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 29 - County Motor Vehicle Use Taxes
Section 29.9 - Notification as to litigation

The commissioner shall promptly notify the appropriate legal officer of the county and the appropriate fiscal officer of the county shall promptly notify the deputy commissioner and counsel of DMV, of any litigation instituted against either party which challenges the constitutionality or validity of the local law imposing the tax or of the enabling act under which it was adopted, or which attempts to limit or question the applicability of either such law; and such notification shall include a copy of the papers served upon either party.