NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: aiam4676OpenMs. Linda B. Kent Senior Account Executive Market Development Fasson Specialty Division 250 Chester Street Painesville, OH 44077; Ms. Linda B. Kent Senior Account Executive Market Development Fasson Specialty Division 250 Chester Street Painesville OH 44077; "Dear Ms. Kent: Thank you for your letter requesting an interpretatio of whether the use of a product on motor vehicles would violate Standard No. 205, Glazing Materials (49 CFR /571.205). This product, called 'Contra Vision,' is designed to display messages or advertising materials on windows and other clear surfaces, so that viewers on one side of the clear surface will see the message displayed, while viewers on the other side of the surface will see an essentially transparent surface without any message visible. According to your letter, this product 'will be used for promotional signage in store windows, but also has application in rear taxicab windows, as well as rear and side windows of city buses.' You asked for our opinion of whether this product complies with Standard No. 205. Some background on how Federal motor vehicle safety laws and regulation affect this product may be helpful. Our agency is authorized under the National Traffic and Motor Vehicle Safety Act to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. NHTSA, however, does not approve or certify any vehicles or items of equipment, nor do we endorse any commercial products or processes. Instead, the Safety Act specifies that each manufacturer itself must certify that its products meet all applicable safety standards. The agency periodically tests vehicles and items of equipment for compliance with the standards, and also investigates alleged defects related to motor vehicle safety and alleged violations of other statutory provisions. Your letter indicates that you are already aware that NHTSA has issued a safety standard that applies to the windows installed in motor vehicles. Specifically, Standard No. 205 requires that all new vehicles and all new glazing materials for use in motor vehicles must comply with certain performance requirements. Among the requirements set forth in Standard No. 205 are specifications for minimum levels of light transmittance. A minimum of 70 percent light transmittance is required in glazing areas requisite for driving visibility, which includes all windows in passenger cars. In trucks and buses, the windshield and windows to the immediate right and left of the driver and the rearmost window, if the latter is used for driving visibility, are considered to be requisite for driving visibility, and therefore subject to the 70 percent minimum light transmittance requirement. Your letter did not provide any information on the light transmittance that would be measured through glazing with Contra Vision installed on it. The combination of the glazing material and the Contra Vision must allow at least 70 percent light transmittance to comply with the requirements of Standard No. 205. No manufacturer or dealer is permitted to install Contra Vision on the glazing materials on new vehicles, unless the manufacturer or dealer certifies that the vehicle continues to comply with the 70 percent minimum light transmittance and other requirements of Standard No. 205. After a vehicle is first sold to a consumer, modifications to the vehicle are affected by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, dealer, distributor, or repair business from 'rendering inoperative' any device or element of design installed in a vehicle in compliance with any safety standard. This provision of the law means that no manufacturer, dealer, distributor, or repair business could install Contra Vision if the addition of Contra Vision to the glazing would result in a light transmittance of less than 70 percent, or otherwise cause the vehicle to no longer comply with the applicable requirements of Standard 205. Violations of this 'render inoperative' prohibition can result in Federal civil penalties to the manufacturer, dealer, distributor, or repair business of up to $1000 for each noncomplying installation. Section 108(a)(2)(A) of the Safety Act does not affect vehicle owners. Hence, vehicle owners themselves may install Contra Vision or any other product on the glazing of their vehicle, regardless of whether the installation causes the vehicle to no longer comply with Standard No. 205. Individual States have the authority to regulate the operational use of vehicles by their owners, and, therefore, have the authority to regulate or preclude individual owner modifications to the glazing of their vehicles. I have enclosed an information sheet that summarizes the relationship between Federal auto safety laws and motor vehicle window tinting. I hope this information is helpful. If you have any further questions or need any additional information about this topic, please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure"; |
