Making the I-90 Interchange Work Better for Rainier Avenue South

By: April Delchamps

Playing smart, not just playing hard

The Seahawks are heading to the Superbowl! Whether you're preparing for gameday or watching highlights from past games, one thing stands out: winning is not just about effort; it is about strategy and teamwork. The best teams make smart decisions. They adapt to changing conditions and use every part of the field effectively.

You do not win games by doing the same thing over and over when it is not working. You adjust. You read the situation. You make choices based on what is actually happening, not just what you wish would happen.

That is exactly the approach we are taking with Rainier Avenue South as part of the Judkins Park Station – Reconnecting Communities Study.

Map of the Judkins Park area with the I-90 ramps endpoints shown as orange dots.

What is this study about?

WSDOT is studying ways to change the Intersate-90 ramps. Our goals are:

• Improving safe travel for all, especially pedestrians and people biking at I-90 ramp termini.
• Increasing community connectivity and access to the Judkins Park Link light rail station for those who ride transit, walk, bike and roll.

To learn more, check out the webpage: I-90 Judkins Park Station – Reconnecting Communities | WSDOT

Our study follows a clear seven step process to find the best solutions for reconnecting the community. Check out our September 2025 blog post to learn more about the process.

Community input: strategy based on local knowledge

We heard you loud and clear: you want to prioritize walking, rolling and biking, while keeping vehicle access to businesses, homes and services. In response, we are modeling the total number of lanes (driving lanes and bus lanes) from six to four. Learn more about your feedback on our September blog post.

Understanding the playing field

Interstates are designed for moving vehicles efficiently and quickly. The vision for Seattle is that moving around city streets should be safe, equitable and sustainable. All people and businesses can access their daily needs and feel connected to their community.

What Rainier Avenue South looks like

Currently, there are six traffic lanes where the I-90 ramps meet Rainier Avenue South in Judkins Park, including two bus priority lanes.

Today's Rainier Avenue South under I-90 has six lanes.

We are modeling different options for the total number of lanes to include options between four and six lanes at this location.

This matters to your daily life because it affects how you get around. Whether you drive, take the bus, walk or bike, this decision shapes your experience traveling through Judkins Park.

Testing different traffic scenarios

Good coaches do not just show up on game day and hope for the best. They study films, run practice scenarios, and test different formations. Our key question: How many lanes do we need on Rainier Avenue South at the I-90 interchange?

We fully acknowledge that Seattle is growing. The population is increasing, and people will be making more trips than ever. But here is the key difference: not everyone will be driving a car to do it.

To expand travel options and continue moving people and goods throughout a growing city without the need to widen roads, our region is investing heavily in travel options: new light rail routes, RapidRide bus service and improved walking and biking routes. The logic is simple but powerful: when people have high-quality, reliable travel options, they actually use them. By diversifying our transportation network, we protect the character of our city while ensuring everyone can get where they need to go efficiently.

We tested two main scenarios for traffic between now and 2050:

• Scenario A: Flat growth of traffic - Traffic volumes stay similar to what we see today. Even if the same number of cars keep using Rainier Avenue South between the I-90 ramps, four lanes can continue to support traffic moving with congestion during the busiest times of the day.
• Scenario B: Reduced growth of traffic – Traffic volumes decrease because more people shift to transit, walking, rolling and biking. With fewer vehicles on the road, four traffic lanes with (one lane for vehicles and one lane for buses (outside lane) in each direction) can keep people and goods moving.

Both scenarios support reducing the number of lanes in three out of the four alternatives.

Why four lanes: working smarter, not bigger

We coordinated with SDOT to model scenarios that would potentially reduce Rainier Avenue South to four lanes at the I-90 interchange to improve conditions for people walking, biking and rolling. Modeling these scenarios will help us identify our preferred option for changing the I-90 ramps. Here's what we found:

Four lanes is the minimum number of lanes we need to keep traffic and freight moving and support reliable bus service. It also supports better facilities for people walking, rolling and biking. Four lanes allow buses to stop in a dedicated bus lane, rather than merging in and out of traffic, improving transit reliability.

