SR 520/I-5 Express Lanes Connection Project

Aerial view of I-5 and SR 520 construction

The SR 520/I-5 Express Lanes Connection Project will create a dedicated reversible transit and carpool connection between SR 520 and the I-5 Express Lanes, along with a reversible transit/carpool ramp at the I-5/Mercer Street interchange.

Project materials

Community Construction Management Plan

Check out the I-5 Connection Project’s Community Construction Management Plan (CCMP), which describes what neighbors can expect during construction, what construction best practices the contractor will follow, and how the contractor will avoid or reduce construction effects on neighborhood residences and historic properties. The CCMP gets updated throughout the project duration based on construction activities and public feedback.


The I-5 Connection Project’s Tree and Vegetation Management and Protection Plan (TVMPP) describes project-specific management practices to preserve, protect and avoid affecting trees and other vegetation within a project’s construction area. The plan identifies ways to limit effects on vegetation during construction and establishes an implementation plan to ensure best practices are followed.


We are committed to following noise regulations and using best practices to reduce noise generated by our construction. Daytime construction activities follow daytime noise limits set by the city of Seattle. However, some construction activities occur at night due to safety and traffic concerns. The city of Seattle grants a Major Public Project Construction Noise Variance that sets limits for the allowable level of nighttime construction noise. Read the I-5 Connection Project’s MPPCNV application to learn about nighttime noise limits and commitments to learn about nighttime noise limits and commitments.

View the most recent I-5 construction noise monitoring report (updated weekly).


We strive to the keep the public informed about our project construction activities and effects. We do this through regular public meetings, neighborhood FAQs, community events, and digital communications.

Construction photos