Bridging the Trail Gap Over I-405

King County’s regional trail network is a great way to beat the traffic and ride to work, but soon a new bridge on the Eastside Rail Corridor (ERC) will allow you to literally ride, walk, or run over the traffic.

In early 2020, we will kick off a partnership with the Washington State Department of Transportation (WSDOT) to build several new paved miles of the ERC trail including a critical bridge over Interstate 405 in Bellevue. This project is scheduled to break ground by spring 2020, with the goal to be complete in 2021.

Miles of New Paved Trail South of I-90

We hope runners, walkers, and bikers will love the new wide paved ERC trail coming just south of I-90. WSDOT will expand I-405 as part of the I-405 Renton to Bellevue Widening and Express Toll Lanes Project. This will require the removal of the existing Lake Loop Trail. To compensate for the removal of the existing trail, WSDOT will construct 2.5 miles of paved ERC trail south of I-90 between Coal Creek Parkway Southeast and Ripley Lane (near the VMAC Seahawks training facility).

This section will be the first paved section of the ERC owned by King County. The trail will be 12 feet wide with a two-foot gravel shoulder on one side, and six feet of gravel on the other. If you are a walker who would like some more space between you and cyclists you will enjoy this wide gravel shoulder.

In order to construct this 2.5 miles of paved trail, we will have to temporarily close down the existing gravel ERC trail in this segment, but don’t worry. The Lake Loop Trail will remain open until the paved ERC trail is complete so you will still be able to pedal or run on a trail in this area.

In partnership with WSDOT, two main main trail sections will be built.

New Bridge Over I-405

North of I-90 WSDOT will also be constructing a new trail bridge over I-405 near the Mercer Slough. This bridge will be near the location of the former Wilburton train tunnel that once served as a freight train crossing over the southbound lanes of I-405. This tunnel was demolished in 2008 after train operations had stopped and WSDOT needed to expand the freeway.

By the end of 2021 trail users will be able to take this new I-405 bridge and continue north across the historic Wilburton Trestle.

I-405 trail overpass.

Connecting these New Trail Sections

How will runners or bikers connect between the new I-405 bridge and the new trail south of I-90? Until the completion of a future trail bridge over I-90 the route follows Lake Washington BLVD and 118th Ave SE for a mile between Coal Creek Parkway and Southeast 32nd Street in Bellevue. When funding becomes available we look forward to completing this trail connection all the way from Renton to Bellevue.

15 thoughts on “Bridging the Trail Gap Over I-405

  1. Is there going to be any access to the trail on the east side of 405 between the new 405 trail bridge crossing and the Wilburton Trestle, without having to use the access from Holmberg Mechanical Contractors new site?

    1. Thank you for the question, currently Parks does not own any property in the area you are referring to which would allow access. But we are always keeping an eye out for opportunities to increase access to our trails.

  2. I hope the design of the bridge over I-405 does not exclude any future addition of rail in a mixed mode facility. Parameters such as overall width and radius of curvature should accommodate rail.

  3. Can someone comment on the non-viability of the existing rail bridge over I-90? In Minnesota and Pennsylvania they use these all the time. I fail to see the need for a new bridge and I think it would be good for someone to explain it to those of us scratching our collective heads on why we would get rid of a perfectly good (and strong) rail bridge to use.

    1. Hi Scott, we fully intend to retrofit the existing I-90 steel bridge for the trail when funding becomes available. We are looking forward to making this key connection.

  4. How about doing something for residents to the north who have a dirt/gravel trail that is dusty in the summer and muddy and dark in the winter? I.e the “Cross Kirkland Corridor.” There is no timeline or funding for doing anything with it and it will remain dirt and rocks without leadership and initiative.

    1. King County Parks works very closely with the City of Kirkland who owns and manages the Cross Kirkland Corridor “CKC”. The ultimate vision for the ERC corridor is to have a continuous paved trail running the entire length. We don’t have a timeline for when we hope to have this all accomplished but we are very excited to making some key connections including this partnership with WSDOT.

      1. Thanks KCP for the response. My concern is that if you actually try to get any details on the timeline or funding for the CKC, there is NOTHING to be had. The city of Kirkland has put out a “Master Plan” for the trail that looks amazing, but they published it many years ago, and it has remained dirt and rocks ever since. Outside effort would be greatly appreciate to get the ball rolling on doing something with the trail. As it stands, cyclists in Kirkland have NO safe, efficient routes through the city. If Kirkland and King County are serious about providing ATTRACTIVE alternatives to SOV travel, safe, efficient, and convenient bike travel options seem like a no-brainer.

      2. I am new too cycling and started cycling to work and for fun on weekends. I searched what are the options around the area and was excited to learn about Kirkland Master bike to paved trail across Kirkland.
        While gravel trails maybe be good enough for walking/running, for road cyclist like myself it is not much of use..(unless you have gravel bike or similar).
        I completely agree with Leo Gilbert that having master plan released years ago with not much progress since interim trail opening 5 years ago, it doesn’t give me much hope that it will ever be complete….
        The actions (or lack of) speaks more than fancy promises. I wish our officials were serious about promoting healthy lifestyles, reduction of emissions and taking a few car off the road at the same time.
        it’s very discouraging…
        To top this, I also learnt about the Eastrail project to extend all the way to Snohomish. Another great project (“idea”), but now I am fear that I will only “see” it completed in my dreams…The project has no timeline just like the Kirkland Corridor trail…

  5. Great! Now please address the northern part of the ERC, the “CKC,” or “Cross Kirkland Corridor.” It is a dirt and gravel trail that is dusty in the summer and muddy and dark in the winter. Currently, cyclists have NO protected bike lanes through Kirkland. Improving the CKC as you are doing for the rest of the ERC would do wonders for making Kirkland more accessible by bike.

    1. Hm, I live in Kirkland, use the CKC and cannot really agree that it is “dirt and gravel trail”. Sounds like you are more expereinciugn an MTRB track than the well prepared and wide gravel path that it is.
      The CKC can be used year round w/o issues – but there are also protected bike lanes through out Kirkland. Lake Washington Blvd, Lake Street, Market Street, Juanita Drive, 98th/100th Avenue, 124th Av, etc.
      For a city in the US, we have excellent biking facilities. That said, in a perfect world the ERC/CKC should be a light rail path from Renton all the way up to Snohomish, and have a paved bike trail in parallel.

      1. (1) I think you and LEO GILBERT have different definitions of ***protected bike lanes***. I think of a protected bike lane as have a solid barrier between the bike lane and the car lane such that a car would get damaged if it tried to cross into the bike lane. I avoid bike lanes that are separated from car lanes with a painted white line. One texting idiot that crosses the painted line and you’re dead or in a wheelchair for life.

        (2) I ride the “CKC,” or “Cross Kirkland Corridor” often. Pedestrians hate the dust bicycles make in the summer. It can get really bad.

        (3) In a torrential downpour my wheels kick up the sand and grit and gets all over my chain and gears and shoes and the inside of my pant legs and covers my tires, all of which I have to deal with before I can take my bike into my home.

        I love the CKC. While cars on 405 are honking at each other, I’m saying hello to happy pedestrians that are out walking their dogs. This is not an exaggeration.



  6. Thank you for all the work in making this happen. The walking and biking options opened by the Wilburton crossing will be significant.

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