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The long process to replace the Interstate Bridge, between Portland and Vancouver, Washington, remains in the environmental review phase. The evaluation of project components will help inform design.

Right now, the Interstate Bridge Replacement (IBR) program team is building upon work that was completed during the 10-year Columbia River Crossing program, while accounting for changes since it ended, IBR Program Administrator Greg Johnson said. The Modified Locally Preferred Alternative, approved in July by the Executive Steering Committee and the Bi-state Legislative Committee, is the version of the project being evaluated.

WSP USA is leading a general engineering consulting team, and Parametrix is a close partner. Transportation department staffers in both Oregon and Washington are overseeing design efforts.

The project cost is estimated to be between $3.2 billion and $4.8 billion, depending on final design. Cost estimates and potential funding sources will be updated as parties continue to identify and analyze river crossing and transit options.

The National Environmental Policy Act phase is expected to finish by summer 2024, Johnson said, when design should be around 30 percent completed. Construction could start by late 2025 or early 2026 and require eight to 10 years.

Though reduction of traffic congestion is one of the main drivers for construction of a new bridge, another is improvement of safety.

鈥淥ne of the (two spans) that carries I-5 is 105 years old and the other is 64 years old,鈥� Johnson said. 鈥淚f we have a large earthquake, we don鈥檛 know if this bridge would stand up.鈥�

In addition to being seismically deficient, the two spans are 鈥渇unctionally obsolete,鈥� he said, with narrow pedestrian and bicyclist pathways and no shoulders.

A multimodal bridge is planned so that people can cross in a motor vehicle or transit vehicle, on a bicycle, or on foot. The IBR team is looking to integrate bridge transit with existing systems to make sure as many people as possible can be transported through the corridor in a timely manner.

Multiple design concepts are being developed, but one shows light rail running underneath traffic lanes. Those tracks would run alongside Interstate 5 from Portland and up to Evergreen Boulevard in Vancouver.

Tolling has been an integral part of financing for many projects of similar size. As of now, the IBR team is proposing tolling, though any such plan would require approval of transportation commissions in both states.

鈥淭olling was actually a part of the original bridge that crossed the river way back when,鈥� Johnson said.

The Oregon Department of Transportation is looking at tolling options for a new bridge, and Johnson said the IBR team believes such a system would have limited impact on traffic flow in either Portland or Vancouver.

Another challenge before the IBR team is the requirement to secure a permit from the U.S. Coast Guard. Right now, the IBR team is proposing 116 feet between the water level and the bottom of the bridge. After conducting a river user survey, the team believes 116 feet of clearance will accommodate more than 99 percent of river traffic. However, occasionally as much as 178 feet of clearance has been needed by river users.

鈥淲e believe we can mitigate for those users, so we are in a conversation with the Coast Guard, showing them and telling them what we can do to make sure that river traffic today, and in the future, can be accommodated with a 116-foot bridge,鈥� Johnson said.

The final Coast Guard permit could be secured sometime in 2025 or 2026.