Muni officials: Despite ‘rare’ glitch, buses are safe


Despite a computer glitch that led a Muni 3-Jackson trolley bus to crash into a parked vehicle late Monday morning, transit officials say the trolley buses are safe.

Initial reports said Monday’s crash, which occurred near Jackson and Scott streets, was caused by failing brakes. However, a memo obtained by The San Francisco Examiner states the incident was actually caused by a malfunctioning computer system on the bus that was unable to communicate with the brakes.

John Haley, director of transit for the San Francisco Municipal Transportation Agency, wrote in the memo to Mayor Ed Lee and the directors of the SFMTA board that when the operator applied the foot break, it should have sent a signal to the traction motor to decelerate, but it did not.

Haley continued to cite in the memo that when the operator activated the parking brake valve, it should have also activated the same traction motor to reduce power, but that did not happen either.

SFMTA spokesman Paul Rose said the electronic issue with the computer system onboard the 3-Jackson trolley bus was “rare” and that it had never happened before. He said it was:

“An issue so rare that it has never occurred on Muni in 110 million operating miles. We were able to identify the issue and determined it was isolated to the specific bus in question.”

Rose said the 40-foot trolley buses made by Electric Transit Inc., which has gone out of business, do have breakdown issues, but that the buses do not pose a safety issue on city streets. He said every vehicle goes through routine maintenance and checked every morning to make sure the vehicle is safe to operate for service:

“We only put vehicles on the street that are safe and meet all state requirements for Muni service.”

Another issue mentioned in the Examiner story are buses that enter “restrictive mode,” which Rose said is a diagnostic tool that notifies the operator when there’s an issue with the trolley.

One Muni operator who spoke to the Examiner under anonymity said it’s not uncommon to lose steering and the ability to break while in restrictive mode. According to the operator, this has happened at least 10 times and is a “danger for you and your passengers.”

Other operators reiterated the same story, reported the Examiner. Brake failures are another problem operators said they experience on the trolley buses.

However, Rose said if a trolley bus has battery power, steering should continue to work. He countered that the bus does not lose the brakes in restrictive mode, which transit officials confirmed with SFMTA mechanics Friday morning.

The transit agency looked at recent incidents involving restrictive mode and found that none of them involved a collision or put passengers at risk, said Rose.

Officials at the transit agency are working to replace its entire fleet of buses, including all 273 trolley coaches made by Electric Transit Inc. According to Rose, SFMTA plans to start ordering them in December:

“The bottom line here is we do need new trolleys and that is why they are on their way. We need them to improve reliability, not because the current trolleys aren’t safe to operate.”

All of Muni’s new buses that have come into The City in the last couple of years are made by New Flyer of America Inc.

The buses will take some time to get here as a contract needs approval from the SFMTA Board of Directors, the San Francisco Board of Supervisors and Mayor Ed Lee. There is also additional time needed to manufacture and test the vehicles before the buses hit the streets.

Jerold Chinn
Jerold Chinn is the San Francisco Bureau Chief of SFBay. A San Francisco native, he has spent a decade covering transportation in San Francisco. Send tips to or at Twitter @Jerold_Chinn.

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