An unhinged scooter-rider socked an NYPD traffic agent in the face and threatened him with a knife in the Bronx – all because the agent was walking in the bike lane, police said Thursday.

The irate man rolled up to the 26-year-old traffic cop and confronted him at East Tremont Avenue and the Grand Concourse in Mount Hope around 8:10 a.m. Aug. 30, authorities said. 

He then punched the on-duty agent and pulled out a knife and threatened him, cops said.

The brute then took off on the moped, heading north on the Grand Concourse towards East 177th Street. 

The traffic agent was taken to BronxCare Health System in stable condition, with bruising to his face. 

The suspect was still on the loose Thursday. 

Cops released a surveillance photo of him riding the getaway scooter.

He is described as about 5-foot-10 and 180 pounds, with a medium build and medium complexion. 

He was last seen wearing a red baseball hat, a black T-shirt, gray pants and white sneakers.