Interstate Bridge Replacement Program estimate jumps to about $14.4 billion; staff warn of multi‑billion funding gaps and a critical federal deadline

Carly, interim program administrator for the Interstate Bridge Replacement Program, told the committee that a new cost‑validation process produced a 2026 planning estimate for the five‑mile program of $13.5 billion to $15.2 billion, with a planning figure of $14.4 billion at the 70th percentile.

Carly said the estimate breaks down to a base cost (about $7.8 billion in today’s dollars), program risk ($4.2 billion) and escalation ($2.4 billion). She said construction‑market inflation and a realized two‑year federal environmental review delay are major drivers behind a roughly 58% increase in construction costs since the 2022 estimate.

Program staff described an initial, funded core phase focused on replacing the Columbia River bridges with capacity for light rail and connections to I‑5, Hayden Island and SR‑14. That first core package was estimated at roughly $7.65 billion; staff said a $2.2 billion gap remains to build the full core package as currently scoped, which could fall to about $1.2 billion if an anticipated Federal Transit Administration capital investment grant is secured.

Carly cautioned that federal procedures require updated STIP and MTIP entries and a Record of Decision before certain obligations can be completed. “There’s a half a billion dollars that will expire at the end of September if we are not able to meet that deadline,” she said, urging JPACT and Metro Council to coordinate on schedule and STIP/MTIP updates.

Staff outlined a phased delivery approach and a procurement timeline that includes a mid‑year request for qualifications, a request for proposals by year‑end, contractor selection in 2027 and bridge construction starting in 2028 under a progressive design‑build model. Transit construction tied to a full funding grant agreement would follow (FTA CIG target and construction between 2030 and 2036).

Elected officials pressed staff on toll design and traffic diversion to I‑205, whether tolls would be temporary, and whether a tunnel or using an existing bridge for light rail had been analyzed. Carly said toll policy decisions rest with future policymakers and transportation commissions, noted examples where diversion trends often “level out” over time, and said the program had analyzed tunnel options and found them infeasible because of extensive excavation and connectivity impacts on both riverbanks. She reiterated that the proposed replacement bridges include space for dual light‑rail tracks and shared‑use paths.

Staff said they will continue to pursue federal grants, toll revenue, state contributions and potential efficiency measures to close funding gaps and that they were working with the Treasury offices on tolling scenarios. Next scheduled steps include publication of the final supplemental EIS and a Record of Decision expected mid‑year; procurement milestones and STIP/MTIP updates will follow.