The go-to source for information on SR 520 construction
During SR 520 construction, work will occur at several locations in Seattle, including the Montlake, Madison Park and Roanoke areas and along the I-5 express lanes. Currently there are two active construction projects, the Montlake Project and the SR 520/I-5 Express Lanes Connection Project. Check our Construction Map for information about what's happening now or in the coming weeks.
Click on any topic below to learn more about potential effects. For each topic, learn:
You can also view current Montlake Project work activity via our construction cameras.
Our community construction management plans, linked at the bottom of this webpage, detail the actions our contractor crews follow to limit the effects of construction on nearby neighborhoods and travelers within the highway corridor.
During SR 520 construction, our contractors perform a variety of construction activities. Each activity uses different types of equipment and creates different levels and kinds of noise. Each week, we publish a report featuring nighttime noise data and complaints.
Working at night and on weekends eases weekday traffic congestion on SR 520, I-5, Montlake Boulevard and local streets, particularly when lane closures or detours are required. We are always looking for opportunities to reduce nighttime effects on the neighborhood, and we will schedule noisy activities during the day whenever possible.
WSDOT is committed to minimizing activities that would result in noticeable vibrations, but some activities necessary for construction are likely to cause vibrations. Construction activities that may cause noticeable vibrations include pile driving, constructing drilled shaft foundations and demolishing existing structures.
Certain construction activities may affect air quality in the vicinity of the construction site. Some of these activities include truck traffic, asphalt paving, earthmoving, and demolition.
SR 520 construction will cause temporary, and in some instances, permanent changes to views and the visual context of the SR 520 roadway within the existing landscape. Montlake Project construction activities will affect views of and the visual context of the Montlake area and Lake Washington. Construction on the SR 520/I-5 Connection project will affect views along I-5 between the SR 520 and Mercer Street interchanges. Some construction work will occur during the night and will require lighting to work safely. During the winter months (November through March), there may be increased work-zone lighting at the beginning and end of the workday due to decreased daylight hours.
SR 520 construction activities will cause traffic and transportation disruptions due to adjustments in existing roadways, temporary closures, detours, and changes to pedestrian and bicycle access through the area. Additionally, construction equipment and activities may occupy part of the roadway and construction truck traffic will be present on the highways and local roads.
Conditions on the SR 520 mainline will remain similar to previous conditions, with two general-purpose lanes in each direction between Montlake and the floating bridge. These projects will require some short-term closures of SR 520 and I-5, as well as nearby on- and off-ramps. Construction activities on major city arterials like Montlake Boulevard and Lake Washington Boulevard will require lane shifts on those streets.
SR 520 construction will require the relocation of some sewer lines and other utility lines along the SR 520 and I-5 corridor, including in the Montlake area. WSDOT and the contractor will notify potentially affected residents of work that may result in service interruptions or closures. One notable project is the replacement of a 54-inch-diameter city water line that runs under SR 520 just east of Montlake Boulevard.
Some trees and vegetation will be removed from the project areas near SR 520 due to a number of activities, including building permanent project features and preparing staging areas for construction activities. WSDOT has developed both a Montlake Project Tree and Vegetation Management and Protection Plan (PDF 4.8MB) and an SR 520/I-5 Connection project Tree and Vegetation Management and Protection Plan (PDF 3.7MB). The plans identify specifics areas where trees may be removed or disturbed. WSDOT will also prepare a Temporary Erosion and Sediment Control Plan for both projects to reduce water quality effects from construction
The Temporary Erosion and Sediment Control plans will include the following practices to reduce impacts on soil and vegetation in the project area:
Construction of a new eastbound bridge (the West Approach Bridge South) will require an extensive amount of in- and over-water work. Temporary work bridges and barges are used to complete removal of the old bridge and install the drilled shaft foundations, bridge columns and bridge deck in and over Lake Washington.
WSDOT and the contractor will adhere to all WSDOT, federal, local, and statewide permits and approvals, including, but not limited to:
In addition to requirements of the permits listed above, the design-builder will prepare a Water Quality Monitoring and Protection Plan which outlines a number of best management practices, including:
To receive updates about boating activities and navigation restrictions on Lake Washington, email us at SR520Bridge@wsdot.wa.gov and ask to be added to the boater-notification list. Notification emails will be on an as-needed basis.
To stay safe around over-water work trestles, barge-mounted cranes and other heavy equipment, boaters, canoeists and kayakers should stay at least 100 feet away from all in-water construction equipment and structures.
This map shows the off-limits areas for watercraft during construction of the SR 520 Montlake Project.
During Montlake Project construction, one navigation channel under the SR 520 bridge may be blocked periodically for critical construction work. During these blockages, marine vessels should plan to navigate through the unaffected channel (see below for navigational height restrictions). At least one branch of the navigation channel at the west end of the floating bridge will always be open and accessible to boaters. The navigation channel at the east end of the floating bridge will not be affected by the Montlake Project.
The locations and clearance heights of the SR 520 floating bridge navigation channels.
The contractor will stage equipment and materials both on land and on barges near the construction areas. Staging areas will vary in size and function but will be available for use by the contractor 24 hours per day, 7 days per week. In order to build the new eastbound bridge, the Montlake Project contractor is building a temporary work bridge. The "WSDOT Peninsula," next to the Washington Park Arboretum, is the primary staging area during Montlake project construction, though other staging areas also are used. There will be additional staging locations under and near I-5 for the SR 520/I-5 Connection project (see maps below).
The contractor will use I-5, SR 520 and city arterials as haul routes for construction vehicles during SR 520 construction (see maps below).
SR 520 project contractors will work to limit the community effects of hauling and staging construction materials with actions such as:
Our community construction management plans (CCMPs) outline how the public can provide ongoing input into construction decisions that help to avoid, reduce or mitigate the effects of construction activities on historic properties and other neighborhood residences and businesses. The plans also guide the actions of our hired construction contractors, describe best management practices they are to follow, and provide opportunities for WSDOT to keep the public informed and gather input that improves our construction practices.
Click on the links below to read key SR 520 construction management plans and agreements: