35th Ave SE Corridor, Phase II (SR 524 to 180th St SE)

Update, July 2021

35th Ave SE – Phase II construction could result in up to 15-minute delays for commuters at the intersection of 35th Ave SE and 180th St SE near Bothell from 7 a.m. Monday morning Aug. 2 through late Tuesday evening Aug. 3. This temporary traffic revision, which will last overnight, takes each approaching leg down to one lane with just one direction moving through the intersection at a time.
The work will install a new water main under the road. This important utility can only be disconnected for 40 hours to limit impacts to homes in the area. Crews must work around the clock to complete the work in this short time.
Please plan ahead and allow extra time to travel through this area. Use alternate routes when possible.

Project Description

Snohomish County is improving the 35th Ave SE corridor, between SR 524 and 180th St SE, by adding bike lanes, center turn lanes, planter strips, sidewalks, and stormwater detention and treatment facilities. The corridor is an important north-south route for Snohomish County residents in a rapidly developing area of the county. The project will improve traffic flow and help ease congestion during busy morning and afternoon commutes. The addition of continuous center turn lanes will reduce delays caused by turning vehicles.


  • 2016-2020: Design, survey, environmental review, right-of-way acquisition. The process of developing road projects takes several years. Many factors must be considered, including: location of homes; public right-of-way; stormwater runoff, drainage and water quality; wetlands and buffers; hilly terrain; sight distance; soils; traffic volumes; accident history; vehicle and pedestrian access; location of utilities; and information that residents provide about the area.
  • 2021-2022: Construction began in spring 2021.

Environmental Review

An environmental review was completed in compliance with the SEPA. An environmental checklist was prepared on January 4, 2018.

A Determination of Non-significance (DNS) and Notice of Land Disturbing Activity (LDA) Permit were issued on January 17, 2018. They are also available for viewing at Snohomish County Public Works during normal business hours:


As part of the widening project, Snohomish County purchased right-of-way adjacent to the road from property owners along 35th Ave SE. This process began in 2017. More information on the right-of-way acquisition process is included in the Before we Build Pamphlet.

Public Meeting

Snohomish County Public Works held a public meeting on June 27, 2017 to discuss four projects in this area. The projects were the 35th Ave SE - Phase II, 43rd Ave SE/Sunset Rd, 180th St SE Phase I and II, and 196th St SE/Grannis Rd. Staff was available to answer questions, review proposed improvements, and gather feedback on potential designs.


Other Projects in the Area