A placard shall be placed on the extreme left side (usual driver side) of the rear facing portion of the rear bumper. If a vehicle lacks a bumper, the placard shall be mounted at least 15 inches, but not more than 30 inches, above the ground near the left side (usual driver side) of the rear of the vehicle. A vehicle may have additional placards.
N.Y. Comp. Codes R. & Regs. Tit. 15 § 70.5