Remember that this is just what we've studied – any actual changes to Rainier Avenue South would be determined by SDOT working closely with community and other agency partners.

Much like a football game, using available space is important when designing pedestrian and bike improvements.

Dedicated transit lanes, bike lanes and pedestrian options – the key to making this work

How we use the field matters. Bus lanes, bike lanes and pedestrian improvements are key pieces for this area. We are prioritizing the modes that move the most people most efficiently.

Why dedicated transit lanes matter:

• Transit moves more people: One bus with its own lane replaces dozens of cars.
• Reliability changes behavior: When buses arrive on schedule because they have dedicated lanes, more people choose transit. SDOT recently completed extension of the northbound bus lane on Rainier Avenue South from South Walden Street to South State Street in summer 2025 and Route 7 riders have already seen an average saving of up to 5 minutes per trip during the busiest morning hours.
• Access for everyone: Reliable transit serves the communities that depend on it most. For people who cannot drive, cannot afford a car or choose not to drive, it is how they get to work, school, medical appointments and everywhere else.
• Increased ridership and connections: Rainier Ave South is an important transit corridor, serving tens of thousands of daily riders on King County Metro bus routes 4, 7, 9, 48, 50 and 106. Route 7 alone serves an average of 12,000 daily weekday riders (as of September 2025). Bus lanes facilitate better connections with other transit options in the Rainier Valley, such as Mount Baker Transit Center, Mount Baker Light Rail Station, and the soon-to-open Judkins Park Light Rail Station.

Why bike lanes and pedestrian improvements matter:

When walking, rolling and biking are comfortable, more people can use them for everyday trips. Features like protected bike lanes and protected crossings make these options work for people of different ages and abilities. This is especially important near the new light rail station, where many people will arrive this way, including families, students, and seniors.

The Study's recommended configuration: One bus lane and one vehicle lane in each direction, plus dedicated space for people walking, rolling and biking. This balances multiple needs while prioritizing what works best for the most people.

What does this alternative mean for you?

If you drive

• Two lanes will remain for cars (one lane in each direction).
• Expect some congestion during rush hour.
• You will still be able to access local businesses and services.

If you take the bus

• Your bus will have its own dedicated lane.
• Buses will not get stuck in traffic.
• More reliable arrival times: you can plan your schedule with more confidence.
• Frequent buses, especially during rush hour.
• Better connections to the new light rail station.

If you walk, roll or bike

• More crossings with fewer lanes of traffic to navigate.
• More space dedicated to walking, rolling and biking.
• Better connections to the light rail station.
• Separated (protected) bike lanes where possible.
• Improved sidewalks and crosswalks.

If you own or work at a local business

• Customers can still drive to your business.
• Better transit access brings more potential customers.
• People walking, rolling, and biking are more likely to stop at local shops.
• Deliveries and loading zones will still be accessible.

Team coordination: WSDOT and SDOT working together

The best teams in football are not just talented, they work together.

Many agency partners are working together in this area: Seattle Department of Transportation (SDOT), Seattle Office of Planning and Community Development, Seattle Parks and Recreation, King County Metro Transit, Sound Transit and more. We work together, with approaches that support each other.

Rethinking the I-90 ramps will impact Rainier Avenue South. Because of this, we are working with SDOT on details for Rainier Avenue South:

• SDOT and WSDOT have already made near-term improvements in the area. These are quick changes that address some current conditions. Learn more at their I-90/Judkins Park Station Near-Term Crossing Improvements webpage.
• WSDOT is working on long-term solutions to rethink the I-90 ramps with this study.
• SDOT has a paving project on Rainier Avenue South between South Jackson Streets and South Walden Street funded by the 2024 Seattle Transportation Levy. SDOT will engage with the public agency partners on how to modernize this segment of Rainier Avenue South to improve safety, equity, and sustainability.
• WSDOT and SDOT meet regularly, share data and align our approaches. When one of us does something, the other is participating and ready to support, as much as possible.

