I-405 Northbound Peak Use Shoulder Lane Project, SR 527 to I-5

Why is WSDOT building this project?


Northbound I-405 experiences heavy congestion, especially in the Bothell area during the afternoon commute. With funding from I-405 toll revenue, the Washington State Department of Transportation plans to build new capacity between State Route 527 and I-5 to help relieve congestion.

What peak shoulder use looks like

I-405 Peak Shoulder Use Visualization

The end result


The primary focus of this project is building a new northbound peak use shoulder lane, which will add new capacity for general purpose traffic. The new lane will extend for about 1.8 miles between SR 527 and I-5.  

WSDOT will also construct one new noise wall along northbound I-405.

Overhead lane control signs will display whether the peak use shoulder lane is open to traffic. The lane will generally be open to traffic during the peak afternoon commute (3 to 7 p.m.). Vehicles over 10,000 gross vehicle weight will be prohibited from using the lane, with the exception of buses.

Project vicnity

I-405 Peak Shoulder Use Vicinity Map

Project benefits


By building more capacity to handle the large volumes of traffic entering I-405 from SR 527, we expect to improve congestion that travelers are experiencing, especially in the area near the SR 522 interchange, where I-405 has less capacity.

The I-405 project office is evaluating additional longer-term projects to provide benefits in the area between SR 522 and I-5.

What is the project timeline?


Contract awarded: November 2016 to Graham Contracting Ltd.
Construction start: January 2017
Open to traffic: Spring 2017

Learn more on WSDOT's website.
Updated March 23, 2017