PORTLAND &

It could a decade and $4 billion to do it, but a new Interstate 5 bridge over the Columbia River is badly needed to relieve severe congestion and improve the flow of freight and passenger traffic, U.S. Transportation Secretary Mary Peters said Monday.

"Something obviously needs to be done. It is important to get the new bridge built," Peters said during a visit to Portland.

Earlier Monday, a task force of Oregon and Washington state officials who've been studying the issue released new estimates saying a new I-5 bridge over the Columbia River could cost $3.1 billion to $4.2 billion.

The Columbia River Crossing project could replace the existing six-lane bridge with new spans containing five or six lanes in each direction, plus room for either light rail or bus rapid transit.

Peters, while not endorsing a specific bridge design, said doing nothing "is not an option" because of projections showing worsening traffic congestion on the existing bridge that will lengthen people's commute times, hamper freight traffic and cause more accidents.

"We will have to look at a variety of financing and building options to get the new bridge up as soon as possible," she said, adding that federal funding likely would account for 80 percent or more of the cost of the new bridge.