What is happening now

The engineers are evaluating the four alternatives. Learn more about all four alternatives in our December blog post.

In the coming months, we will share draft results from our alternatives analysis and select the preferred alternative and move forward with detailed design work. The specific design details will depend on which alternative we select. Each alternative has different implications for how the street will function.

Working in partnership with other agencies and by continuing to collect input from the public, we will figure out the specifics: exact locations for bus stops, crosswalk designs and locations, bike lane configurations, sidewalk improvements and stormwater management solutions. These details matter because they affect how the final design actually works in your daily life.

Timeline and funding

Final design and construction of WSDOT's preferred option for the I-90 interchange will depend on future funding. Later this year, SDOT will begin engaging the community on how to modernize Rainier Avenue South between South Jackson Street and South Walden Street with their levy funded paving project.

Learn more and stay informed

We are committed to transparency throughout this process. Just like the Seahawks' Twelves, your feedback makes a difference. Thanks for helping to make this community driven.

Study webpage

• Visit the project page for the latest updates, detailed information and recordings/presentations from our Advisory Group meetings.
• Email updates: Sign up for Seattle area news and study updates.

Contact Info

Amber Stanley - Community Engagement Lead
Phone: 206-817-8833
Email: amber.stanley@wsdot.wa.gov

GO SEAHAWKS!

Judkins Park and I-90 – choosing the best alternative for the ramps

By: April Delchamps

Finding the right fit for the community

It is that time of year in Washington when choosing the right outfit feels impossible. You leave home layered up with rain boots and jacket. And, an hour later, you are sweating while carrying all that gear around town.

Deciding on a winter outfit can be tricky. Good luck out there, all! Choosing the right street layout changes for a WSDOT project is far more complex. These decisions affect neighborhoods, local businesses and community organizations. At Rainier Avenue South and I-90, they affect everyone who walks, rolls, bikes or drives.

We take this responsibility seriously. We know past decisions have had a big impact on overburdened communities. For every study and project, we must find a balance. We have to work within the physical limitations to find the best access and safest options, while avoiding negative impacts on the community. Learn more about WSDOT’s best practices as it relates to community impacts.

The Judkins Park challenge

The Judkins Park Station – Reconnecting Communities Study demonstrates this careful balance. We are studying how to improve where the I-90 ramps meet Rainier Avenue South. We now have four options, or alternatives, to consider. You could say we are “trying on” these four different alternatives.

The community has played a central role in coming up with these four alternatives. You have shared what you love about your neighborhood and how you want to see it improve. Passionate people in the Judkins Park area have joined us, imagining a new design for these I-90 ramps.

What exists today

Here is what the ramps look like today:

Map of Judkins Park area with the on-ramp and off-ramps.

Our goal is to enhance safety and connectivity for those who walk, roll and bike. This will be even more important when the Judkins Park Link light rail station opens. Like choosing the right winter outfit, we are thinking about benefits and tradeoffs. We want to understand the human experience, as well as what the traffic models predict.

What we are considering

1. Community input

Community feedback is at the center of decision-making. Read our first blog post about this study for more details about what we have heard from the community.

2. Current data and assumptions

We are testing the four alternatives with these assumptions:

• There will be increased transit, biking, and walking or rolling in the Judkins Park area.
• There will be no increase in vehicle traffic.
• Changing the ramps provides opportunities to reduce the number of lanes along Rainier Avenue South, in the study area, from six lanes to four lanes.
  • Important note: A follow-up test will be done to check if the number of lanes at the intersections can be further reduced by using lower traffic volumes along Rainier Avenue South.
• Vehicles cannot turn right on a red light at a traffic signal.

