I-90 Two-Way Transit & HOV Operations Stage 3

Project Summary

In early 2015, IMCO began work on this federally funded highway project in Seattle, Washington valued at over $120 Million. The entire I-90 Two-Way Transit and HOV Operations Project was a $220 Million project administered by the Washington State Department of Transportation (WSDOT). The project was funded by WSDOT, Sound Transit, and the Federal Transit Administration. It brought significant improvements to regional mobility, adding HOV lanes and direct-access ramps for transit and HOVs on Mercer Island and the city of Bellevue. A major component of this project was the infrastructure needed to build the Sound Transit East Link Light Rail Extension from Seattle to Mercer Island, Bellevue, and Redmond.

The project was implemented in stages due to timing and availability of funding. The first phase was completed in 2008 and the second phase was completed in 2012. The third and final phase was partially funded by a federal TIGER Grant, the US Department of Transportation’s Investment Generating Economic Recovery grant program.

IMCO was prequalified to bid this project in September 2014, submitted a bid electronically on October 29th, and was the lowest of four bidders. IMCO oversaw construction that prepared the I-90 tunnels for the Sound Transit light rail to pass through them starting in 2020. Work included adding an HOV lane in each direction between Mercer Island and Seattle, and preserving pavement in both directions from I-5 across Lake Washington to Bellevue. The project built an eastbound HOV direct-access exit ramp at Island Crest Way on Mercer Island and upgraded the I-90 tunnels’ fire and life safety systems.

This project included lane closures and weekend closures in both directions throughout the project lifecycle. All closures were planned for in advance and scheduled through WSDOT and local officials to ensure proper notice was given to the traveling public. Construction started at the end of February 2015 with a weekend closure of eastbound I-90 over Lake Washington. The project was completed on June 1st, 2017 in time to start construction on the East Link light rail across the lake.



Seattle, WA



Contract Amount

$120 Million