BOSTON — The City of Boston is launching a program to allow free service on three bus routes for the next two years, Boston Mayor Michelle Wu said Wednesday.

Starting March 1, service on Routes 23, 28, and 29 will be fare-free for all riders through Feb. 29, 2024.

Transfers to and from other routes are not included in this program. Riders will need to pay a regular fare if they transfer to another bus or subway line.

These bus routes travel through Roxbury and Dorchester, connecting riders to four stations, Ruggles, Jackson Square, Mattapan, and Ashmont.

By launching this service, Wu has taken the first steps to expand former Mayor Kim Janey's fare free pilot program, after requesting and receiving an $8 million relief fund from the federal government for the city to reimburse the MBTA for the fares.

Each route serves a diverse ridership, and they all intersect with Blue Hill Avenue, which research and advocacy group Livable Streets Alliance identified as a corridor that should be prioritized for reliability improvements and increased ridership, the city said.

This decision is an expansion of the six-month fare-free pilot for Route 28 that was set to end on February 28, 2022.

That bus line has since become the city's most popular, officials said — its ridership surged to 92 percent of pre-pandemic levels, despite overall bus and subway ridership being only at 53 percent of pre-pandemic levels.

"Expanding fare-free transit to Routes 23, 28, 29 will better connect our communities, increase ridership, and ease congestion for all our residents," Wu said. "As we work to ensure every resident knows about the program, we hope this is just the beginning of access to fare-free public transit in Boston."

The three routes are some of the routes with the highest ridership throughout the city of Boston.