3. Physical limitations

We are balancing these realities:

• We cannot get rid of vehicle access. People need to access social services, schools, work and other activities.
• Community places must stay connected. This includes parks, trails, businesses, schools and services.
• Space is limited. We have to think about things like hills and slopes, stormwater systems, sound walls and other projects (like the Judkins Park Station and RapidRide).

The four alternatives

We have narrowed our options down to four alternatives, or options. Each one has a different way of enhancing safety and connectivity for people walking, biking and rolling. Think of it like trying different outfits. Your warmest coat is the heaviest to carry, and your rain boots might not be ideal for walking long distances. No option is perfect, which is why we are carefully studying how each one may work in real life.

Important note: Our engineers are evaluating each option. They are verifying the number of vehicle lanes, how bus stop areas work and how the intersections are designed. We are sharing what we know so far, and once these options are refined, we will share more.

In every option, we are thinking about how the ramps meet Rainier Avenue South. If we use T-shaped intersections, with angles closer to 90-degrees, vehicles will have to slow down or stop. This means vehicles will not be able to flow freely from the ramps to Rainier Avenue South.

Alternative 1

This option keeps all existing ramps. This allows vehicles to access the Judkins Park neighborhood services and destinations. Here are some other things we are considering for this alternative:

• A single traffic signal or roundabout would be added to Ramp #3 and Ramp #5, and a new traffic signal would be added to Ramp #4. This would force vehicles to slow down or stop. They would not flow freely between Rainier Avenue South and the ramps.
• This option also reduces Rainier Avenue South to four lanes under I-90. Buses would stop in the regular travel lane to pick up and drop off passengers. In this design, buses spend less time pulling out of and merging back into traffic.

A map of Alternative 1. The ramp changes are shown in orange.

Alternative 2

This option closes the westbound I-90 off-ramp to northbound Rainier Avenue South (Ramp #4, shown with red hatching). Here are other things we are considering for this alternative:

• Adding a traffic signal or roundabout to Ramp #5. This would serve vehicles travelling from westbound I-90 to both southbound and northbound Rainier Avenue South.
• A pedestrian signal is added just north of I-90. This would allow people to cross the street at a controlled marked crossing.
• This option reduces Rainier Avenue South to four lanes under I-90. It would use in-lane bus loading, similar to Alternative 1.

A map of Alternative 2. Ramp changes are shown in orange, and proposed ramp removals are shown in red.

Alternative 3

This option is the opposite of Alternative 2. Alternative 3 closes the I-90 westbound off-ramp to southbound Rainier Avenue South (Ramp #5, shown with red hatching). Some other things we are considering for this alternative are:

• Adding a traffic signal to Ramp #4. This will serve vehicles travelling from westbound I-90 to both southbound and northbound Rainier Avenue South.
• A traffic signal or roundabout would also be added to Ramp #3. This would allow people to cross the street at a controlled marked crossing.
• This alternative also reduces Rainier Avenue South to four lanes under I-90. It would use in-lane bus loading, similar to Alternative 1.

A map of Alternative 3. Ramp changes are shown in orange, and proposed ramp removals are shown in red.

Alternative 4

This option makes the most dramatic changes. It would close both the westbound off-ramp (Ramp #4) and the eastbound on-ramp (Ramp #2) (both shown with red hatching). The vehicle movements served by Ramp #4 would be added to Ramp #5, and the vehicle movements for Ramp #2 would be added to Ramp #3. Other elements of this alternative are:

• A single new traffic signal or roundabout would serve both Ramp #3 and Ramp #5, north of I-90.
• A pedestrian signal is added just north of I-90. This would allow people to cross the street at a controlled marked crossing.
• This alternative requires six lanes under I-90. There would be four vehicle lanes and two bus lanes. The buses would load in their own lane, which requires the buses to merge back into traffic.

A map of Alternative 4. Ramp changes are shown in orange, and proposed ramp removals are shown in red.

