I-5 - NB Marine View Drive to SR 529 Corridor and Interchange (I/C) Improvements

Project news

  • This project will improve the interchange at I-5 and SR 529 and extend the existing northbound HOV lane from Everett to Marysville.
  • This project will be advertised in June 2021. 
  • WSDOT is overseeing a process to select a project design-builder. Refer to the Contractor Resources for the latest information.

Needs & benefits

The population of Snohomish County increased by over 400,000 residents between 1980 and 2018. It's expected to gain another 200,000 residents by 2035. This explosive growth increased the number of vehicles using I-5 between Everett and Marysville, with around 65,000 vehicles traveling in the northbound direction alone each day. Drivers frequently experience heavy congestion and long commute times. In addition, traffic at the I-5/SR 528 interchange in Marysville often backs up, creating additional delays.

The 2015 Connecting Washington transportation package provided funding for:

  • A northbound peak-use shoulder lane between Marine View Drive in Everett and SR 528 in Marysville.
  • A northbound ramp from I-5 to SR 529.
  • A ramp from SR 529 to southbound I-5.

WSDOT formed a Stakeholder Advisory Group (SAG) made up of representatives from area cities, agencies, and tribes to make recommendations on how to reduce congestion. In August 2019, with feedback from the SAG, WSDOT selected a preferred alternative. WSDOT will build a permanent fourth lane for HOVs, extending the existing HOV lane in Everett to SR 529. The three general-purpose lanes will remain in place. WSDOT chose this alternative after studying data that shows a high percentage of HOV-eligible vehicles regularly travel through the area.  In addition, WSDOT is looking into how the improved interchange can serve people who bike and walk on SR 529 between Marysville and Everett.

The benefits of a new HOV lane and an improved interchange include:

  • Improved access: A completed SR 529 interchange, with new connections between Marysville and I-5.
  • Congestion relief: A new HOV lane on northbound I-5 will reduce backups and improve traffic flow from Everett to Marysville on both weekdays and weekends.
  • HOV lane compatibility and cost: A new HOV lane is compatible with the existing HOV system between Tacoma and Everett and requires the lowest capital and operating costs. 
  • Bikes and pedestrians: Bike and pedestrian access maintained on SR 529.
  • Restore fish habitat: To mitigate this project, WSDOT will restore about 12.5 acres of saltwater marsh habitat.


  • 2015: The Washington State Legislature approves funding in the Connecting Washington transportation package.
  • 2017- 2020: Project design.
  • 2021: Advertise project.
  • 2022: Begin construction.
  • 2024: Tentative: Construction complete.


Kris Olsen
WSDOT Communications

A small map that shows the primary project area for peak use shoulder lanes between Everett and Marysville and an improved interchange at I-5 and SR 529 in Marysville.

The recommended new design of northbound I-5 from Marine View Drive to SR 529 includes a fixed fourth HOV lane to provide new capacity for transit and carpools.
The preferred alternative includes a fixed fourth lane for HOVs. Visit the blog for details.