Officials say David Gibson of Raritan may have been cut off by another vehicle at the intersection of Church and Broad streets in Flemington on Tuesday.
Prosecutor Anthony Kearns III says Gibson got out of his vehicle at the next intersection and broke the window of the other vehicle. Authorities say the 53-year-old then stabbed the other motorist when he got out of his vehicle.
The motorist, whose name was not released, was treated for a puncture wound.
Gibson is charged with aggravated assault and possession of a weapon.