Mercer Island Transit Interchange

We believe you may be referring to an article in a recent City E-Newsletter, not directly related to the Transit Interchange Project.

Each year, the City adopts the Six-Year Transportation Improvement Program (“TIP” -- see our TIP 2020 page) which is a planning tool to identify specific projects that serve to maintain, preserve, and maximize the use of the roads and trails. Budget policy prioritizes reinvestment (i.e. preservation and maintenance projects), before constructing new facilities such as additional sidewalks and lighting. The TIP has a “New Construction Project” category that currently includes projects with new sidewalks and improved lighting. 

Unfortunately, due to limited funding resources and competing project needs, these projects are not scheduled until 2022.  If you would like the City to consider additional project locations, we recommend submitting public comment during the next TIP process – scheduled to begin in the Spring of 2021.

Sound Transit has provided the following information about daily boardings (i.e. number of people getting onto light rail) at the Mercer Island Station: “The 2011 FEIS included a projection of 1,500 daily boardings at the Mercer Island station in 2020 and 2,000 daily boardings in 2030. A more recent projection from 2016 included an approximate 4,200 daily boardings for the current year (this is an estimate of the ridership if East Link was operational in 2016 and all ST2 projects were complete). This number does include passengers transferring from buses.”

Sound Transit notes that “While Metro does not estimate future bus ridership at the individual bus trip or route level, the best estimate stems from the pre-Settlement Agreement East Link FEIS Addendum (April 2017) that states the following: ‘With the 77th Avenue SE Configuration, approximately 1,300 pedestrians in the busiest AM peak hour, (1,050 from bus transfers and 250 from the park & ride lot) would cross N. Mercer Way between the I-90 bus route stops located on the north side of N. Mercer Way (NMW) and the light rail station. This equates to 32 pedestrians per signal crossing cycle in the busiest AM peak hour.’” *Note the busiest AM hour is projected to fall between 6-9am on weekdays.

Sound Transit emphasizes that it’s important to remember these are projections that fluctuate as more data and information become available. Sound Transit projects ridership using various assumptions that reflect best available information such as regional employment and population forecasts, which provide information about a specific period in time. While this information gives ST a rough idea of what it can expect in terms of ridership, there are other assumptions that can affect these numbers.

In addition to transit integration at the Mercer Island Station, Sound Transit will also connect bus passengers to light rail at the S. Bellevue Station. While it does not yet know the exact routes and number of buses at that location (just like at Mercer Island, Metro and Sound Transit will undertake a public outreach process 18-24 months in advance of East Link opening to determine the exact route configurations), it has stated that there will be 6 bus layover spaces, 3 active bus bays and a paratransit zone.

Thanks for your comments. In response to your two questions:

1) There will be an estimated 4200 boardings (people getting on the train) during commute days.  Some of these people will come from the Park-and-Ride, some will be MI residents walking, biking or getting dropped off at the station, and some will arrive by bus from the Eastside and transfer to the East Link station.  Those people arriving by bus and from the P&R will cross North Mercer at 80th to catch the train.  On the return trip from Seattle, those passengers transferring back to buses will be picked up on the south side of N Mercer Way, and will not need to cross the street again.  The main group of people making afternoon crossings at N Mercer Way will be those walking over to the Park & Ride. The greatest impact to the crosswalk at North Mercer Way/80th Ave SE will be in the morning peak hours between 6-9am.

The 77th Ave SE entrance to the MI Station is designed to serve pedestrians, bicyclists and local drop-offs, and crossings at North Mercer Way will likely be from local foot and bicycle traffic.  Bus passengers will disembark near 80th and would reasonably walk the shortest distance to the 80th Ave entrance, and are not anticipated to walk the extra distance to reach the 77th Ave entrance to the station.

2) Staff has preliminarily explored the possibility of a pedestrian bridge across N Mercer Way.  Pedestrian bridges get mixed reviews in terms of requiring usage by the public and other considerations, so this is not a simple solution. The City continues to explore options to address community safety concerns in this area.

Metro was not a party in the lawsuit between the City of Mercer Island and Sound Transit over the closure of the I-90 bridge center roadway. As a result, Metro is also not a party of the Settlement Agreement that resolved the lawsuit. The only parties to the Settlement Agreement are the City and Sound Transit.