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ID: aiam3019OpenMr. Eugene S. Trioli, 24 Wedgemere Road, Malden, MA 02148; Mr. Eugene S. Trioli 24 Wedgemere Road Malden MA 02148; Dear Mr. Trioli: This responds to your recent letter requesting information concernin the Federal requirements that would be applicable to auxiliary propane fuel systems for automobiles, which you would like to market in the United States.; Federal Motor Vehicle Safety Standard No. 301-75, *Fuel Syste Integrity*, (copy enclosed) specifies performance requirements for fuel systems on motor vehicles. Although the standard applies to completed vehicles rather than to fuel tanks or other fuel system components, there are requirements of which you should be aware if you intend to market auxiliary fuel systems. An original vehicle manufacturer that uses your auxiliary system, General Motors for example, has to certify that the entire vehicle complies with all applicable safety standards.; A person who mounts an auxiliary fuel tank or system on a new moto vehicle before the vehicle's first purchase in good faith for purposes other than resale is a vehicle alterer under the National Highway Traffic Safety Administration regulations. That person is required by 49 CFR 567.7 (copy enclosed) to affix a label to the vehicle stating that, *as altered*, the vehicle conforms to all applicable Federal Motor Vehicle Safety Standards--including Standard No. 301-75.; In addition, the mounting of an auxiliary or replacement fuel tank on motor vehicle after the vehicle's first purchase in good faith for purposes other than resale is affected by Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act of 1966, as amended (15 U.S.C. 1397(a)(2)(A)). That section specifies in relevant part that:; >>>No manufacturer, distributor, dealer, or motor vehicle repai business shall *knowingly render inoperative*, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard.... (Emphasis added.)<<<; Therefore, the mounting of an auxiliary fuel tank or system on a use vehicle must be performed in such a way that the vehicles's compliance with Standard No. 301-75 is not knowingly compromised.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1024OpenMr. R. L. Brown, President, Brown Motor Co., Inc., 1005 S. Main Street, Corbin, KY 40701; Mr. R. L. Brown President Brown Motor Co. Inc. 1005 S. Main Street Corbin KY 40701; Dear Mr. Brown: I am returning herewith copies of two odometer disclosure statement executed by your company on February 15 and 17, 1973. Our regulations require you to submit these statements to each customer, but they do not require you to send us a copy. I suggest that you retain the enclosed copies for your files.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4226OpenMs. Lisa Kreeger, Reichert, Strauss & Reed, 2510 Carew Tower, Cincinnati, OH 45202; Ms. Lisa Kreeger Reichert Strauss & Reed 2510 Carew Tower Cincinnati OH 45202; Dear Ms. Kreeger: This responds to your letters of June 27, 1986, and July 11, 1986, an your subsequent phone conversations with Stephen Oesch of my staff concerning the safety belt installation requirements for multipurpose passenger vehicles and buses. I regret the delay in our response and hope the following information is of assistance to you.; As Mr. Oesch discussed with you, Federal Motor Vehicle Safety Standar No. 208, *Occupant Crash Protection*, sets forth the safety belt installation requirements for passenger cars, trucks, multipurpose passenger vehicles and buses. The standard, a copy of which is enclosed, regulates only the installation of safety belts and does not require their use. However, the Federal Highway Administration's Office of Motor Carriers has issued a regulation (49 CFR Part 392.16) that requires safety belt use by operators of trucks and buses involved in interstate commerce. Belt use is also governed by State mandatory use laws.; S4.2.2 and S4.3 of the standard set forth the safety belt installatio requirements for new multipurpose passenger vehicles (MPV's). Our regulations (49 CFR 571.3) define an MPV as a 'motor vehicle with motive power, except a trailer, designed to carry 10 persons or less which is constructed either on a truck chassis or with special features for occasional off-road operation.' S4.2.2 and S4.3 of Standard No. 208 require the installation of a safety belt for each designated seating position in a MPV.; S4.4 of the standard sets forth the safety belt installatio requirements for buses. Our regulations define a bus as a 'motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons.' S4.4 of Standard No. 208 requires the installation of a safety belt at only the driver's designated seating position in a bus. The agency has set additional safety belt requirements for school buses with a gross vehicle weight rating of 10,000 pounds or less. S5(b) of Standard No. 222, School bus passenger seating and crash protection, requires the installation of a safety belt at the passenger seats in those small school buses. A copy of Standard No. 222 is enclosed.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4508OpenMr. R. H. Madison 12814 Asbury Drive Ft. Washington, MD 20744; Mr. R. H. Madison 12814 Asbury Drive Ft. Washington MD 20744; "Dear Mr. Madison: This responds to your March 31, 1988, letter askin for our interpretation of Safety Standard No. 207, Seating Systems, as it applies to a seat installed in a multipurpose passenger vehicle and equipped with a safety belt. You attached a sketch of your seat and asked whether the safety belt assembly is considered to be attached to the seat. You asked this question in order to determine whether the seat would be subject to the specified forces of paragraph S4.2(c) of the standard. The answer is that NHTSA considers the assembly to be attached to the seat. