Here is what the law says, although what individual police choose to actually enforce will certainly vary.
This is Section 375, subdivision 12-a, paragraphs (b) through (f) of the New York State Vehicle and Traffic Law:
12-a. (b) No person shall operate any motor vehicle upon any public highway, road or street:
(1) the front windshield of which is composed of, covered by or treated with any material which has a light transmittance of less than seventy percent unless such materials are limited to the uppermost six inches of the windshield; or
(2) the sidewings or side windows of which on either side forward of or adjacent to the operator's seat are composed of, covered by or treated with any material which has a light transmittance of less than seventy percent; or
(3) if it is classified as a station wagon, sedan, hardtop, coupe, hatchback or convertible and any rear side window has a light transmittance of less than seventy percent; or
(4) the rear window of which is composed of, covered by or treated with any material which has a light transmittance of less than seventy percent. A rear window may have a light transmittance of less than seventy percent if the vehicle is equipped with side mirrors on both sides of the vehicle so adjusted that the driver thereof shall have a clear and full view of the road and condition of traffic behind such vehicle.
(c) Any person required for medical reasons to be shielded from the direct rays of the sun and/or any person operating a motor vehicle belonging to such person or in which such person is an habitual passenger shall be exempt from the provisions of subparagraphs one and two of paragraph (b) of this subdivision provided the commissioner has granted an exemption and notice of such exemption is affixed to the vehicle as directed by the commissioner. The applicant for such exemption must provide a physician's statement with the reason for the exemption, the name of the individual with a medically necessary condition operating or transported in the vehicle, the specific condition involved, and the minimum level of light transmission required. The commissioner shall only authorize exemptions where the medical condition certified by the physician is contained on a list of medical conditions prepared by the commissioner of health pursuant to subdivision sixteen of section two hundred six of the public health law. If such such exemption is granted, the commissioner shall make a record thereof and shall distribute a sufficiently noticeable sticker to the applicant to be attached to any window so shielded or altered pursuant to such exemption.
(d) The commissioner may test any window for a person who has been charged with violating this subdivision. If such window is found to be in conformity with this subdivision, a small label attesting to the conformity shall be affixed to the window tested.
(e) On and after January first, nineteen hundred ninety-two, no person shall manufacture, sell, offer for sale, equip or operate a motor vehicle in this state in violation of the provisions of this subdivision, except that a person may operate a nineteen hundred ninety one or earlier model year vehicle without violating this subdivision if the windows on said vehicle were in conformity with this subdivision as it existed on December thirty-first, nineteen hundred ninety-one.
(f) The commissioner shall make such rules and regulations as he shall deem necessary to carry out the provisions of this subdivision.
