Sub-inspector Ashok Singh Charak (50), posted at PCR Jammu, was hit by a tractor at Kunjwani area in the city, a police spokesman said.
He was taken to government Medical College (GMC) hospital where doctors declared him brought dead.
A case was registered at Gangyal police station in this regard and efforts are on to nab the tractor driver who fled after the accident, he said.
In another incident, a jeep hit a scooter in the R S Pura area of Jammu killing Balwinder Kumar (27) on the spot while injuring pillion rider Deepak Kumar (12).
In the third incident, a sweeper of Jammu Municipality was hit by a mini bus when he was on duty near the Civil Secretariat.
He was admitted to the hospital for treatment, the spokesman said adding the accused driver was apprehended by the police.