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not grant approval of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with applicable requirements. The following represents our opinion based on our understanding of the facts provided in your letter. In this regard, I want to note that rendering an opinion in this case was complicated by the fact that your sketch does not show the seat structure and its interrelationship with the vehicle structure and belt anchorage. In your letter, you refer to a vehicle having a 'Belt Attachment Frame' made from steel members attached to the vehicle's structure. You said that, '(r)esting on the Belt Attachment Frame is a plywood deck . . . The seat cushion rests on but is not otherwise attached to the deck. The seat belt attachments pass through the deck and are secured to the Belt Attachment Frame. Other portions of the seat or its supporting structure might rest on and contact the Belt Attachment Frame and might extend to or beyond it. However, except for the deck, no part of the seat or its structural members would be attached to the Belt Attachment Frame.' (Emphasis added.) The answer to your question depends on whether the Belt Attachment Frame is considered part of the seat. Based on the information you provide, we conclude that the Belt Attachment Frame is part of the seat itself. According to your letter, the deck for the seat cushion is attached to and supported by the Belt Attachment Frame, it appears that the Belt Attachment Frame is a necessary and functional part of the seat structure. Since we interpret the Belt Attachment Frame to be a part of the seat, and since the seat belt assembly loads will be transferred to the Frame in the event of a crash, we consider the seat belt assembly to be attached to the seat, for purposes of testing the seat under S4.2(c) of Standard No. 207. Please contact my office if you have further questions. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3737OpenMr. H. Le Guen, Laboratory Director, Union Technique de L'Automobile du Motorcycle et du Cycle, Autodrome de Linas- Montlhery, Linas, 91310 Montlhery, France; Mr. H. Le Guen Laboratory Director Union Technique de L'Automobile du Motorcycle et du Cycle Autodrome de Linas- Montlhery Linas 91310 Montlhery France; Dear Mr. Le Guen: This is in reply to your letter of July 27, 1983, to Mr. Vinson of thi office asking several questions with respect to the amendment of Standard No. 108, June 2, 1983, which permits semi-sealed replaceable bulb headlamps.; First, you mention certain sealing specifications, contrasting the with references to designed openings, and ask for our comments on this. Although the design that Ford intends to use is not a vented system, the amendment does not specify or prohibit either vented or unvented systems. A vented system using the standardized replaceable light source and the O-ring seal is permissable (sic) if the headlamp passes all the recently adopted environmental tests.; With reference to your further questions, there are no tolerances o the dust test. You have also asked whether, assuming that a European type headlamp using the new light source 'passes all tests mentioned in the amendment to F.M.V.S.S. 108, would it get D.O.T. approval?' If the lens- reflector unit is bonded, and if with the light source inserted the lamp meets U.S. photometric requirements and all environmental tests specified in the amendment, then the manufacturer of the lamp may apply the D.O.T. symbol to it. This is the certification that the lamp meets all applicable U.S. Federal motor vehicle safety standards. Under this self- certification process, the manufacturer, rather than D.O.T., approves the lamp for sale.; Finally, you have asked who will manufacture the new bulb and where yo might be able to obtain test samples. Ford's initial supplier will be Sylvania/GTE, and you may write GTE Products Corp., West Main Street, Hillsboro, NH 03249, Attn: Mr. Richardson.; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2825OpenMr. Warren L. VanderLinden, Sales Manager, Minnesota Motor Company, P.O. Box 505, Fergus Falls, MN 56537; Mr. Warren L. VanderLinden Sales Manager Minnesota Motor Company P.O. Box 505 Fergus Falls MN 56537; Dear Mr. VanderLinden: Administrator Claybrook has asked me to respond to your recent lette concerning the installation of safety belts in the cargo area of a van vehicle for the purpose of securing wheelchair patients. Apparently, your legal counsel has advised you that such installation might be prohibited by Federal law or might give rise to private litigation problems in the future.; In answer to your questions, there is nothing under Federal law or th Federal motor vehicle safety standards that would prevent the installation of safety belts in the cargo area of a van to secure wheelchairs. In fact, Administrator Claybrook and the National Highway Traffic Safety Administration encourage you to make the installation requested by the senior citizens home. The safe transportation of disabled persons is currently a serious problem and every effort should be made to ameliorate the situation.; The only instance in which you would have any responsibilities unde Federal law would be an installation of additional safety belts prior to first purchase of the van by a consumer. In that case you would be a vehicle alteror, (sic) and under our certification regulations you would be required to place an additional label on the vehicle specifying that, as altered, the vehicle is still in compliance with all applicable safety standards (49 CFR 567.7, copy enclosed). For example, you should not destroy the vehicle's compliance with our Fuel System Integrity standard by penetrating the gas tank with the safety belt anchorage bolts.; Concerning your liability in private litigation, the general provision of negligence law would be applicable, as with any maintenance, repair or alteration done by a motor vehicle repair business. I must defer to the advice of your own counsel on that matter, however.; Once again, the agency does encourage the installation of safety belt for the securement of wheelchairs, since the disabled are seriously endangered without some type of restraint to protect them in a crash. Further, I believe that