Metro operates buses for Sound Transit, and Metro is currently claiming that the 77^th Ave SE Configuration (that the City and Sound Transit agreed to in the Settlement Agreement) will not work for Metro’s operation of Sound Transit buses. Metro has asked for changes to the 77^th Ave SE Configuration. Under the terms of the settlement agreement, the City and Sound Transit are required to consider modifications to the agreed-upon Configuration based on Metro’s operational needs.

There isn't going to be any new structure that can be defined as a "bus station."  The transit interchange is basically just curb space where buses will pull up in front of the existing Park & Ride to allow passengers to connect to the future light rail service (opening in 2023). A roundabout will be constructed to allow the buses to turnaround more easily at 77th Ave and North Mercer Way. There may be a few additional bus shelters added. The major construction that you see in this area today at street level is to build the entrances to the East Link light rail station. As design work advances on the roundabout, more details will be posted here. 

Mercer Island Station is an important part of the East Link light rail system.  Metro has already planned to completely fill the capacity for bus transfers at South Bellevue Station and cannot plan for additional routes there. Additionally, direct service to Mercer Island avoids out-of-direction travel for Issaquah/Eastside buses, and provides safer, quicker connections to/from the I-90 HOV lanes, resulting in faster bus travel times and discouraging Eastside drivers from parking on Mercer Island to reach Link light rail.

The 77th Avenue SE Configuration as approved in the Sound Transit Settlement Agreement includes the construction of a new roundabout at the intersection of 77th Avenue SE and North Mercer Way, replacing the current three-way junction (or T-intersection) at this location. The roundabout construction will require Sound Transit to acquire two private properties to the north of the roundabout. Learn more about its property purchasing policies and procedures.

1.  What are the neighboring houses going to see--what is it going to look like from the neighborhood side--once the roundabout is constructed?

The transit interchange is still in the early design stage and the design of the interface between the proposed roundabout and the neighborhood to the north has not been determined. For reference, the houses adjacent to the North Mercer Way and 77th Ave intersection are much closer today than any house will be to the future roundabout.

Although the existing shrub hedges in the landscaped areas north of the North Mercer Way/77th Ave SE intersection would likely be removed for construction activities and revised ADA compliant trail connections, new landscaping and fencing will replace those removed. Sound Transit intends to work closely with the City of Mercer Island as the design progresses to provide appropriate buffers and screening between the roundabout/transit interchange and the neighborhood to the north.

2.  Is the current pedestrian cut-through going to remain?

The proposed transit interchange is still in the early stages of design and connections to the adjacent neighborhood have not been fully designed at this point. However, the conceptual plan envisions a connection of some sort between the I-90 Trail and the north neighborhood at least to the same scope of what exists today.

3.  What is the planned use for the remainder of the two lots and what will they look like? (I'm talking about the lots where the two houses are--the houses that will be torn down)

Plans for the property not disposed to the City of Mercer Island for the roundabout are unknown at this time (Sound Transit to retain ownership of this remaining property). However, per the conceptual design, new roadway features will allow for a number of additional landscaped areas; the entire north side of the roundabout will have an approximately 5-foot planter, allowing for the installation of new (or existing) trees/shrubs to separate the I-90 Trail and the proposed roundabout from the neighborhood to the north. Sound Transit intends to work closely with the City of Mercer Island on redevelopment that is compliant with local zoning codes and development plans.

4.  What will be done to reduce the impacts (sights, smells, sounds) of the roundabout and increased traffic?

The proposed roundabout will not result in an increase in traffic; in fact, the total number of buses on Mercer Island will not exceed existing numbers and will be reduced by almost half due to the Settlement Agreement. The proposed roundabout was analyzed during the environmental review process.

5.  Will there be a sound wall and/or replacement landscaping? Assuming there is a sound wall, where will it be in relation to the two lots?

The transit interchange is still in the early design stage and no decisions have been determined at this time. Sound Transit intends to work closely with the City of Mercer Island as the design progresses to provide appropriate buffers and screening between the roundabout/transit interchange and the neighborhood to the north.

6.  How many buses will be laying over during the afternoon peak period? Where will they be laying over? --Please confirm that there are no plans to use part of the two lots as a bus parking or layover area.

The exact number of buses laying over during the afternoon peak are not known at this time. Metro will be updating its service plan for this area much closer to the start date of East Link revenue service in 2023. Per the proposed configuration, buses will lay over on both the north and south sides of North Mercer Way to the east of the proposed roundabout; the amount of curb space available for buses would allow up to 4 buses laying over at any given time. There are no plans to use the two lots for additional bus layover or bus parking areas.