I-5 - 179th St. Interchange - Interchange Improvements

Project news

On Tuesday, Sept. 10, 2019, a public open house was held at Alki Middle School, in partnership with Clark County Public Works, to share interchange design concepts for the I-5 - 179th Street Interchange, in west Clark County. View design concepts

Needs & benefits

This project will improve mobility and safety for travelers who use the I-5 - Northeast 179th Street interchange by making interchange improvements and replacing signalized intersections with yet to be determined interchange design at the on- and off-ramp entrance and exit to and from I-5. Route enhancements through the interchange will also make the area more accessible to bicycles and pedestrians. The project will also look at the feasibility of replacing the I-5 bridges over Northeast 179th Street and fixing nearby fish barriers. 

This is a Connecting Washington project that is being planned, in partnership with Clark County, as one of a series of projects along Northeast 179th Street.  These transportation improvements will support the Clark County Comprehensive Growth Management Plan for the area.  See the Clark County NE 179th St Corridor Improvement project webpage for more information on the projects being planned for by the county and private development.

Originally built in the early 1960's, the Northeast 179th Street Interchange is in need of upgrades and safety improvements to bring the interchange up to today’s design standards. With anticipated growth in Clark County, the existing interchange configuration is not expected to be able to accommodate future traffic volumes.

WSDOT is currently developing the scope of the interchange improvements. The interchange design will not begin until 2023; however, these transportation system improvements will be necessary to support the future growth and development in Clark County. More importantly, this project will improve traffic flow and reduce delays that will occur if nothing is built.   


  • Summer 2023: Interchange design phase begins
  • Summer 2027: Project goes to competitive bidding
  • Fall 2027: Construction anticipated to begin
  • Fall 2030: Construction anticipated to be complete 


This project is part of the 2015 Connecting Washington Investments funding package and the estimated cost of this project is $50 million. Connecting Washington is a 16-year program, funded primarily by an 11.9-cent gas tax increase that was fully phased-in on July 1, 2016.


WSDOT Clark County Engineering Office


Clark County 179th Street Project 


I-5/179th Street - Interchange - Interchange Improvements - project map