N.Y. Veh. & Traf. Law § 307

§ 307. Voluntary inspection. The owner of any motor vehicle, as\ndefined in article one of this chapter, whose motor vehicle is not\nrequired to be inspected and certified pursuant to this article or who\nhas previously complied therewith may, nevertheless, voluntarily comply\nwith the provisions of this article as often as he desires, and in the\nsame manner as though such inspection and certification were so\nrequired.\n