Mayor Michelle Wu has directed city workers to remove a bus lane that runs along Boylston Street. But transit advocates are asking her to reverse course, saying the lane has sped up bus service for thousands of daily riders.

The dedicated bus lane was first created in 2022 during a monthlong shutdown of the MBTA’s Orange Line. Last summer, the city announced plans to make the lane permanent, citing improvements to bus travel times.

But last month, less than a year after launching the permanent lane, the mayor reversed her decision amid pushback from people who live and work in the Back Bay. In a letter to Back Bay leaders, Wu said city officials found the lane “has not functioned as intended to justify the space allocation,” citing reports that buses often lack a clear path of travel because of cars parking and driving in the lane in order to access local businesses.

“We have heard from community members that this needs to be changed,” Wu said in a February interview with GBH’s Boston Public Radio.

Katie Calandriello, interim executive director of the transit advocacy non-profit Transit Matters, said the mayor’s approach is short-sighted and will hurt 20,000 daily bus riders.

“The decision is definitely influenced by a strong vocal minority,” she said. “It’s important to remember who is really being affected. A lot of these riders are transit dependent and/or low income. And the process that led up to this decision was talking to Back Bay residents and leaders.”

According to MBTA data obtained by TransitMatters through a public records request, the bus lane has performed well in the mornings, especially between Dartmouth and Berkeley Street, with bus travel times dropping 40% during the morning commute.

“We would lose all of those amazing benefits,” Calandriello said.

Calandriello acknowledged that travel times weren’t as fast at other times of day — especially in afternoon commutes and the evenings — and acknowledged that’s because of parking cars, as Wu said in her letter to Back Bay leaders. But Calandriello believes the better approach would be more traffic enforcement rather than dismantling the bus lane altogether.

The mayor’s office did not immediately respond to a request for comment.

City Councilor Ed Flynn, whose district includes parts of Boylston Street and has vocally opposed the bus lane, praised Wu’s move to dismantle it.

“It is critical that we abandon a one-size fits all approach that includes a bus and/or bike lane on all major commercial corridors, instead of working through a genuine community process that considers alternative routes,” he said in a statement.

Wu’s plan comes as the city launches a “ 30-day review ” of changes to all street infrastructure implemented in the past three years, first reported on by StreetsblogMASS. Among the projects under scrutiny are new bike lanes on Berkeley and Arlington streets in the Back Bay, a protected bike lane on Boylston Street and neighborhood speed humps installed citywide.

Wu is facing a mayoral challenge from Josh Kraft, who has criticized the mayor’s transportation policy, especially the installation of new bike and bus lanes.

TransitMatters’ Callendriello said she’s concerned the review process could put other projects that have helped improve travel times and access for transit users around Boston at risk of being dismantled.

“The city has made such incredible progress over the past three years,” she said. “I hope that this 30-day review process is reconsidered.”