In the final quarter of 2017, the MBTA canceled about 2.6 percent of its scheduled bus rides, an average of about 360 trips a day, because of missing drivers. That rate is roughly equal to the huge service lapses during the winter of 2015, when a series of blizzards prompted a vow by Governor Charlie Baker to fix the T.

Frustrated by the decline in bus reliability, the MBTA is reviewing attendance and medical leave policies, and is planning to hire dozens of new drivers.

An uptick in driver absences last year forced the Massachusetts Bay Transportation Authority to cancel several hundred more buses than normal each day, a setback to the agency’s efforts to improve service.


The agency has embarked on a broad effort to improve its bus network, including pushing communities to reserve traffic lanes just for buses, and speeding up boarding. But the spike in dropped trips threatens to negatively affect how riders think of the service.

“It’s just frustrating more than anything,” said Justin Mason, a Malden resident whose regular commute on the 411 route to Revere is occasionally disrupted by no-show buses. “The alternative is a $10 Lyft or Uber and that adds up quick.”

The MBTA runs about 14,000 bus trips a day, providing around 400,000 rides. Its goal is to complete 99.5 percent of its scheduled routes, which would mean a cancellation rate of 0.5 percent, or about 70 trips a day. But with the rise in driver absences, the cancellation rate reached 2.1 percent for all of last year.

T officials said that during 2017, drivers on average took three more unplanned days off compared to the previous year, driven mostly by higher numbers among part-time drivers, who constitute about one-quarter of the workforce. On any given day in 2017, the T had about 100 fewer drivers than the 1,430 it needed to operate all its buses on schedule.


The unexpected absences are a combination of sick days, bereavement, worker’s compensation, and unexcused absences. But the largest chunk of unscheduled time off falls under the Family Medical Leave Act, which allows qualified employees to take up to 12 unpaid weeks a year.

Employees must first have their leave requests certified by the MBTA. But instead of being out for one long chunk of time, nearly all those certifications are for “intermittent leave,” meaning drivers can take off smaller, but multiple blocks of time, making it more difficult to plan substitutions.

The number of drivers on leave “just seems extremely high,” Brian Shortsleeve, a former T general manager and now a member of its oversight board, said at a public meeting Monday.

James O’Brien, president of the Boston Carmen’s Union, which represents T transit workers, blamed the agency, saying that for years managers encouraged drivers to take unpaid medical leave rather than paid sick days. Since some of these absences last several days, O’Brien said, the agency should have time to adjust.

“They should be able to control that,” he said.

Following the systemwide chaos in 2015, the Baker administration pressured the MBTA to cut down on absenteeism. One year later, the governor boasted at a news conference that absence rates and canceled trips had each declined considerably compared with the peak of 2015. In early 2016, the number of canceled trips shrunk to as low as 1.18 percent, by far the lowest during Baker’s tenure.


But the T has seen those gains evaporate. Baker spokesman Brendan Moss said “there is still much left to do” to address the dropped trips, and said the administration would work to overhaul attendance policies while adding drivers.

Meanwhile, some agency officials question whether the target rate of 99.5 percent completion is realistic.

“Is it a reasonable aspiration for the MBTA?” Steve Poftak, the vice chairman of the T’s governing board, wondered during the agency’s public meeting.

By contrast, New York City had a one-year cancellation rate of less than 1 percent, according to its most recent count. The transit authority in Washington, D.C., reported 3 percent of bus trips since Jan. 2 were canceled, though it measures those differently from the T.

In the Seattle area, the King County Metro transit system completed 99.7 percent of its bus trips in 2017, spokesman Jeff Switzer said. The agency runs 2,000 fewer buses a day than the T but has 1,200 more drivers. And most of its cancellations are due to mechanical issues rather than operator absence — in stark contrast to the T, where 85 percent of canceled rides are because of a lack of drivers.

The MBTA is planning to hire 55 drivers during the fiscal year that begins July 1, but O’Brien said the agency needs even more.

In 2016 the MBTA changed its attendance policy, including requiring drivers to notify managers of an absence at least two hours before a shift starts, rather than one hour. The carmen’s union filed a grievance over the change, suggesting that any more modifications could invite more union opposition.


But the MBTA says additional changes are under consideration, though it did not offer details. And it may more closely scrutinize requests for medical leave, such as enlisting independent medical exams “where legally possible,” said deputy general manager Jeff Gonneville. The agency also plans a deeper analysis of those requests to identify underlying causes. The T is installing new scheduling systems that will allow the agency to better plan for absences. It is also considering allowing drivers to vary their assignments, which might make work more enjoyable, and offering financial incentives to employees with good attendance records.

“There’s no silver bullet,” said Jessica Casey, chief of operations policy for the MBTA. “Together all of those pieces will make up some of the difference . . . to close that gap.”

Adam Vaccaro can be reached at adam.vaccaro@globe.com. Follow him on Twitter at @adamtvaccaro.