The Police Service of Northern Ireland constable discovered the device Sunday when he checked under his car, which was parked at his home, the Belfast Telegraph reported. Investigators said if the officer had not been careful, the bomb might have killed or severely injured his wife and two children.
"If that officer had not checked under his car we would have been looking at a murder or multiple murders," Assistant Chief Constable George Hamilton said.
The bomb was believed to have been placed by dissident republicans. Two men, 24 and 34, were arrested Monday in Belfast.
Another bomb was discovered Sunday near the police station in Tandragee, a town of about 3,000 in Armagh.
Two police officers and a guard at a prison have been killed in recent years, allegedly by dissident republicans who have refused to give up the gun.