A locking mechanism "failed" on the rear doors of a Port Authority bus from which a female passenger fell Friday, but why that occurred is not yet clear, the transit agency said today.
The bus, on the 22 McCoy route, was taken out of service and inspected.
The agency checked the fleet's approximately 700 buses and did not find "other similar problems," Port Authority said in a statement.
Inspectors did find two bus doorways -- there are two rear doors on buses that come together and are supposed to remain shut while the bus is in motion -- that were not properly aligned "but did not pose the same risk to riders."
"We did find those issues and corrected them," Port Authority spokesman Jim Ritchie said this afternoon. "Now we know that every vehicle is safe on the street."
The accident occurred Downtown about 6 p.m. Friday as the outbound bus turned the corner from Stanwix Street to Fort Duquesne Boulevard.
Mr. Ritchie said the passenger was standing at the top of the steps by the rear doors and fell against them.
"She actually fell into the doorway as the bus was turning, and the doors were able to open," Mr. Ritchie said. "We're not far enough along to say conclusively why it didn't work."
The woman fell into the street and was initially listed in critical condition.
Port Authority has not identified the passenger.
She remains at UPMC Mercy in the intensive care unit, Mr. Ritchie said.
Bus drivers control the front and back doors with a lever. Asked whether the agency had ruled out driver error accounting for the doors opening, Mr. Ritchie said, "We haven't concluded what caused the lock to not work properly. It appears to us that the cause has to do with the mechanism itself and not some outside intervention with the doorway or the lock."
Jonathan D. Silver: firstname.lastname@example.org or 412-263-1962.