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In May 2015, the City Council and the Sound Transit Board of Directors agreed to a comprehensive amended Memorandum of Understanding (MOU). It ensures the two agencies will coordinate and collaborate during the design and construction of East Link. This MOU includes general and specific mitigation efforts to address construction impacts to roads, neighborhoods and parks. Exhibit O of the amended MOU reflects the mitigation for the East Link light rail project.

Noise Mitigation

The City of Bellevue is the first jurisdiction to apply a local noise code to light rail operations and was faced with a challenge in how to apply its regulations to this particular operation. In addition to operational noise, construction noise needed to be addressed.

Bellevue’s Noise Control Code

Bellevue’s Noise Control Code (Noise Code) regulates and establishes permissible noise levels based on the type of land use (e.g. residential, business or commercial). The code also sets daytime noise levels in residential areas at a maximum of 55 dBA (decibel level) and nighttime (between 10 p.m. and 7 a.m.) at a maximum of 45 decibels. Construction noise is allowed between 7 a.m. and 6 p.m., Monday through Friday and 9 a.m. to 6 p.m. on Saturday, but is prohibited beyond these hours, on Sunday, and on certain holidays. The Noise Code does contain exemption provisions.

Requests for “extended work hours” (permission to work outside of these windows) are routinely requested for commercial projects, and are granted in consideration of special needs for the project.

Approved Expanded Exempt Hours Permits for East Link light rail construction

The City has approved the following Expanded Exempt Work Hours Permits. For more detail, go to the Noise Mitigation page 

East Link Operational Noise and Mitigation

The East Link light rail facility is a permitted use under Bellevue’s land use code and its construction (including the guideway system and supporting infrastructure) is governed by the Design and Mitigation Permit (D&M Permit) process. A D&M permit has been issued for:

Noise from the operation of light rail is expected from a number of components of the system:

  • Light rail vehicle operation noise: The noise of a train travelling by a location including wheel/rail interface, train-mounted warning devices, and track crossovers.
  • Stationary noise: The noise of the safety systems associated with the train including pedestrian-audible warning systems at stations, station public address systems, electrical transformers, and traction power substations.

The City’s Noise Code anticipates regulating noise from stationary noise generators but includes exemptions for safety features.

Because the City’s code does not take into account how to deal with ambient noise levels above the allowed threshold, and additionally is fashioned to deal with stationary noise sources, the City engaged a consultant to assist the City in determining how to apply the code to Sound Transit’s operational noise, and determine the appropriate mitigation. The City’s consultant primarily reviewed studies conducted by Sound Transit to ensure that industry best practices were followed in developing the noise models, interpreting the outcomes and fashioning mitigation.

These studies concluded the level of ambient nighttime noise in South Bellevue exceeds what the City’s code allows. Ambient noise is the level of typical existing noise from all sources. In the South Bellevue area ambient noise is due to everyday traffic noise from I-405, I-90 and 112th Avenue NE. The city’s consultant reviewed Sound Transit’s reports and proposed additional mitigation, such as extensions in length and height of sound walls, maintenance of rails and train vehicles, and nighttime reduction of any audible warnings (such as bells or announcements). This additional mitigation is designed to ensure that East Link’s operational noise does not increase the ambient noise levels in residential areas and is addressed in the E320 D&M Permit.

Additionally, the city is requiring monitoring of the light rail system to ensure operating sound levels are consistent with projections made through the environmental and permit review process. This monitoring ensures that these sounds do not become louder over time because of lack of maintenance.

Traffic Mitigation

The city is aware of the importance of Bellevue Way as the south entrance to and from the city. While no large-scale construction project of this magnitude is without disruption, requirements for the flow of traffic along Bellevue Way during construction are of paramount importance. 

Bellevue Way

The 2015 MOU requires that two lanes of traffic on Bellevue Way must be maintained in the peak direction at all times. This results in maintaining existing travel lanes in the direction necessary during peak commute times, meaning two lanes northbound, into Bellevue during the morning commute, and two lanes southbound, toward I-90, during the evening commute. Lane closures outside of peak travel times (7-10 a.m. and 4-6 p.m.) and full weekend closures will also be necessary for certain work. It is possible that more than 20 full weekend closures will be needed over the four-to-five-year construction timeline.

