The union, however, says the 20-year veteran was justified.
Captured on video, the incident unfolded aboard a B-35 bus in Brooklyn: A woman refused to put out her cigarette, despite other passengers' complaints. Next the buses driver gave her a final warning, and then he literally tossed her off.
Union officials say he had to throw her off for smoking. But once off the bus, it appeared the driver took a swipe at the woman.
The chairman for bus operators in Brooklyn disagrees, saying the driver was just trying to get the woman off him.
The MTA has already publicly disagreed with the union's position. The agency calls the driver's actions "inappropriate" and says he should have called police before using force.
The union says one reason they are defending the use of force is because many city buses are powered by compressed gas. So the union says when someone lights a cigarette there is a threat to the public, and the driver has the right to physically remove that person.
The union says this is a safety issue and a reason why the drivers need better protection.