PITTSBURGH (KDKA/AP) – A union leader is taking issue with the Port Authority’s contention that two bus drivers may have been engaging in reckless behavior before one of them crashed.

The Port Authority says surveillance video appears to show the drivers gesturing at each other moments before one bus crashed through a guide rail and rolled 100 feet down an embankment from Interstate 279 on Monday afternoon.

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Agency spokesman Jim Ritchie said the drivers could be fired if investigators confirm that their “joking” and “reckless” behavior caused the crash.

In an e-mail to the Port Authority Board members, it stops short of saying the two drivers were drag racing.

“They were going fast,” Ritchie said. “They were switching lanes, as I said, they were gesturing to each other at the same time and at some point, the buses did make contact with each other.”

Stephen Palonis, president of Local 85 of the Amalgamated Transit Union, said he saw no reckless driving and thinks the drivers merely waved to each other.

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He said a mechanical issue could be to blame for the crash.

Fortunately, there were no passengers on the bus at the time.

The second driver involved in the accident appears to have stopped briefly after the accident, but then drove away and did not report the accident.

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