N.Y. Comp. Codes R. & Regs. tit. 15, § 26.2
(a) Van pool operation.
Only vehicles used in a van pooling operation shall be eligible for van pool plates. Van pooling means the prearranged transportation of persons to and from their places of employment or other destination on a regular daily basis provided that any monies paid by the passengers to the van pool vehicle owner, lessee or operator are solely for the recovery of some or all expenses related directly to the transport of the passengers, including tolls, fuel, insurance and depreciation on a not-for-profit basis.
(b) Vehicle size.
Only vehicles which have an adult seating capacity of not less than six and not more than fifteen passengers in addition to the driver may qualify for van pool plates. Ordinary passenger vehicles will not qualify for van pool plates. Suburban (station wagon) type vehicles will qualify for van pool plates only if such vehicle is equipped with enough seats to accommodate not less than six and not more than fifteen passengers.