In response to the public desire to avoid having audible signals at rail/road crossings on Bellevue Way at Southeast Fourth Street and Southeast First Place, it was determined that the streets would be permanently closed. Beginning in the spring, the Southeast First Place entrance to Surrey Downs will be permanently closed. The permanent closure of Southeast Fourth Street is expected in spring 2017.

South Bellevue Park and Ride Closure

The South Bellevue Park and Ride (P&R) closed May 31, 2017; Sound Transit plans to reopen it in fall 2021. Per the 2015 amended MOU, the Sound Transit must implement, in consultation with the city, “alternate parking and transit access” for those commuters who use this P&R 60 days prior to the closure.

When the South Bellevue P&R (and Overlake Transit Center P&R closed), alternate parking was established for commuters who use both lots. Alternate Commuter Parking information

Sound Transit’s 550 Route (Bellevue to/from Seattle) will continue to serve commuters during East Link construction but will be eliminated once the East Link extension is in full operation which is anticipated in 2023.

Neighborhood Traffic Mitigation for South Bellevue Segment

In spring 2016, a neighborhood volunteer committee was formed to work with city staff to develop a traffic mitigation plan to address the long-standing concern of increased neighborhood traffic during light rail construction on Bellevue Way Southeast and 112th Avenue Southeast. Neighborhood Traffic Mitigation Committee (NTMC) members represented the neighborhoods of Bellecrest, Enatai, Surrey Downs and the Village of Beaux Arts.

Pilot Modifications Map

In Sept. 2017, weekday, afternoon turn restrictions were implemented at Southeast 16th Street and 108th Avenue Southeast and at Southeast 16th Street and Bellevue Way Southeast. The intent of the turn restrictions was to decrease evening commuter traffic in an area known to have higher traffic volumes while light rail construction was occurring on Bellevue Way Southeast and 112th Avenue Southeast. Based on community input to the turn restrictions, adjustments were made in Jan. 2018.

Traffic volume studies have shown that the turn restrictions have been effective in reducing evening commuter traffic. Although the program was introduced as a pilot, the city has determined to permanently retain the turn restrictions based on their effectiveness, community support and the transformation of 108th Avenue as a priority bike corridor that connects to downtown and the I-90 trail.

Visit the South Bellevue Traffic Mitigation webpage for details.

Park Mitigation

The final East Link alignment selected by the Sound Transit Board is adjacent to Mercer Slough Nature Park and Surrey Downs Park. Both city parks will be impacted by the East Link project and there are mitigation plans in place to offset those impacts. These impacts and conceptual mitigation have been part of the discussions around this project since preparation of the Draft Environmental Impact Statement (EIS), Final EIS and federal Record of Decision for the project, issued in 2011.

Mercer Slough Nature Park

Enhancements and mitigation to Mercer Slough Nature Park include over six acres of wetland and wetland buffer restoration within the park and planting more than 2,800 trees to offset the 691 being removed for the project. Additionally, six acres were added to the park through acquisition of private property just south of the Mercer Slough Environmental Education Center. Following construction of East Link, a new building and parking area will be opened near the Winters House providing park restrooms and u-pick blueberry and seasonal farm-fresh produce sales. These will be connected to 700 linear feet of new boardwalk trail. More about tree mitigation in Mercer Slough Nature Park.

Surrey Downs Park

Once the East Link alignment was finalized, it was necessary to update the city's Surrey Downs Park Master Plan (adopted in 2009) because of the loss of a portion of the Surrey Downs Park along 112th Avenue Southeast frontage. Through a public involvement process, the vision for the park is now to be more neighborhood-focused and will include open grass areas, playgrounds, picnic shelters and a pedestrian “overlook” integrated into the trail system.

Noise studies were conducted and sound mitigation was included in the 112th Street park frontage improvements and the Parks Department will work with adjacent property owners to construct perimeter fencing along the parks boundary with neighbors.

Additionally, vehicle access will be off of Southeast Fourth Street (and no longer 112th Avenue). The council adopted the Surrey Downs Park plan update in November 2015 (park plan schematic). It is expected the Surrey Downs Park improvements will not be initiated until after Sound Transit completes its 112th Street frontage improvements. The Park opened in summer 2019.