N.Y. Comp. Codes R. & Regs. tit. 17, § 720.3
(10) Route signs. Each bus operated in city service, where more than two routes are operated, shall display a number, symbol or letter to distinctly indicate the specific route or destination.
(b) School vehicles with capacity of eight or more passengers.
(1) School vehicle signs. Pursuant to the section 375 of the Vehicle and Traffic Law, every vehicle having a seating capacity of eight or more passengers, when used exclusively to transport pupils, teachers and other persons acting in a supervisory capacity to and from school or school activities, or to transport children, instructors or other persons acting in a supervisory capacity to and from child care centers maintained for migrant farm and food processing laborers or to transport children, instructors or other persons acting in a supervisory capacity to and from camp or camp activities, or to transport children, instructors or other persons acting in a supervisory capacity to and from religious service or instruction shall be equipped with one sign on the front and sign on the rear, bearing the inscription SCHOOL BUS. Such sign must comply with the following:
(2) Telephone number. All school buses purchased, leased or acquired on or after September 1, 1997, shall have the telephone number, including the area code, of the owner and/or operator printed in three inch bold type on the rear of such vehicle to the extent practical. Other school buses may have such information on the rear of the bus if so desired by the operator.
(c) Exceptions.
Vehicles which do not receive or discharge passengers on or along the public highways. Such vehicles may be exempt from the requirements of subdivision (b) of this section provided that the operator of such vehicle certifies to the department in writing that the vehicle does not receive or discharge passengers on or along any public highway. Such certification shall be provided to and shall only be approved by an authorized department representative if the intended use of such a vehicle is not inconsistent with the provisions of the National Traffic Motor Vehicle Safety Act of 1974 with respect to the use of new vans with a seating capacity of more than 10 persons, including the driver, for school transportation.
(d) Signs and placards.
Any motor vehicle having a seating capacity of more than seven passengers and whose primary use is to transport pupil(s) and teachers to and from school shall not be mounted with or have installed thereon any sign, placard, or other display except as permitted by law. The provisions of this subdivision shall not apply to such motor vehicles operating in a city with a population of one million or more.
(a) General requirements (all vehicles).