Utah Code Ann. § 41-6a-1635 – Windshields and windows -- Tinting -- Obstructions reducing visibility -- Wipers -- Prohibitions.

(1) Except as provided in Subsections (2) and (3), a person may not operate a motor vehicle with:
1. (a) a windshield that allows less than 70% light transmittance;
2. (b) a front side window that allows less than 43% light transmittance;
3. (c) any windshield or window that is composed of, covered by, or treated with any material or component that presents a metallic or mirrored appearance; or
4. (d) any sign, poster, or other nontransparent material on the windshield or side windows of the motor vehicle except:
  1. (i) a certificate or other paper required to be so displayed by law; or
  2. (ii) the vehicle's identification number displayed or etched in accordance with rules made by the department under Section 41-6a-1601.
(2) Nontransparent materials may be used:
1. (a) along the top edge of the windshield if the materials do not extend downward more than four inches from the top edge of the windshield or beyond the AS-1 line whichever is lowest;
2. (b) in the lower left-hand corner of the windshield provided they do not extend more than three inches to the right of the left edge or more than four inches above the bottom edge of the windshield; or
3. (c) on the rear windows including rear side windows located behind the vehicle operator.
(3) A windshield or other window is considered to comply with the requirements of Subsection (1) if the windshield or other window meets the federal statutes and regulations for motor vehicle window composition, covering, light transmittance, and treatment.
(4) Except for material used on the windshield in compliance with Subsections (2)(a) and (b), a motor vehicle with tinting or nontransparent material on any window shall be equipped with rear-view mirrors mounted on the left side and on the right side of the motor vehicle to reflect to the driver a view of the highway to the rear of the motor vehicle.
(5)
1. (a)
  1. (i) The windshield on a motor vehicle shall be equipped with a device for cleaning rain, snow, or other moisture from the windshield.
  2. (ii) The device shall be constructed to be operated by the operator of the motor vehicle.
2. (b) A windshield wiper on a motor vehicle shall be maintained in good working order.
(6) A person may not have for sale, sell, offer for sale, install, cover, or treat a windshield or window in violation of this section.
(7) Notwithstanding this section, any person subject to the federal Motor Vehicle Safety Standards, including motor vehicle manufacturers, distributors, dealers, importers, and repair businesses, shall comply with the federal standards on motor vehicle window tinting.