The union that represents most Metropolitan Transportation Authority bus drivers is telling its members to be extra careful after two drivers were charged in two separate crashes. NY1's Jose Martinez filed the following report.

The snow wasn't the only reason why many MTA buses ran late Tuesday morning. 

The Transport Workers Union advised all drivers to stage a slowdown to protest the arrest of two colleagues on traffic charges.

The job action did not go over well with many commuters.

"The buses were really late, not running real good. And it's worse now," said one commuter.

The slowdown followed Friday's arrest of a veteran driver who was accused of failing to yield after striking a teenage girl in a crosswalk, and the arrest of another driver who fatally struck a Brooklyn man in December.

"We try to do the best that we can with dealing with the situation, as far as dealing with the customers, the pedestrians, the bicyclists, the skateboards, everyone that travels along in our path," said bus driver Ashiya Mack.

The drivers said they are being unfairly singled out under Mayor Bill de Blasio's "Vison Zero" campaign to eliminate pedestrian deaths.

The union's president sent a letter to drivers, telling them to be extra cautious, even if it slows them down.

"If traffic backs up as you await the ability to make an unquestionably 'safe' left turn, so be it. If the bosses are displeased, so be it," TWU President John Samuelsen says in the letter.

"The law is falling on the shoulders of the bus operators. Therefore, bus operators have to be extra vigilant," said TWU Local 100 Vice President J.P. Patafio.

Critics attacked bus drivers on Twitter, and the union fired back, calling its critics "self-righteous brownstoners" and "elitists."

It's not the first time de Blasio and his administration's policies have come under attack from a union. In December, he was criticized heavily by police unions after two officers were shot to death in Brooklyn. That led to a slowdown in police issuing summonses. 

Now, the union is slowing down a bus network that moves more than 2 million riders daily.

"Then, everybody is going to be late to work," said one commuter.

Late to work, even without the snow.