Trenton, NJ : police officer killed in single car crash on Thursday December 31 2015.

Gov. Chris Christie has signed an executive order for flags to be lowered to half-staff in honor of a Port Authority of New York and New Jersey police officer.
Eamonn Mautone was killed in a single-car crash early Tuesday on the New Jersey Turnpike near the state police's Cranbury barracks.
The Jackson resident graduated from the Port Authority police academy in August 2014 and was assigned to the World Trade Center command.
The executive order signed by Christie on Thursday orders flags at all state buildings to fly at half-staff on Saturday.

Source:
Flags in New Jersey to be lowered for Port Authority police officer killed in car crash