The MBTA has cut its overtime in half, saving $10 million in overtime costs in the first three months of the year alone, while reducing the number of dropped bus trips to just under 6,000 in the same period, according to T officials who say their crackdown on sick leave abuse is working.

That’s down from more than $20 million on overtime costs racked up during the first three months of 2015, and down from the more than 13,000 missed bus trips in the that time frame.

The plummet in overtime spending and sick leave use comes after the T has stepped up its enforcement of absences, invoking rules already on the books that paid days off run concurrently with sick time taken under the Family Medical Leave Act.

T bosses have been trying to curb overtime spending and sick leave abuse since a Herald investigation last year found rampant sick leave abuse at the T, with more than half of MBTA workers failing to show for work during the heaviest blizzards. The Herald also found worker absences caused most of the nearly 40,000 missed bus trips in 2014.

MBTA workers took 30,300 sick days or unplanned absences in the first three months of this year. That’s 10,000 days fewer than the same time last year, according to MBTA Chief Administrator Brian Shortsleeve.

“Picking up 10,000 days in a quarter is a really big deal,” Shortsleeve said. “It saves millions of dollars in overtime. We owe it to our riders, frankly, to do everything we can to get our drivers to come to work because it has a direct impact on our riders.”

An MBTA watchdog said the results show the agency is getting the message.

“Those are pretty dramatic results and if they continue on that trend that’s very much a positive for the state and the riders,” said Mary Connaughton of the Pioneer Institute, who has raised the alarm about T workers padding their pensions with hundreds of thousands of unused paid sick days under union rules — while taking unpaid family leave days. “Enforcing this policy is not just going to impact today’s operating costs but tomorrow’s pension costs.”

The decline in unscheduled sick leave also contributed to the reduction in missed bus trips with the T reporting 7,203 fewer missed bus trips in the first quarter than the same period last year. The MBTA reported 13,191 lost bus trips in the first three months of 2015, but 5,988 missed trips during for that same time frame this year.

MBTA officials were also forced to admit earlier this year that nearly half of the $75 million spent on overtime in 2015 was paid out to T workers who didn’t even clock in for a full 40-hour work week.