BOSTON — The Boston-area transit system is turning to ride-hailing services Uber and Lyft to help provide transportation to disabled customers, officials announced Friday.

The pilot program is designed to supplement and defray the costs of The Ride, the Massachusetts Bay Transportation Authority’s door-to-door paratransit service.

Using a smartphone, registered users of The Ride can hail an Uber or Lyft driver and pay the first $2 of the trip. The MBTA would pick up the next $13 of the trip with the passenger paying any remaining costs.

Paratransit for the disabled and elderly people who can no longer use conventional transit is required under the Americans with Disabilities Act but has proven costly to U.S. transit systems — more than $5 billion per year according to the most recent data from the American Public Transportation Association.

The average cost of operating a single paratransit trip is about $23 in the U.S., compared with less than $4 for the average trip on bus or light rail. The MBTA has estimated the average cost of providing a single trip on The Ride to be as high as $45, while most passengers pay a $3.15 fare. Chicago and Washington, D.C., are among other cities that have explored paratransit agreements with ride-hailing apps.

“This initiative represents the MBTA’s efforts to increase accessibility in a more cost-effective and efficient way that also delivers more convenient service for its paratransit customers,” Republican Gov. Charlie Baker said in a statement.

Baker and other officials unveiled the program at the Perkins School for the Blind in Watertown, which helped push for the initiative.

While trips on The Ride must be booked at least 24 hours in advance, rides on Uber and Lyft can be delivered on demand. The MBTA launched a similar program with several taxi operators in January.

While welcoming more paratransit options, some advocates for the disabled have expressed reservations about Uber and Lyft, noting that the companies themselves have faced criticism and even a handful of lawsuits over a lack of accessible vehicles for the disabled.

One concern is that disabled riders who are ambulatory would be able to use the services but those confined to wheelchairs might not, creating a two-tiered and potentially discriminatory system. About 10 percent of people who rely on The Ride use wheelchairs, the MBTA said.

Uber said Friday it would make wheelchair-accessible vehicles available for the MBTA program through its UberACCESS program, while Lyft said it would provide drivers with wheelchair-accessible rental vehicles provided by a non-emergency medical transportation firm.

The companies also agreed to give drivers with special training for serving passengers with accessibility issues, and all drivers will be subject to criminal background checks under a recently-passed state law.

“Thousands of seniors who are no longer able to use fixed route service rely on The Ride for their transportation needs but as costs have escalated it has become important to explore new options to meet those needs,” said Carolyn Villers, head of the Massachusetts Senior Action Council.