It happened Aug. 16 around noon on a crowded bus at Broad and Lafayette streets.
Authorities say they responded to reports of a physical altercation between the bus driver and an adult passenger.
The fight started after the rider reportedly spit on the driver.
That bus driver had told passengers to move to the back of the bus before the fight broke out, officials say.
Newark police have reviewed video of the fight, which appears to show the driver choking the passenger while continuing to punch him.
"It's a bus driver trying to help out the community, and you did wrong to a bus driver that's trying to help us out. He's doing his job and he wants to feel safe," said bus passenger Zoey Clarke.
Both men face a charge of aggravated assault.
Eyewitness News reporter Anthony Johnson spoke to NJ Transit riders, who had a lot of different opinions about what happened, and who was right or wrong.
"He spit on him, which is physical but at the same time I think he should have called the police," Newark resident Darrel Armstrong said.
"If someone spit on me, I'm automatically hitting them," Newark resident Donna Defeo said.
The bus driver is now off the job pending an investigation.
New Jersey Transit released a statement that the issue is under investigation, so they cannot comment on specific details.
"We don't condone any form of assault aboard any of our vehicles or within our facilities. We can confirm that our driver was assaulted prior to the altercation. We want to take this opportunity to remind everyone that assaulting a transit employee is a serious offense and can result in a fine, jail time and/or a ban from riding the transit system."
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