Vandals have been accessing the bus's power switch through a panel door on the sides of the hybrid buses running on the 54-Felton, MUNI spokesman Judson True said.
"The safety issue came to our attention and we addressed it in the short term," True said of pulling the buses.
A long-term solution to the problem may include adding locks to the panel doors, he said. The cost of installing the locks would not be significant, True said.
"Our first priority is making sure that our drivers, customers and vehicles are safe," he added.
Bus service has not been interrupted and is running regularly. However, officials said Wednesday that the agency is working on an increased police presence, which will include undercover officers on buses, on the on the 44-O'Shaughnessy and 54-Felton lines running through the Bayview-Hunters Point District due to a jump in violence on the lines.
The decision was made by Municipal Transportation Authority Executive Director Nathaniel Ford in conjunction with the Police Department, according to True.
There have been 10 reported incidents of violence this year, which have varied from operators being assaulted to vehicles being damaged by thrown rocks, True said.
"We have seen an increase in these sorts of attacks over the last two months and we wanted to let all of our stakeholders know we are doing everything we can to keep customers and operators safe," True said.
Service was temporarily suspended on the 44-O'Shaughnessy and 54-Felton lines earlier in the year due to reported incidents, according to True. He said that service is suspended on a case-by-case basis.
