N.J. Admin. Code § 13:20-1.2 : LAW AND PUBLIC SAFETY — ENFORCEMENT SERVICE — STANDARDS AND SPECIFICATIONS GOVERNING THE TYPES OF SUN-SCREENING MATERIALS AND PRODUCTS THAT MAY BE INSTALLED OR APPLIED TO WINDSHIELDS AND FRONT SIDE WINDOWS OF MOTOR VEHICLES FOR WHICH MEDICAL EXEMPTION CERTIFICATES HAVE BEEN ISSUED; STANDARDS GOVERNING THE ISSUANCE OF MEDICAL EXEMPTION CERTIFICATES —1.2 - Light transmittance standard; motor vehicle windshield and front side windows

(a) Sun-screening materials and products shall not be installed or applied to the windshield of a motor vehicle which, in conjunction with factory-installed glazing, reduce the transmittance of normally incident visible light below 70 percent.
(b) Notwithstanding (a) above, sun-screening materials and products may be installed or applied to that portion of the windshield of a motor vehicle above the AS-1 line which, in conjunction with factory-installed glazing, reduce the transmittance of normally incident visible light below 70 percent.
(c) Sun-screening materials and products shall not be installed or applied to the front side window(s) of a motor vehicle which, in conjunction with factory-installed glazing, reduce the transmittance of normally incident visible light below 60 percent.
(d) Notwithstanding (c) above, the owner or lessee of a motor vehicle for which a medical exemption certificate has been issued pursuant to this subchapter may affix readily removable sun-screening materials and products to the uppermost six-inch portion of the front side window(s) of such motor vehicle during the hours between sunrise and sunset; provided, however, that such readily removable sun-screening materials and products shall not, in conjunction with factory-installed glazing, reduce the transmittance of normally incident visible light below 35 percent.

N.J. Admin. Code § 13:20-1.2