$10.3 million: Interstate 5 Bridge transit costs halved in new estimates

New estimates indicate the cost of operating and maintaining light rail trains and express buses on the planned Interstate 5 replacement bridge will likely be less than half the $21.8 million annual price tag that shocked local officials in December.

Interstate Bridge Replacement Program administrators shared the new cost projections during C-Tran’s board of directors meeting Tuesday evening. They said the total operations and maintenance costs — shared by Oregon and Washington — will be closer to $10.3 million a year.

The costs reflect 2035 dollars, representing the year the trains and buses are expected to begin service across the new I-5 Bridge.

Fares should cover about 10 percent of the operations and maintenance costs, leaving Washington on the hook for a little more than $4.12 million a year, said Steve Witter, C-Tran’s project director for the new bridge.

Beginning in 2035, Washington would pay $3.85 million for light rail and $275,682 for express bus service in annual operations and maintenance costs, while Oregon would pay $4.7 million for light rail and $446,543 for express bus service per year, according to the bridge replacement program.

“These numbers are well worked over and based on a lot of hard work over the summer,” Witter said.

The cost projections also are based on a new formula that shows a need for fewer trains and express buses.

Instead of running TriMet’s MAX trains across the bridge every 6.7 minutes during peak hours and every 15 minutes during nonpeak hours, the new estimates support operating light rail trains every 15 minutes throughout the day. The new estimates also reduced express bus service during peak hours from every three minutes to every 7.5 minutes.

Paige Schlupp, assistant program manager for the bridge replacement team, said project administrators had been using a ridership projection model that aligns with federal requirements for Federal Transit Administration grants worth between $900,000 and $1.1 million.

Unlike models the bridge replacement team has used in the past, which took the area’s population growth and regional policies into account, the new model — known as the Simplified Trips on Project, or STOPS, model — relies on nationwide data sets that tend to be more conservative in their ridership estimates, Schlupp said.

While the former model projected 21,600 daily light rail riders based on 2045 estimates using pre-pandemic ridership numbers, the STOPS model estimates 4,600 to 5,400 daily light rail riders based on fall 2024 ridership data, Schlupp told C-Tran board members.

Both models call for the project to extend TriMet’s Yellow Line MAX trains 1.9 miles from the Expo Center in North Portland to three new stations — on Hayden Island, along the Vancouver waterfront and at Evergreen Boulevard in downtown Vancouver.

Both models include 1,270 Park & Ride spaces dispersed among five potential locations, Schlupp said.

The models differ when it comes to tolls on the I-5 replacement bridge. The regional model calls for tolls, higher parking costs and transit fares to help subsidize costs. The STOPS model relies on existing parking and transit fare costs with no tolls included in the cost estimates.

The new bridge, now estimated to cost between $5 billion and $7.5 billion, could be impacted by inflation and escalating construction costs, Interstate Bridge Replacement Program Administrator Greg Johnson said.

Vancouver Mayor Anne McEnerny-Ogle has said delaying the bridge replacement could cost nearly $1 million a day.

“We know this number … will be much higher,” Johnson said. “So we will be putting together a finance plan for how we move forward and get this program into construction.”

Project administrators have said construction on the new bridge could start as soon as 2026, if all goes according to plan.

The best way to get ahead of rapidly escalating inflation, Johnson said, “is getting shovels in the ground.”

Kelly Moyer: 360-735-4674; [email protected]