The Federal Highway Administration's Interstate Bridge Replacement Program intends to replace the I-5 interstate bridge between Oregon and Washington where it crosses the Columbia River. The purpose of the undertaking is to improve I-5 corridor mobility by addressing present and future travel demand and mobility needs. The proposed action is intended to achieve the following objectives: a) improve travel safety and traffic operations on the I-5 crossing’s bridges and associated interchanges; b) improve connectivity, reliability, travel times, and operations of public transportation modal alternatives; c) improve highway freight mobility and address interstate travel and commerce needs; and d) improve the I-5 river crossing’s structural integrity (seismic stability). Key project elements include replacement of the bridge over the Columbia River; replacement of the North Portland Harbor Bridge; one auxiliary lane southbound and northbound; extension of light rail from Portland to Vancouver with three new stations; partial interchange on Hayden Island; full interchange on Marine Drive; and an access bridge from Hayden Island to Marine Drive.