What’s next

As winter continues, Seattleites will continue the daily winter outfit debate. Meanwhile, our engineers will be using special software to review each alternative. They will be looking for a sweet spot. They want to enhance safety and comfort for people who walk, roll, and bike, without making it harder for drivers.

A graphic showing our study process and how community engagement is incorporated into our decision-making process.

Where we are in the study

We are using a clear process for our study. We want to improve access to the light rail station and reconnect the community. We are currently in the middle of Step 4, shown below.

Here's how it works

See the graphic on the right for more details on the study process, the questions we’re asking at each step, and how we’ll arrive at the final result.

After step 4, analyzing the four alternatives, we will talk about the results. We'll share these in a future blog post.

Throughout this whole process, we are working closely with both our Advisory Group and the community to get their input.

Learn more and stay connected

We are committed to transparency throughout this process.

Study webpage

Visit the project page for the latest updates, detailed information and recordings/presentations from our Advisory Group meetings.

Email updates

• Sign up for Seattle area news and study updates.

Contact Info

Amber Stanley - Community Engagement Lead
Phone: 206-817-8833
Email: amber.stanley@wsdot.wa.gov

Re-connecting communities: How Judkins Park is Reshaping its I-90 Ramps

By: April Delchamps

The opportunity to shape Judkins Park

Aerial view of Judkins Park and the surrounding neighborhood.

A new light rail station is opening in the Judkins Park neighborhood soon, which is going to change how people get around. More people will walk, bike and roll in the area. To prepare for this shift, we are looking at potential improvements where the I-90 ramps meet Rainier Avenue South.

The I-90 Judkins Park – Reconnecting Communities Study is a chance for the community to help shape how people travel in their neighborhood. The study brings together community voices, transportation experts and creative design to find better ways for people to travel on Rainier Avenue South at I-90.

What we are studying and why

Anyone who has walked, biked or rolled through Judkins Park has dealt with fast-moving vehicles getting on and off I-90 ramps at Rainier Avenue South. A 2018 study done by the Seattle Department of Transportation recommended that we improve these on- and off-ramps. When the new light rail station opens, even more people will use the I-90 interchange. These travelers might be traveling by foot, bike, adaptive device or many other ways. We are considering ways to improve safety at all five I-90 on-ramps and off-ramps at Rainier Avenue South. Our goals are to:

• improve safe travel for all—particularly for pedestrians and cyclists
• strengthen community connectivity
• improve access to the Judkins Park Link light rail station

Map of the Judkins Park area with the I-90 ramps endpoints shown as orange dots.

Advisory Park members represent many voices

No one knows a neighborhood better than the people who work, live and spend time there. The Advisory Group was created to include these voices—people who have lived here a long time and newcomers; business owners and people who commute; homeowners and renters; people who walk, roll and bike; families; and community advocates. The group includes people from local schools, community organizations, small businesses, advocacy groups and transportation agencies (City of Seattle, King County Metro and Sound Transit).

Advisory Group role

We work together with the Advisory Group to talk about changes that can be made to improve safety and efficiency of the I-90 ramps. The Advisory Group meets regularly through mid-2026.

Input from this group, and the community in general, helps us understand the community’s needs and priorities as they access the light rail station and get around the Judkins Park area.

Learning from past feedback

Judkins Park has been part of several transportation studies and community engagement efforts. We collected helpful feedback for this study in 2024 and plan to keep asking the community for input. We want to learn from past studies, while also making sure we have the most up-to-date information from the community for this work.

What the community has said so far

People touring the Judkins Park area as part of the Seattle Neighborhood Greenways Walking/Rolling Tour in 2024.

