Video of the incident was recorded on Route 440 this week.
As the tire rolled down the highway, it suddenly jumped onto the median. It rolled along the other side and then headed straight for the Rice family's vehicles.
John Rice, an officer in Piscataway, was driving behind his wife Allison and their three young children.
"Initially I thought please don't hit my wife...please don't hit her," John said on Thursday.
The runaway tire first clipped Allison's car before it slammed into her husband's Jeep.
"I thought it was going to come right through my windshield," Allison said.
John didn't have much time to react and Allison initially feared he was dead.
Fortunately, John wasn't seriously hurt in the incident.
The tire appears to have come from a dump truck; the Rice family would like to know which dump truck is responsible for their scary encounter.
New Jersey State Police is investigating.