Frequently Asked Questions

Replacing the Interstate Bridge with a structure that meets current seismic standards will address critical earthquake vulnerability issues.

Interchange design improvements and the addition of ramp-to-ramp connections, known as auxiliary lanes, can help optimize traffic flow and improve safety. Best practice is to space interchanges at least one mile apart in urban areas. Seven interchanges within the IBR Program area are spaced closer together than what safely allows for vehicles to get up to speed, make lane-changes and exit decisions, and space to change lanes before more vehicles enter the freeway.

Additionally, designs will include a shared-use path for people who walk, bike, or roll across the bridge. Active transportation facilities will improve traveler safety and comfort for all ages and abilities.

IBR Program investments will improve freight mobility through interchange design improvements, integration of ramp-to-ramp connections (auxiliary lanes), extension of light rail across the river, and improved bicycle and pedestrian facilities. Interchange improvements and auxiliary lanes can help freight move through the corridor more safely and efficiently compared to current conditions. Extending light rail across the river and improving active transportation options will provide travelers with more options to get across the river. With fewer cars on the road, additional space to merge safely, and thoughtful design considerations, freight can experience improved travel times and reliability. 

The IBR Program is proposing a replacement bridge that will be built high enough to eliminate the need for bridge lifts. This will improve freight mobility and reliability for all travelers.

Determining the exact height of a replacement bridge requires balancing the needs of surface, river, and air traffic and access to the communities and population centers on either side of the river. Analyses must consider river use, vessel impacts, freight mobility, highway safety and efficiency, transit efficiency, land impacts, air safety, economic impacts, and cost.

In late 2021, the IBR Program submitted a navigation impact report to the U.S. Coast Guard that proposed a minimum fixed vertical clearance of 116 feet as the first step in the permitting process. The U.S. Coast Guard is the permitting agency who ultimately determines bridge height requirements. The IBR Program will continue to work closely with the agency to meet the needs of users and work through next steps in preparation for the permitting process. If any impacts are determined throughout Program development, the IBR Program would begin discussions with those river users about avoiding, minimizing, or mitigating impacts. The IBR Program is continuing to coordinate with the USCG to obtain a preliminary navigation clearance determination that would support a fixed-span bridge. Until that determination is made by the USCG, IBR continues to study both fixed-span and movable-span bridge configurations.

Both a fixed span and movable span bridge are being studied as part of the National Environmental Protection Act (NEPA) process, which requires federally funded projects to assess their benefits and impacts to the developed and natural environments. The Program is pursuing approvals through the U.S. Coast Guard  for a fixed span bridge with a height of 116. This would eliminate the lift span that currently exists on the pair of bridges that opened in 1917 (northbound) and 1968 (southbound). The lift span currently opens an average of 250 times per year depending on river levels, with some years as high as 480 times a year. This causes delays and congestion on both sides of the river and reduces the efficient movement of goods and services within the region and more broadly across the country. The proposed fixed span bridge with 116’ of clearance because it best balances the competing needs of air, land, and water travel while minimizing environmental impacts and constraints.  Interstate 5 is a critical link for west coast transportation, and a fixed span bridge would better serve the various needs of bridge users whether they’re transporting goods across country or heading to work five miles away.

All designs being studied will make a replacement bridge less steep than what exists today. Grades of both the freeway and bike/pedestrian facilities would meet highway safety and design requirements for freight, other vehicles and active transportation users. Based on preliminary designs, we anticipate that the grade on I-5 mainline would be approximately 4%. The steepest mainline grade in the 5-mile corridor now is 4.7% on the existing bridge. All designs being studied will reduce the grade of the bridge in comparison to the existing structure. The Program will consider all users when making decisions including people who walk, bike or roll on the bridge. The grade of the bike and pedestrian facilities will not exceed 4.5% anywhere in the Program area, which is less than the Americans with Disabilities Act requirements of 5% or less.

The IBR Program has secured $2.1 billion of federal funding through the U.S. Department of Transportation Mega grant Program and Federal Highway Administration Bridge Investment Program (BIP). These are highly competitive funds that were awarded specifically for bridge replacement efforts, so they cannot be shifted to other regional priorities. Both states have also committed $1 billion to help meet the needs of travelers in Oregon and Washington. Replacing the 108-year-old Interstate Bridge with a modern, seismically resilient, multimodal corridor is a priority for the region and the nation, as demonstrated by these investments.