your fears of liability should be minimal as long as the installation is accomplished with normal consideration and due care.; Please contact Hugh Oates of my office if you have any furthe questions (202-426- 2992).; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0818OpenMr. Louis J. Zsoka, President, Garfield Rubber Products, Inc., 13532 Broadway Avenue, Garfield Heights, OH, 44125; Mr. Louis J. Zsoka President Garfield Rubber Products Inc. 13532 Broadway Avenue Garfield Heights OH 44125; Dear Mr. Zsoka: This is in reply to your letter of July 13, 1972, concerning th applicability of Federal Motor Vehicle Safety Standard (FMVSS) No. 302 to your sponge rubber weather-stripping for replacement.; Standard No. 302 does not apply to replacement parts or aftermarke materials. You are correct in your observation that sponge rubber weather-stripping is not included in the list of motor vehicle interior materials to which Standard No. 302 applies.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam4158OpenMr. Roger Williams, President, Technical Hallmark Enterprises, Inc., P.O. Box 103, Moss Point, MS 39563; Mr. Roger Williams President Technical Hallmark Enterprises Inc. P.O. Box 103 Moss Point MS 39563; Dear Mr. Williams: This is in reply to your letter asking about regulations applicable t the 'new lights that are now being seen on the trunk lids, and the rear windows of new automobiles'.; The specific legal name for this light is 'center high-mounted sto lamp.' It was optional for use as original equipment on passenger cars manufactured between August 1, 1984 and September 1, 1985. It has been mandatory original equipment since them. The Federal regulation that requires it is Federal Motor Vehicle Safety Standard No. 108 *Lamps, Reflective Devices, and Associated Equipment* issued by the National Highway Traffic Safety Administration of the Department of Transportation. This standard specifies color, minimum illuminated lens area, mode of operation, etc. for original equipment, and for equipment intended to replace that original equipment. The standard does not cover center high-mounted stop lamps intended for use on cars that never had them, and a manufacturer of such aftermarket motor vehicle equipment is subject only to State laws on their design, installation, and use. We encourage aftermarket manufacturers to follow the Federal standard so that the full potential of the lamp may be realized. This means that the lamp should be steady- burning rather than pulsating, and that the lens not have logos, trademarks, or other markings on it to interrupt the transmission of light from the lamp. The standard does not specify the shape of the lamp but virtually all to date have been rectangular (photos of the 1984 Cadillac Allante show a circular one), and some have exceeded the minimum requirement of a lens area of at least 4 1/2 square inches.; Noting your interest as a prospective manufacturer of these devices, enclose a copy of Standard No. 108. Sections 4.1.1.41 (page 218), Section 4.3.1.8 (page 227) and Table III (page 256) provide the relevant requirements for center high-mounted stoplamps. Should you proceed to manufacture aftermarket lamps, you would be subject to the agency's notification and remedy procedures should a safety related defect occur in them. Otherwise, you would appear to be subject only to State laws.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3367OpenMr. G. Montgomery Spindler, Uniroyal, Inc., 1700 K Street, N.W., Washington, DC 20006; Mr. G. Montgomery Spindler Uniroyal Inc. 1700 K Street N.W. Washington DC 20006; Dear Mr. Spindler: This is in response to your letter of October 10, 1980, requestin clarification of the explanation of Treadwear grading in Figure 2 of the Uniform Tire Quality Grading (UTQG) Standards (49 CFR S 575.104). You ask whether the explanation can be interpreted to mean that the relative treadwear performance of different tires on the UTQG test course in San Angelo, Texas will be consistent with the relative performance of the tires when driven under comparable conditions on other roads.; In experimental testing leading to promulgation of the UTQG regulation the National Highway Traffic Safety Administration (NHTSA) tested the treadwear of various tire lines not only on the San Angelo course but on roads in other parts of the country. The agency concluded that the UTQG grades established for different tires in testing on the San Angelo course accurately represent the relative performance of the tires obtainable on roads elsewhere in the United States, assuming that the tires to be compared are run under identical conditions.; The statement in Figure 2 of the UTQG regulation that a tire graded 15 would wear one and one-half times as well on the government course as a tire graded 100 was not intended to suggest that the tire would not wear one and one-half times as well on another course, if conditions of use were controlled. The term 'relative performance' in Figure 2 refers to the performance of tires in comparison to other tires, and the term 'norm' refers to the consistently obtainable relative performance of tires when tested under controlled conditions. Thus, the explanation indicates that, although the relative performance of different tires will be consistent when the tires are tested under controlled conditions, this relative performance may not be obtainable in actual use, if one tire is subjected to more severe road or weather conditions, abusive driving or improper maintenance.; NHTSA will provide confidential treatment for your October 10, 1980 letter.; Sincerely, Frank Berndt, Chief Counsel |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.