Interpretation ID: 2171y
Chairman, Committee on Energy and Commerce
United States House of Representatives
Washington, DC 20515
Dear Mr. Chairman:
Thank you for your letter of September 22, 1989, forwarding Representative Morella's letter inquiring about the requirements of Federal law and regulations as they apply to the tinting of motor vehicle windows for medical reasons. We recently began a rulemaking proceeding on the issue of tinting, and I welcome this opportunity to discuss the matter.
The enclosures to Ms. Morella's letter described a case in which a person suffers from a skin disease called vitiligo and was advised to avoid exposure to the sun's rays. The presumption is that this person needs more protection from the sun than that afforded by vehicle windows that conform to the Federal standard.
Federal Motor Vehicle Safety Standard No. 205, Glazing Materials, establishes a minimum 70 percent light transmissibility for glazing at levels "requisite for driving visibility," which includes all windows in passenger cars. When a requirement is established in a Federal safety standard, the National Traffic and Motor Vehicle Safety Act prohibits any person from manufacturing, selling, or importing a new vehicle that does not comply with that requirement. The Safety Act does not provide for individual medical exemptions.
Similarly, the Safety Act prohibits any manufacturer, distributor, dealer, or repair business from "rendering inoperative" an element of design required by a safety standard, such as minimum light transmissibility. This "render inoperative" prohibition applies to vehicles after sale to purchasers. Neither this "render inoperative" provision nor any other Federal requirement would prohibit an individual vehicle owner from modifying their own vehicles, even if the modifications cause the vehicle to no longer comply with the Federal safety standards. Thus, an individual vehicle owner can make whatever modifications he or she likes, for medical or any other reasons, without violating Federal law. However, the individual States have the authority to regulate modifications that owners may make to their vehicles, and many States have chosen to regulate window tinting. For your reference, I have enclosed copies of our July 8, 1988 letter to Representative Shumway and our November 1, 1988 letter to Representative Byron on this subject.
The minimum light transmissibility requirement in Standard No. 205 represents a balancing of legitimate competing interests. On the one hand, safety considerations dictate that drivers must be able to see and analyze the traffic situation in which the vehicle is being operated and react to that situation properly and promptly. To the extent that some of the available light is not transmitted through the vehicle glazing, the driver's ability to react to the traffic situation is potentially delayed. This is especially true under low light conditions, such as occur at night and on very overcast days.
On the other hand, there are legitimate reasons for allowing some tinting of vehicle windows. These include avoiding excessive heat for all vehicle occupants, reducing glare for the driver, preserving the vehicle interior, and helping persons with medical conditions that are sensitive to the sun's rays.
NHTSA balanced these competing interests by establishing the current 70 percent minimum light transmissibility requirement in Standard No. 205. However, the agency was asked in a petition for rulemaking to reexamine this balance and to permit darker tinting of windows, by lowering the minimum light transmissibility requirement. We decided to reexamine whether the current minimum light transmissibility requirement continues to represent the most appropriate and reasonable balance of the competing interests.
Accordingly, on July 20, 1989, this agency published a request for comments on a comprehensive review of the 70 percent light transmissibility requirement for side and rear window glazing in passenger automobiles. One of the issues raised was the light transmissibility standard's effect on those who need more protection from the sun's ultraviolet rays. The comment period for this notice closed on September 18, 1989. The agency received nearly one hundred comments on this issue and is currently reviewing those comments. We will notify you and Ms. Morella when we announce our decision.
I have placed a copy of your letter and this response in the public docket for this rulemaking action. I hope this information is helpful.
Sincerely,
Jeffrey R. Miller Acting Administrator
Enclosures
cc: The Honorable Constance A. Morella
ref:205 d:ll/20/89