We talked with many people during Advisory Group meetings, events, surveys and listening sessions. Here is what we have heard:

Key community priorities:

• Getting around: people want to take the bus, walk, roll or bike to safely and efficiently get around Judkins Park and to the light rail station.
• Improvements to sidewalks and crosswalks : People want sidewalks that are not broken, disconnected or missing; crosswalks that are easy to find and use; to stay dry rather than get splashed on sidewalks; and more lighting.
• Traffic issues: People want drivers to slow down, stop at crosswalks and drive more carefully; better visibility for drivers to see people, especially when it is dark or raining.
• Noise and air pollution: People want less noise and cleaner air.
• Getting around for everyone: People want better access for people who walk, roll and bike; better crossing solutions for pedestrians who are visually impaired; solutions that also consider people who need to drive because other options are not accessible to them; noting that people have different, important needs that may require different solutions.
• Plan carefully: People want careful planning to minimize how closing or changing roads may affect people.

We are including this input to guide this study. We are studying ways to:

• make walking, rolling, biking and taking transit more comfortable
• reduce conflicts between traffic and pedestrians and people who bike
• create shorter routes for pedestrians and bikes
• get vehicles to drive slower

SDOT's near-term improvements

SDOT, in coordination with us, has made improvements to help with concerns now, while we work on long term solutions in this study. SDOT finished construction this year, and you can see the improvements in the community.

Where we are in the study

Our study follows a clear process to find the best solutions for reconnecting our community. Here's how it works:

Step 1: What problems are we trying to solve? We listen to the community and Advisory Group to understand what needs to be fixed or improved.

Step 2: How do we decide what's most important? Community and Advisory Group input helps us figure out which benefits and impacts matter most.

Step 3: What are our options? We work with the community and Advisory Group to come up with different ways to make improvements.

Step 4: Which options work best? We review each option with community and Advisory Group feedback to see which ones meet our needs.

Step 5: How can we make these options better? We use more feedback to improve and select the best options.

Step 6: Any final thoughts before we choose? We get final input from the community and Advisory Group to make sure we've got it right. We also create a draft report of our findings.

Step 7: What did we choose and why? We finish our study report and begin designing the improvements we recommend.

The Advisory Group for the I-90 Judkins Park Station study started in late 2024. Throughout this whole process, we are working closely with both our Advisory Group and the community to get their input.

We are currently looking at different options for improvements and will share more details about what we are learning in our next blog post.

Learn more and get involved

Study webpage

Visit the project page for the latest updates and detailed information:

SDOT study webpage

Learn about complementary near-term improvements.

Stay Tuned for More Opportunities to Participate

We are committed to keeping the community involved through this process. Watch for announcements about more opportunities to share your thoughts. Sign up for Seattle area news and study email updates.

Contact Info

Amber Stanley - Community Engagement Lead

Phone: 206-817-8833

Email: amber.stanley@wsdot.wa.gov

Diverging from the norm to deliver a diamond

Update: July 2025: Diamonds in the rough

The eight-day closure of State Route 18 July 17-25 will allow the switch to a diverging diamond at the interchange.

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By David Rasbach

Eight-day closure of SR 18 will build northern end of diverging diamond

They say diamonds are formed under pressure, and building the diverging diamond interchange at I-90 and SR 18 has been no exception. We know the closures, detours and delays have been tough. But all the time, planning and pressure has gone into shaping something that will last.

From July 17 to July 25, crews will complete the northern half of the diverging diamond interchange at I-90 and SR 18. This work requires another full closure of SR 18 in both directions at the I-90 interchange. It’s longer than the June closure because there’s more work to do, but when the road reopens on Friday morning, July 25, people will begin using the new diverging diamond configuration.

During an eight-day closure of SR 18 under the I-90 bridges, crews will build out the northern end of the new diverging diamond. When we reopen July 25, traffic will be shifted into the new configuration.   

SR 18 will be fully closed in both directions at the I-90 interchange. This closure will be in effect from 9 p.m. Thursday, July 17, through 5 a.m. Friday, July 25. No traffic will be allowed under the I-90 bridges during this time.

