Two disconcerting trends — an increase in unexplained absences by transit operators and a decrease in on-time performance rates — were part of Muni’s latest performance reports.

Muni’s vehicles only registered a 71.1 percent on-time performance mark during the second quarter of this fiscal year, a period that lased from October to December 2010. That mark was a .9 percent drop from the previous fiscal quarter, and marked the lowest performance of the past five recording periods. The agency has a voter-approved mandate to achieve an 85 percent on-time performance rate, a mark that Muni has never remotely approached.

Compounding its reliability woes, the agency recorded a 13.7 percent unexplained absence rate for its transit operators. That mark was a 1 percent increase from last quarter, and the highest rate since the third quarter of the 2010 fiscal year. The agency has a 10.5 percent goal for its operators’ unexplained absences, which include sick days, jury duty, suspensions, and other factors.

wreisman@sfexaminer.com