It looked like one driver talking to another but as Senior Constable Peter Bines drove past he realised something was amiss.
Yesterday he was formally recognised with a District Commander's Commendation for dedication to duty at the Rotorua police awards.
Mr Bines was off-duty on October 12. He was in his car with his wife Fiona at the Fenton St Amohau St intersection when he saw what looked like one driver talking to another.
As he drove past he saw one man punching the other, he said.
"I was still moving and I think I just put the truck into neutral and got out while it was still rolling and went into work mode," Mr Bines said.
"When things like this happen you have to do something about it."
Acting Area Commander Inspector Tim Anderson said the man was punching the other driver in the face and gouging at his eyes when Mr Bines stepped in.
"He pulled the offender off and there was a bit of a struggle with Senior Constable Bines bitten on the arm," Mr Anderson said.
"He managed to restrain him until police arrived. The victim had a broken nose, bleeding to his eyes and cuts and bruises to his face but if it wasn't for his actions it would have been a lot more serious. In my view it could have been fatal."
Mr Bines was accompanied by Fiona to the awards. Mr Bines said Fiona played a pivotal role in the incident, helping the victim until emergency services arrived.
"She wanted to intervene in the scrap but I didn't want to get her involved."
He said he knew he had been put forward for the award but did not know he had been accepted to receive the commendation. He also received his 21 years' long service clasp yesterday.
Awards:
Certificate of Appreciation: Margaret Irvine, Janet Gaunt, Betty Griggs, Brita Swears, Val Reid; Diploma in Police Workplace Practice: Constable Luke Miller, Con Tatum Campbell; 2011 Canterbury Earthquake Citation: Sergeant Lehi Hohaia; Certificate of Promotion to Sergeant: Lehi Hohaia, Aaron Bateman; Certificate of Promotion to Senior Sergeant: Zane Smith; Long Service medal 14 years: Sgt Aaron Bateman, Con Mike West; Long Service badge: Lynne Morris; Long Service clasp 21 years: Snr Con Peter Bines, Det Sen Sgt Zane Smith, Sen Sgt Denton Grimes; Long Service clasp 28 years: Sen Con Eric Grace; District Commander's Commendation: Sen Con Peter Bines; Rotorua Police Baton of Appreciation: Dave Dalziell.