A grant-funded program that offers affordable transportation for seniors with medical appointments on Cape Cod may end in October if an alternative funding source cannot be identified, elder advocates said.

The program is currently managed by the Vineyard Transit Authority and is funded through a one-year $50,000 federal seed grant administered by the Massachusetts Department of Transportation (DOT).

The service operates on Wednesdays, picking passengers up at the terminal in Vineyard Haven and bringing them to appointments in places including Sandwich, Falmouth and Yarmouth. Routes vary depending on the need, according to VTA representative Suzanne Cioffi.

The VTA secured the one-year grant for the program last year after a similar program from the Center for Living was discontinued. The VTA manages vehicle insurance, driver dispatch and maintenance of vehicles. The vehicles have a capacity of up to 17 passengers each week, and the service is in regular demand. The rides cost $20 round trip and caregivers can also be accommodated.

“Every week except around Christmas and the beginning of the year we’ve had people,” Ms. Cioffi told the Gazette.

She said the program does not qualify for another DOT grant since the funding was aimed at new programs. An informal working group including representatives from the advocacy group Healthy Aging MV, the senior day facility the Center for Living, Elder Services, Vineyard Village at Home, the VTA and the Martha’s Vineyard Commission has convened to pursue other funding sources and options.

“It’s possible, but finding funding for this is always challenging,” said Center for Living executive director Leslie Clapp. “The VTA has been great and they really did step up and take the bull by the horns, but they were only able to do this pilot program.”

Ms. Clapp said many people who use the service are traveling for specialized ophthalmology appointments including treatment for cataracts. She said others travel off-Island for neurology, radiation therapy and dental services.

“There’s a lot of medical services that are not available on the Island,” she said. “I still get calls from people who tell me, I can’t get an appointment on Wednesday, so it’s not meeting the need, but it’s as good as it can be at this point.”

Paddy Moore of Healthy Aging MV said existing transportation services do not meet the need, especially with a growing elder population on the Island. Funding for the program is set to run out at the end of September.

A separate service that offers rides to Boston will remain unchanged.

“I don’t think anybody’s pushed the emergency button yet, but there’s no question about the need,” Ms. Moore said.