More than 1,600 users of the ride-sharing program Vanpool Hawaii face higher monthly fees to get to and from work.

For 17 years the program was funded by federal money funneled through the state Department of Transportation. But the Federal Highway Administration decided to stop subsidizing the program in April 2010.

Since then the state has spent $3.7 million out of the highway fund to subsidize the program. But the state decided this month to stop the subsidy, and is working with Vanpool officials to identify other sources of federal funding. The program costs about $3.5 million a year to operate.

"Looking forward with the amount of money that’s been spent, the Department of Transportation determined that we could no longer help fund this program," said state transportation spokesman Dan Meisenzahl. "The state just can’t afford to pick up the tab."

VPSI Inc., which does business as Vanpool Hawaii, sent letters of notification to users across the state, including 1,403 on Oahu and 170 in Hawaii County, where the program started. The company runs 323 vehicles.

State funding will end June 30. On Thursday, Vanpool Hawaii will hold an informational meeting for users on the status of the program.

The ride-sharing program allows a group of up to 15 people to rent a van for $65 each per month, or $80 a seat in a sport utility vehicle.

Vicki Harris, the program’s executive director, said she has no idea how much that fee would increase without the subsidy.

"Because of the subsidy from HDOT that has kept that price for years and years, there’s only been three price increases," Harris said, adding that the monthly fee started at $50. "I wish I could tell you what an increase could possibly be. I really don’t know."

However, users will know 30 days in advance what the increases will be.

Meisenzahl said the federal decision to cut funding was an "administrative" one, but could not outline the exact reasons as of press time.

He said federal officials still support the program but did not like the way the money was funneled through. The program received funding from the highway administration and the Federal Transit Administration, but that money would go through the city, then through the Oahu Metropolitan Planning Organization and then back to federal officials.

THE STATE would pay for the program, and the federal government would then reimburse the state, Meisenzahl said. Most van pool programs on the mainland are operated on the county level.

"Now it’s just a situation where we have to figure out how we can route the money and keep the program alive," he said. "We have to see whether it’ll go through the city and county. It’s just a matter of working through the process."

Harris said the company is seeking funding from private companies as well, and will seek sponsorship from fuel companies.

Charlotte Lenseigne, an Aiea resident who works at Tripler Army Medical Center, drives six other Tripler employees to work. She’s used Vanpool for six years and doesn’t own a car.

"They’d be paying for insurance, brakes, gas, everything in general," she said of people who own cars. "One of the girls in our van pool, she’s saved over $3,000."

Lenseigne said the top advantages of the service include cost savings, convenience and less environmental impact. Another benefit is that drivers in the pool get to use the vans on the weekend.

"We’re all hanging tight just to see what happens," she said.