The charter bus driver who crashed in Queens on Monday — killing three people, including himself — should never have been allowed back behind the wheel after drunkenly causing a chain-reaction collision in 2015, a woman hurt in that incident told The Post.

“I’m just shocked he was even allowed to drive a charter bus after that,” said Alexandra Wynne, 24, of East Haven, Conn.

“That’s crazy. This tragedy could have all been prevented if this company took precautions by looking into who they were hiring.”

Wynne said she was stopped at a red light just off I-95 in New Haven on April 10, 2015, when Raymond Mong — then a bus driver for the MTA — came “flying off the highway” behind her.

The 2002 Honda Accord he was driving smashed into the rear of a 2004 Chevy Tahoe, which then slammed into the 2011 Volkswagen Jetta that Wynne was driving, according to police records.

“His car was smoking after that, but he still backed up and then drove off on the highway,” Wynne said.

“I was in shock. I was like, ‘Wow,’ I couldn’t believe he just drove off like that. And he was going fast. Highway cops ended up getting him a short time later.”

Wynne said she suffered a head and back injury, while her boyfriend, who was in the passenger seat, was also hurt. Wynne said she recently settled a suit over the collision.

“I feel bad for these people in Queens,” she said.

“I luckily walked away from my crash. I can’t believe this guy was allowed to get a job driving.”

Mong — who was fired by the MTA following his arrest — pleaded guilty to operating a motor vehicle under the influence of alcohol or drugs, and was sentenced to 18 months’ probation.

In addition to the people killed Monday, 16 others were injured — five critically — when Mong, 49, rammed a Q20 bus in Flushing around 6:20 a.m.

The owner of the bus Mong was driving, Dahlia Group Inc. of Flushing, didn’t return calls for comment.

But the defense lawyer who represented him in the criminal case, Justin Smith, said: “My heart goes out to his family and to the families of all the victims. It’s a terrible tragedy.”