July 17-18 will include rolling slowdowns on I-90 and 10-minute traffic holds on SR 18 and Snoqualmie Parkway as crews stripe ramps and set the stage. As before, emergency responders will be allowed through the work zone. We’re working with freight partners to help them plan ahead and avoid using local roads as detour routes.

What’s happening during the closure?

Crews will complete a major phase of work on the northern part of the new interchange, including:

• Install drainage and electrical crossings
• Build concrete islands and curbing
• Set and program new traffic signals
• Tie in the new I-90 on-ramps
• Stripe lanes, install signs and switch to the new traffic pattern

This work compresses what would normally take months into a single week, minimizing long-term disruptions and lasting improvements to the corridor.

Detour and access information

While mainline I-90 will remain open, traffic using on- and off-ramps will be restricted:

• Eastbound I-90 off-ramp traffic can only turn right (south) onto westbound SR 18
• Westbound I-90 off-ramp traffic can only turn right (north) onto Snoqualmie Parkway
• No left turns will be allowed from either off-ramp
• Eastbound SR 18 traffic must detour via eastbound I-90 and loop around
• Southbound Snoqualmie Parkway traffic must detour via westbound I-90 and loop around

During the July 17-25 closure of SR 18, you can detour using eastbound and westbound I-90 and loop around at nearby interchanges – exit 20 (High Point Way) or exit 22 (Preston/Fall City) to the west of SR 18 or exit 27 (Southeast North Bend Way) east of SR 18 – to reach your destination.   

Maintaining access: Emergency responders will be allowed through the SR 18 work zone under the I-90 bridges during the closure.

Freight advisory: Freight haulers heading westbound on I-90 should plan ahead:

• Use Exit 22 (Preston/Fall City) to loop back to westbound SR 18
• Or continue west on I-90 to southbound I-405

Please do not use Snoqualmie or Issaquah city streets or Issaquah-Hobart Road. These streets are not suitable for semi-truck traffic.

Westbound I-90 freight traffic should either use exit 22 (Preston/Fall City) to loop back to SR 18 or continue on westbound I-90 to southbound I-405. Issaquah city streets and Issaquah-Hobart Road are not suitable for semi-trucks.   

Full detours will use:

• Exit 20 (High Point Way) or exit 22 (Preston-Fall City)
• Exit 27 (Southeast North Bend Way)

We expect delays, especially during peak travel times. Please plan ahead, leave early and consider alternate routes if possible. Real-time traffic updates are available via the WSDOT app and travel map.

People trying to reach Snoqualmie during the closure of SR 18 should use eastbound I-90, loop around to westbound I-90 at Southeast North Bend Way (exit) 27 and exit to SR 18/Snoqualmie Parkway.

During the closure of SR 18, people coming from Snoqualmie Pass will have to follow a detour to reach westbound SR 18, while people heading from eastbound SR 18 toward the pass can follow their normal route.

During the closure of SR 18, people coming from Snoqualmie and heading to Maple Valley or over Snoqualmie Pass will need to use westbound I-90 and loop around at the Preston or High Point interchanges.

During the closure of SR 18, people coming from south of the I-90/SR 18 interchange who need head west on I-90 will need to use eastbound I-90 and loop around at Southeast North Bend Way.

What’s next

Opening the diverging diamond marks a major milestone in the I-90/SR 18 interchange project.

Work still remains, as we’ll need to return in the next few weeks to add a top layer of asphalt throughout the diverging diamond, including the ramps. We’ll be back a few weeks after that for final lane striping. We’ll announce the details for that work once it’s finalized.

Though the diverging diamond will be open, it will not fully function as designed to allow traffic to flow until we complete widening SR 18 to two lanes in each direction south of I-90. The project will wrap up that work later this fall, and that’s when we expect you’ll see reduced congestion at this busy interchange. That’s when this diamond in the rough will be ready to shine.

Once complete later this summer, the new I-90/SR 18 diverging diamond interchange will improve traffic flow, reduce congestion and increase safety through one of the state’s busiest interchanges.