Lawmakers approved the funding despite complaints that it lacks a definitive revenue source to repay the bonds at a cost of about $28 million a year for three decades. Proponents say they'll use a federal highway fund windfall to cover the cost in the first three years and may seek a dedicated revenue source - like a hike in gas taxes or vehicle fees - as part of a large transportation package in 2015.
The House's 45-11 vote sends the measure to the Senate. Democratic Gov. John Kitzhaber is a strong supporter of the project and his spokesman, Tim Raphael, said the governor would sign the bill.
Oregon will be able to sell bonds only if Washington state comes up with its own $450 million share, the federal government puts up more than $1 billion and the U.S. Coast Guard issues a permit.
The $3.4 billion project would include two new bridges for vehicles, pedestrians, bicyclists and light rail trains, along with new freeway interchanges on both sides of the river. Project designs call for two double-decker bridges with 10 highway travel lanes in each direction, up from six. Portland's MAX light-rail trains would be extended to downtown Vancouver.
The existing bridges are a chokepoint for traffic on I-5 and are vulnerable to damage in a major earthquake. The project has strong support from business groups that hope to speed the flow of freight into and out of ports in Portland and the Puget Sound and from unions looking forward to new construction jobs.
Vocal critics include light rail opponents, neighborhood activists concerned about traffic and pollution, and anti-tax advocates who question the need for the project and its funding. Residents of some North and Northeast Portland neighborhoods fear the project will just move congestion to another I-5 choke point at the Rose Quarter near downtown. Residents of neighborhoods farther east fear tolls on the new bridges will divert traffic to Interstate 205, the only other Columbia River crossing point in metro Portland.
Light rail has been a particularly contentious flashpoint. The budget relies on federal transit funding, and the Obama administration is interested in the project in part because it includes multiple modes of transportation. But light rail critics say it's far too expensive.
Vancouver voters in November rejected a new sales tax to help pay for the light rail extension.