The driver turned himself in, and now video of the attack provides crucial evidence.
Police are grilling the owner of the car over at the 43 police precinct.
The traffic agent is recovering at Jacobi Medical Center.
He's listed in stable condition with a fractured skull which investigators say he got because of an argument over a $115 parking ticket.
Police say traffic agent Edgar Saeteros was writing a double-parking summons when an angry Bronx driver viciously beat him up.
First, that irate driver paces behind the agent, throwing his arms up and yelling at him.
The suspect swings to punch him then pushes him against a fence.
In a nearby parking lot you see witnesses stand back and watch.
"It's horrible. If I would have been there I would have done something about it. I think our community needs to do more looking out for each other," said Diana Adour.
The 35-year-old traffic agent is expected to make a full recovery.
Witnesses say the suspect came up from behind, punched him in the head and knocked him to the ground just after 9 a.m. Tuesday morning.
The man took off running down Virginia avenue in Parkchester, leaving the car behind.
Police commissioner Ray Kelly visited Saetoeros, his wife and 11-year-old daughter in the hospital while detectives did an all out search for his attacker.
"We have the registered owner of the vehicle, who as we speak we believe is reporting or turning himself in to the 43 precinct in the Bronx. As a felony, assaulting a traffic agent. Assaults this year are down, close to 50 percent from what they were last year. But somebody out there doing his job, and viciously attacked, just for doing his job," said Kelly.
Commissioner Kelly is referring to a 2008 change in the law making it a felony to assault a traffic agent.
So far there have been 37 assaulted traffic agents this year, compared to 117 last year.
Traffic enforcement agents don't carry weapons.
Edgar Saeteros has been working in parking enforcement for four years.
The driver has not been identified-no charges filed.