That means under Muni’s definition, buses are considered "on time" if they arrive at a stop up to 4 minutes, 59 seconds late.
While even that definition is stricter than at some other transit agencies – buses in Washington, D.C., for example, are considered on time as long as seven minutes after the schedule – Muni riders said the manipulation of Muni's numbers is important.
“There are standards that they are supposed to meet, and they are not meeting those standards by cheating,” said John Holtzclaw, who works on transportation issues for the Sierra Club. “The importance of having the on-time percentage is that it puts pressure on the city to make the changes that are necessary for Muni to run faster and more efficiently.”
By using an elongated definition of a minute, the transit agency inflated its on-time performance rate for months.
Muni reported its on-time performance was about 71 percent for the last three months of 2011. But a Bay Citizen analysis – using the traditionally accepted definition of a minute – determined that Muni vehicles were on schedule 61.4 percent of the time. And from July to September 2011, the transit agency’s on-time performance was 59 percent, not the 72 percent it claimed for the period.
With its inflated performance statistics, the transit agency moves closer to meeting an on-time rating of 85 percent, the target set by a 1999 voter-approved initiative.
Muni officials acknowledged that the agency reported many late vehicles as on time.
“We recently identified that the current algorithm rounded down the number of minutes if it were 4 minutes, 25 seconds,” said Muni spokesman Paul Rose.
An SFMTA board subcommittee plans to discuss on-time performance at its meeting today, and the agency expects to update its algorithm to include an additional on-time metric using the strict definition of a minute, Rose said.
The transit agency would not say exactly when it began defining four minutes as 4 minutes, 59 seconds, but the new definition went into use sometime in 2010. Since 1999, Muni’s method for calculating its on-time rates has continually evolved, according to John Haley, the agency’s transit director.
“The measurement, such as it is, is meaningless to the rider,” Haley insisted.
He said the on-time performance rating doesn’t take into account a number of key factors, including the different types of vehicles Muni uses. “We're not standing here saying, ‘Gee, we think 71 percent is a good number,’ ” he said.
Other transit agencies use different definitions of “on time,” while still adhering to the 60-second minute.
“Oh, God,” said Chris Peeples, an Alameda-Contra Costa Transit District board member, when asked how AC Transit defined its window for delivering on-time service, before explaining that the district relies on the standard definition.
“If you go to the dictionary and look up ‘minute,’ it'll say 60 seconds,” he said.
From a transit agency perspective, Peeples said, being early – or “hot” – is considered worse than being late. His agency has a six-minute window for lateness.
The city attorney’s office said it does not plan to investigate how Muni determines its on-time rates. The Metropolitan Transport Commission, the government agency charged with auditing transportation agencies throughout the Bay Area, declined to comment, saying only that it tries to avoid “micromanaging.”
But its 2010 Muni audit did note that “on-time performance and headway adherence were particular areas in which SFMTA fell well short of its standards.”
Gabriel Metcalf, head of the San Francisco Planning and Urban Research Association, which helped draft 1999’s Proposition E that created the SFMTA, said he thought it was probably “a mistake to write performance metrics into the (city’s) charter.” Still, he said Muni should not be padding its on-time records.
“I want accurate information. They shouldn't be playing games with the numbers. They should report honestly,” Metcalf said. “As a city, we've got to do a lot better.”
Using data obtained through a public records request, The Bay Citizen analyzed the entire set of Muni vehicles that were on time, late or early in the last half of 2011. The agency routinely collects on-time samples during various periods each day. Because of this, The Bay Citizen's figures would differ slightly from the agency's, even if it used the dictionary definition of a minute.
The question of what constitutes a Muni minute might be moot by August, when the agency is slated to use a new set of performance factors. The new system will use some different metrics and will categorize lines by vehicle types and ridership levels. One of the most important metrics will be “headway” – that is, the time between two buses arriving at a stop on the same route.
Most Muni riders can expect a bus or train at regular intervals, and the interval will vary according to each line. For instance, the 14 Mission line might come every seven minutes, while the 33 bus might be every 10 minutes. This, said Haley, would be a better way to measure Muni than on-time performance, no matter how you count a minute.
City leaders are looking for better performance and greater transparency from Muni.
“Given the everyday frustration caused by Muni's chronic lateness, this new data isn't a huge surprise, but it is disturbing," said Board of Supervisors President David Chiu, a frequent Muni rider. "I do have some confidence, though, that the new MTA leadership will move quickly to provide more accurate on-time data and to implement the fundamental reforms needed to fix the underlying problems with Muni service."
Zusha Elinson contributed to this report.
