I-5 - Slater Road Interchange - Improvements

Project news

  • The I-5 Slater Road interchange improvement survey is now closed. Thank you for your feedback. WSDOT will share responses and project design options based on those responses during a spring 2020 open house. Due to COVID-19, we are working on a virtual option to present that information.
  • WSDOT will advertise this Connecting Washington project for contractor bidding in October 2022.
  • For information on this, and other Whatcom County highway projects, subscribe to weekly email updates.

Needs & benefits

WSDOT is starting work on a project to improve the Slater Road corridor north of Bellingham, between Rural Avenue, west of I-5, and Northwest Drive, east of I-5.

Traffic studies show the Interstate 5/Slater Road exit (#260) and surrounding interchange will experience more traffic due to rapid growth in the area within the next decade.

In 2014, WSDOT built compact roundabouts to better manage congestion and improve safety on this corridor. Those interim roundabouts have successfully and safely kept traffic moving but they are due for an upgrade.

Using practical design principles, WSDOT engineers will work with people who use this corridor to understand the traffic problems they experience. Based on that feedback, WSDOT will create multiple design options. WSDOT will then work with community residents and area partners to narrow down those designs to a preferred alternative that improves identified problems and stays within the project’s Connecting Washington budget.


Winter/Spring 2020: Work with the community to identify the problems through the corridor.

Summer 2021: Present design options to the community.

Fall 2021: Identify the preferred alternative that addresses the identified problems, while staying within budget.

Fall 2022: Advertise project for competitive contractor bidding.

Spring 2023: Construction begins.

Fall 2024: Construction complete. 


The total estimated project cost is $21.1 million. The funding will come from the Connecting Washington transportation package.


RB McKeon

Melissa Ambler
Project Engineer

A small map of a project area on I-5 and Slater Road in Whatcom County.
A map of the I-5 and Slater Road project area, north of Bellingham, in Whatcom County.

A small photo of the northbound I-5 Slater Road intersection looking east.
The northbound I-5 Slater Road intersection looking east.