Offering multimodal options for travel is a key piece of the Modified LPA and crucial to the future success of this corridor. The inclusion of two types of public transit will help reduce the number of vehicles on road by providing greater trip reliability and level of service for those who have interest and the ability to shift their mode of travel. This may translate to less congestion for roadway users, such as passenger vehicles and freight haulers.

A replacement bridge will carry high-capacity transit across the river in a dedicated guideway. The IBR Program continues to hear that improved travel time, reliability, safety, and ease of use as important considerations when evaluating transit investments. As the region grows and travel increases, travelers will seek more options. The Program is working with C-TRAN, TriMet and federal agency partners to ensure  transit investments and their level of service meet the region’s needs today and in the future. 

Two tunnel design concepts have already been analyzed as river crossing options. The analysis showed that tunnel options would result in multiple challenges with the present conditions in the Program area and do not address the transportation issues identified in the I-5 corridor near the bridge. Tunnel options were removed from consideration because they do not meet the requirements
of the IBR Program.

Analysis of the tunnel options revealed the following challenges:

• Significant out-of-direction travel for drivers, freight, transit users, bicyclists, and pedestrians

• The inability to tie into existing connections such as SR 14, Vancouver City Center, and Hayden Island

• Potential safety concerns for bicyclists and pedestrians

• Significant archeological, cultural, and environmental impacts

• Cost estimates for a tunnel are estimated to be approximately two times higher than cost estimates for a replacement bridge and approaches. This estimate does not include other highway, interchange, or high-capacity transit improvements that would be necessary.

For more information about the suitability of an immersed tube tunnel, view the Tunnel Concept Assessment

The IBR Program is funded using a diverse range of sources – including federal funds, tolling, and state funds from both Oregon and Washington. The projected total cost of the bi-state Interstate Bridge Replacement Program is $5 billion - $7.5 billion, with $6 billion as the most likely number.

• Federal Competitive Grants ($2.1B committed and $1B prospective)
• Existing Oregon and Washington State Funding ($217M committed)
• Washington Funding Contribution ($1B committed)
• Oregon Funding Contribution ($1B committed)
• Toll Funding ($1.1B-$1.6B anticipated)

Tolls will be used to pay for construction, maintenance, and operation of the facility, and to help improve travel reliability within the bridge corridor. Decisions around rate setting, exemptions, and discounts rest with the transportation commissions in Oregon and Washington.

In summer 2022, the IBR Program’s regional partners endorsed a Modified Locally Preferred Alternative (LPA), which identifies the foundational elements that partners agree should move forward for further evaluation. Elements of the Modified LPA include replacing the I-5 bridge with a seismically sound bridge, improvements to seven interchanges, the addition of one auxiliary lane in each direction, the addition of safety shoulders on the bridge, and the extension of light rail from  Portland to  Vancouver. Additional information on the Modified LPA can be found here.

The Modified LPA was analyzed in the Supplemental Environmental Impact Statement published in September 2024. The Program hosted a 60-day public comment period ending Nov. 20. Responses to the public comments received on the Draft SEIS and refinements to design and technical analysis will be documented in the Final SEIS.

Construction of all IBR Program investments is anticipated to last 10-15 years. A replacement bridge will be built west of existing bridge spans and the existing bridge will remain open to travelers until construction of the new bridge is complete. The Final Supplemental Environmental Impact Statement is anticipated to be published, followed by an amended Record of Decision (ROD) in early 2026. The ROD will allow the Program to move into construction, with corridor construction beginning in 2026.

A potential additional crossing over the Columbia River west of I-5 is an important discussion that should be had and considered in a future appropriate setting on both sides of the river. However, advancement of a third bridge does not address the problems on I-5 associated with the Interstate Bridge and therefore does not address the transportation problems associated with the I-5 corridor. The program’s Memo on Screening and Evaluation of Third and Supplemental Bridge Options summarizes how a third or supplemental bridge option was evaluated, the results of that evaluation, and why a third bridge does not warrant further analysis by the IBR program.

Funding committed for the IBR Program must be used on investments that are part of the IBR Program and cannot be used on a new crossing. Construction of a third crossing would be considered an independent project, requiring a separate environmental compliance effort.

The Oregon Department of Transportation and Washington Department of Transportation are jointly leading the IBR Program in collaboration with eight bi-state partner agencies:

• TriMet
• C-TRAN
• Oregon Metro
• SW WA Regional Transportation Council
• City of Portland
• City of Vancouver
• Port of Portland
• Port of Vancouver

Work is shaped by the governors, the bi-state legislative committee, and transportation commissions.