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SR 520 - West Approach Bridge North Project: What's Happening Now?

Updated: Aug. 11, 2017

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Project photos

See more photos of SR 520 construction
on our Flickr site .

Project overview

The West Approach Bridge North (WABN) project is underway in the Montlake area and on Lake Washington. Work hours may vary depending on the construction activity. Construction crews will continue to employ best management practices throughout construction to minimize impacts on the community and environment. Due to the dynamic nature of construction activities, construction plans are subject to change. WSDOT will provide the public with ample notice before construction activities or closures occur.

In the next few weeks, crews will begin the following activities within project boundaries:

Project milestones


Construction activities under a city of Seattle temporary noise variance

  • No activities currently under a city of Seattle noise variance

Construction activities


Opening of new westbound SR 520 HOV and general-purpose lanes

The news: WSDOT is opening the new westbound SR 520 transit/HOV and general-purpose lanes.
The date: 5 a.m. Monday, Aug. 28
The big deal:
Drivers: Westbound drivers will no longer curve left at the end of the floating bridge, instead they'll drive straight onto the new transit/HOV and general -purpose lanes.
Transit riders - Users of the westbound SR 520 transit stop at Montlake Boulevard will have a new location under the 24th Avenue East Bridge and will get there using the same access path to and from Montlake Boulevard.

Map of new westbound SR 520 HOV and general-purpose lanes
Click image for larger, printable version. (pdf 3.85 mb)

SR 520 closures 

Full closure of SR 520 late August 2017
From 11 p.m. Friday, Aug. 25, to 5 a.m. Monday, Aug. 28, crews will close all lanes and ramps of:

  • Westbound SR 520 between 92nd Avenue Northeast and Montlake Boulevard.
  • Eastbound SR 520 between I-5 and 92nd Avenue Northeast.

See more details about the August closure the SR 520 Orange Page.


Arboretum Waterfront Trail closure

The Arboretum Waterfront Trail is now open.

Arb trail is open
Click image for larger, printable version. (pdf 5 mb)  

Construction activities near the MOHAI and Old Canal Reserve staging areas

Activities in the next few weeks

Nighttime work

  • No nighttime work is currently scheduled for the coming week (Aug. 7-11).

Daytime work
Repositioning the East Park Drive temporary fencing: In progress

  • Where: Crews are removing portions of the temporary wooden fence along East Park Drive and replacing it with a chain-link fence in order to complete the ADA parking spots at East Montlake Park. (See parking spot details below.)
  • Impact: The fence line is now aesthetically different.

Installation of new parking spaces on East Park Drive East: Aug. 7 – Aug. 18

  • Where: Crews will install the final bay of parking spaces on East Park Drive East near East Montlake Park.
  • Impact: Nearby neighbors may hear a grader and rollers as crews prepare the site. Crews may need to temporarily close East Park Drive East for one day as they pave the new parking spaces. Paving work is expected to take place the week of Aug. 14. We will provide the specific date of the East Park Drive East paving once it is set.
  • Note: Active use of these new spaces will not begin until after the completion of the Montlake Phase. Trees in planter boxes will occupy the parking spaces until the end of the Montlake Phase. In conjunction with the repositioning of the fence and installing the parking spaces, contractors will begin work in East Montlake Park. Crews will remove asphalt and curbing to construct an access path as well as complete restoration work in the park.

Paving of new westbound lanes: Aug 7 – Aug 23

  • Where: Crews continue to connect the new WABN structure to the existing westbound SR 520 near the 24th Avenue East bridge. This work will continue over the next few weeks and will culminate in opening of the new westbound SR 520 mainline after a weekend closure Aug. 25-28.
  • Impact: Nearby neighbors may feel vibrations as crews compact and grade the embankment in preparation for paving operations. Neighbors may also hear graders, vibratory rollers, milling machines and pavers.

Landscaping in the Old Canal Reserve: Beginning August 26

  • Where: Landscaping will potentially begin over the weekend closure in late August. The work is currently on hold as the current configuration of the 24th Avenue East/Lake Washington Boulevard off-ramp has made access to the Old Canal Reserve area difficult.

General construction reminders

  • Vibrations: As you read above, crews are working in the MOHAI and Old Canal Reserve and you may feel vibrations as a result. Much of this work will take place during daytime hours.
  • Dust: WSDOT continues to monitor dust closely. Flatiron has maintained a pattern of watering down the work site on a nearly-hourly basis.
  • Work hours: During the regular work week, Flatiron continues to have a crewmember stationed at the MOHAI entrance gate ensuring work in this area does not start and deliveries do not occur before 7 a.m. 


Continued bicycle/pedestrian detour on Montlake Boulevard

Since the 24th Avenue overpass closed last fall, bicyclists and pedestrians have been detoured from 24th Avenue to the Montlake Boulevard sidewalk, via East North Street. For your safety, please continue to use the signed detour route along Montlake Boulevard, as shown in the map below. To avoid potential conflicts between bicyclists and pedestrians with construction vehicles and off-ramp drivers, the bicycle-pedestrian path across 24th Avenue East bridge will remain closed during this temporary configuration. For more information on this topic, check out our "Frequently Asked Questions" document.

Stay tuned for updates on bicycle-pedestrian access through this area as the WABN project is completed in 2017. WSDOT secured full funding in 2015 to build the remaining west side portions of SR 520 and is currently evaluating how to phase the remaining portions of the SR 520 Bridge Replacement and HOV Program. There may be additional changes as we identify how the next phase of construction interfaces with the WABN project.

Detour route

Click image for larger, printable version. (pdf 5 mb)

City of Seattle temporary noise variances

When needed, a temporary noise variance can be granted to Flatiron by the city of Seattle to allow the contractor to conduct noisier work outside the typical hours of construction.

  • The city's noise ordinance allows for variances for louder nighttime work between 10 p.m. and 7 a.m. on weekdays and 10 p.m. to 9 a.m. on weekends.
  • Use of noisy impact equipment, like jackhammers, will occur before 5 p.m. as required by the temporary noise variance.
  • WSDOT inspectors will monitor nighttime activities to be sure work complies with city of Seattle requirements.

Watercraft restrictions

For boater information, please visit our SR 520 Boater webpage.


Tree protection and removal

To make way for the temporary bridge and staging areas, crews removed trees as necessary on Foster Island and in the Montlake area. WSDOT worked with the city of Seattle to remove as few trees as possible, and will continue to mark trees for protection with orange fencing and will coordinate on replacement plantings.