While under construction, the MAX Orange Line checked every box: it opened on time and came in about $48 million under budget, despite being one of TriMet's most ambitious construction projects to date.

A year into its Portland-Milwaukie service, however, riders aren't showing up as expected.

Forecasts used to help justify federal funding for the project called for 17,000 average weekday trips in 2016. The Orange Line has so far averaged less than 11,000.

TriMet planners say they're still hopeful the $1.4 billion project will live up to projections. It won't report back to the federal government until the end of next year.

"I'm hopeful," said David Unsworth, TriMet's director of project development and permitting. "We're looking to improve."

The ridership miss comes at a weighty time for the region's transit system.

It's the first time in decades that the Portland region doesn't have a major light-rail project largely teed up or under construction. A proposal for light-rail to Tigard faces a vote in that city that could torpedo the whole project. If it moves forward, the entire region will likely vote on a funding measure that includes the MAX expansion.

One thing planners say they didn't see coming: $2 a gallon gasoline. At the time planners were finalizing the projections, gas prices were around $3 a gallon and headed for $4.

"I think gas prices were significant," Unsworth said. "People are motivated by convenience and cost, and people weigh those differently."

And the ridership predictions were based on Metro population and development forecasts that predate the Great Recession, said Craig Beebe, a spokesman for the regional government.

"We had a recession, which sort of put a hiccup in the whole thing," Beebe said. "Land use in the corridor isn't exactly where they thought it would be."

Close-in Portland neighborhoods have seen intense development in recent years, and zoning changes have teed up even more development along the route.

And Milwaukie has seen property values and home sales rise. New development there could push ridership closer to the transit agency's goal.

But Milwaukie has seen virtually no housing construction since work began on the light-rail line, though city officials say they have several projects in the permitting process.

Early returns on light-rail ridership are often disappointing, said transit consultant Jarrett Walker, because the goals of light-rail go beyond serving the existing audience.

"Most light rail lines are designed to encourage denser and more sustainable development in addition to serving people who are there now," Walker said. "Their ridership is almost always disappointing in the short term."

TriMet and Metro expected ridership to grow to 22,800 average weekday trips by 2030.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus