Thousands of riders were left in the dark as Muni’s NextBus arrival predictions were out of order on Sunday from the morning until the early afternoon.
The service was restored at about 1:29 p.m., according to the San Francisco Municipal Transportation Agency, but bus and light-rail riders were left for hours without knowledge of when the next vehicle would arrive.
It is unclear why the outage occurred.
“We don’t yet know the technical details,” said Paul Rose, an SFMTA spokesperson. But, he said, “NextBus was working on it until about 1:30 p.m.” when the service was restored.”
The predictive service is a mix of realtime GPS data from buses and trains, tempered by an algorithm by the company NextBus, which helps Muni riders see when their next bus is coming — usually.
The NextBus that data was “out of order” Sunday is the backbone of a wide array of Android and iOS apps that offer bus predictions, as well as digital signage at bus stops.
“As alerts on Twitter and the NextBus system indicate, the tracking system is out of order, so arrival predictions aren’t accurate,” the SFMTA’s Twitter account wrote in a reply to an irate customer on Sunday morning.
The customer, Twitter user @nvstvsi, tweeted back, “and this happens all the time. I’ve had to wait 50 minutes for a bus that ‘comes every 10 minutes’ several times.”
Some Muni riders thought they could circumvent the problem by using a third-party app, but that was a no-go, according to SFMTA.
“Sorry to say that all third-party apps rely on our system’s data, so those predictions will be guessed based on schedules,” the agency Tweeted to a rider.
It is also unclear if the NextMuni outage is related to another, ongoing outage of Muni NextBus signage across The City due to a network upgrade from ATT&T wireless.