New York Codes, Rules and Regulations
Title 15 - Department of Motor Vehicles
Chapter I - REGULATIONS OF THE COMMISSIONER
Subchapter B - Registration, Certificate of Title, and Number Plates
Part 17 - Number Plates
Section 17.5 - Number plates of the state, twy and official series

Number plates of the State series which bear two numerals designating the model year of the vehicle followed by four numerals issued for vehicles owned by the State, number plates which bear the letters TWY followed by numerals issued for vehicles owned by the New York State Thruway Authority, and number plates which bear five numerals followed by a letter issued for vehicles owned by political subdivisions and public authorities of this State shall be continued in use until otherwise prescribed by the commissioner. No validating sticker will be required to be affixed to such plates.