Heads up Mercer Island commuters!  

The Washington State Department of Transportation (WSDOT) will close the I-90 Eastbound on-ramp at East Mercer Way and the HOV on-ramp at 80th Ave. SE beginning Thursday, Sept. 18, to complete essential roadway repairs and replace failing expansion joints on the East Channel Bridge.  

• The closure of the East Mercer Way on-ramp to I-90 Eastbound is expected to last 6 to 8 days. 
• The closure of the HOV on-ramp at 80th Ave SE to I-90 Eastbound is expected last 16 days. 

Additionally, one lane of traffic on I-90 Eastbound leading to the East Channel Bridge will be closed, likely causing substantial back-ups. 

The full project is anticipated to last 16 days, with access to all on-ramps slated to open on October 5. 

IMPORTANT: Expect major delays, as this closure by WSDOT is expected to be highly disruptive!   

Drivers will find it much more difficult and time-consuming to move around the Island, as well as access I-90 to leave the Island, during the closure. Detour routes will carry higher-than-normal traffic volumes and are likely to experience significant backups as drivers move through the area. 

Project Information 

WSDOT needs to close the I-90 Eastbound on-ramp at East Mercer Way (and the HOV on-ramp at 80th Ave SE) to facilitate the replacement of failed expansion joints and related work on the I-90 Eastbound East Channel Bridge.  

Between mileposts 8.24 and 8.82 (approximately), WSDOT crews will: 

• remove and replace modular expansion joints 
• apply pavement markings 
• perform temporary erosion, water pollution, and traffic control 
• other necessary work 

WSDOT requires a 6- to 8-day continuous closure of the East Mercer Way on-ramp because of the extensive nature of the repairs. Successful completion of this project depends on having relatively clear weather, which prevents WSDOT from scheduling this any later in the year.  

For questions/concerns, contact WSDOT’s Northwest Office: nwpublicaffairs@wsdot.wa.gov  

Frequently Asked Questions (Information provided by WSDOT) 

Why can’t this work be completed at night? 

The work requires more time than is available during limited nighttime hours. In addition, the large gap created when removing and replacing the modular expansion joints cannot be safely or effectively covered for temporary use, so the work must be completed during a continuous closure. 

Why can’t the work be completed solely with weekend closures? 

The work requires more time than is available during the weekend days, and the large gap cannot be temporarily covered to accommodate vehicle traffic. 

Why an extended continuous closure? 

The joints will be replaced in two halves. At the splice location, the joint is cantilevered and cannot support live traffic until the two halves are spliced and welded together. The joint replacement work is anticipated to take approximately 16 days. 

Will crews be working 24 hours per day, seven days per week? 

Yes. Crews will work around the clock to complete the project as quickly and safely as possible. 

Why can’t the 80th Ave. SE and E Mercer Way to I-90 Eastbound on-ramps remain open? 

Both on-ramps will need to remain closed because there is not enough space for traffic to safely merge due to the closure and channelization that will be in place. Additionally, the East Mercer Way on-ramp leads directly into the active work zone and must remain closed. 

Visit the WSDOT project page for more information and its Flickr project page for photos of expansion joints and the type of work that will be done throughout the closure. 

Information about the emergency I-90 lane closure in early 2024 can be found here. 

Timeline 

WSDOT will continuously close the I-90 Eastbound on-ramp at East Mercer Way and the HOV on-ramp at 80th Ave. SE during the following period: 

ALL CLOSURES BEGIN: THURSDAY, SEPT. 18, 2025 

EAST MERCER WAY ON-RAMP REOPENS: WSDOT IS TARGETING BETWEEN SEPT. 23-25, 2025 

HOV ON-RAMP AT 80TH REOPENS: SUNDAY, OCT. 5, 2025 

PROJECT ENDS: SUNDAY, OCT. 5, 2025 

During this time, no vehicles will be able to access these on-ramps at any time.  

Additionally, WSDOT will close one lane of I-90 Eastbound before the East Channel Bridge during this period, likely creating traffic backups.   

Prepare for increased traffic 

• Consider minimizing trips by rescheduling appointments to before or after the closure, postponing activities, and working remotely. 
• Know before you go if you must travel. Sign up for WSDOT travel alerts to stay informed of travel delays: download the WSDOT app or receive email alerts.  
• Review recommended detour routes (see map) and check the WSDOT Real-Time Travel Map before you leave. 
• Carpool or use public transit to help minimize the number of vehicles on roads. 
• Allow extra time to reach your destination by leaving earlier. If possible, avoid peak commute times during weekday mornings (7:00 – 9:00 AM) and afternoons (4:00 – 6:00 PM). 
• Prepare an emergency kit to keep in your car in the event of extended traffic backups. The kit should include food, water, and essential medication.  
• Parents should have back-up options if they are late to pick up children from school, daycare, or activities. Likewise, schools, daycares, and after-school activity directors should plan for delayed parents. 
• Share this information with family, friends, neighbors, and employees/co-workers so they can also be as prepared as possible. 

Detour Routes 

Signs will be placed around the Island to direct drivers to designated detour routes.  

Drivers heading eastbound on I-90 (toward Bellevue/Issaquah) and coming from East Mercer Way have two options: 

1. Navigate to Island Crest Way and use the I-90 Eastbound on-ramp; or 
2. From East Mercer Way, use the I-90 Westbound on-ramp, exit at Island Crest Way, and then use the I-90 Eastbound on-ramp 

Drivers heading westbound on I-90 (toward Seattle) can use any westbound exit.