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SR 520 - West Approach Bridge North Project Design

What will I see when traveling across the west approach bridge?

Some new features that SR 520 users will notice when driving, cycling, or walking across the west approach bridge include:

  • Wider lanes and shoulders
  • Four-foot noise reduction barriers
  • 14-foot regional shared-use path on the north side of the bridge
  • New Foster Island undercrossing
  • "Belvederes," or viewpoints, along the shared-use path

Visualization of the West Approach Bridge North showing three travel westbound lanes
When WABN opens to traffic, buses and carpools will be able to use a dedicated transit/HOV lane between the Eastside and Montlake interchange.

Visualization of the West Approach Bridge North showing the bicycle/pedestrian path
Bicyclists and pedestrians enjoy the 14-foot-wide shared-use path.

Visualization of the West Approach Bridge North showing the westbound off-ramp
Updated highway interchanges facilitate traffic exiting the highway.

Visualization of the West Approach Bridge North showing belvederes
The shared-use path includes belvederes, or scene viewpoints, to provide rest opportunities for bicyclists and pedestrians.


Rendering of the West Approach Bridge from Lake Washington

The below rendering shows typical sections of the final west approach bridge, including both the funded north and unfunded south bridges.

Visualization of the West Approach Bridge North


What will the Montlake area look like when the West Approach Bridge North is built?

The West Approach Bridge North project includes design features that enhance the Montlake area and minimize impacts during and after construction.

Key design features in the Montlake area include:

  • Intersection improvements
  • Improved exits and merges
  • Wider shoulders and lanes
  • Connections to local and regional bicycle/pedestrian routes
  • New parking, constructed wetlands, landscaping, and pedestrian path at East Montlake Park

Below is an engineering plan that provides additional detail on the Montlake section of the WABN project. 

Plan view of the West Approach Bridge North project

Key landmarks:

A. New stormwater treatment facility
B. Relocated Montlake freeway transit stop
C. New 24th Avenue East off-ramp and shared-use path
D. Two westbound lanes to Montlake Boulevard


How did WSDOT develop the bridge’s design, and did the Seattle Community Design Process inform the process?

Our design team has worked closely with the local design community on west approach bridge design through the Seattle Community Design Process (SCDP). At SCDP public sessions in spring and summer 2012, we shared preliminary design renderings with the public and gathered public feedback on design.

In fall 2012 following the SCDP, we collaborated with the Seattle Design Commission to refine the bridge’s design. Through this process, we incorporated techniques to minimize effects, including:

  • Streamlined bridge design with fewer columns
  • Reduced concrete and materials needs
  • Use of pre-cast materials to minimize construction activity on Lake Washington