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: aiam4337OpenThe Honorable Ted Stevens, United States Senate, Washington, DC 20510; The Honorable Ted Stevens United States Senate Washington DC 20510; Dear Senator Stevens: Thank you for your April 23, 1987, letter on behalf of you constituent, Ms. Nadra L. Angerman of Wrangell, who is concerned that there is no Federal requirement for safety belts on school buses. Your letter has been referred to my office for reply, since the National Highway Traffic Safety Administration (NHTSA) is responsible for administering Federal programs relating to school bus safety.; I appreciate this opportunity to respond to Ms. Angerman's concerns. A explained below, NHTSA does not require large school buses to have safety belts for passengers because we require those buses to provide an alternate form of passenger crash protection. Our safety standards are directed at improving the interior of large school buses so that passengers will be provided adequate crash protection even if safety belts are not used.; I would like to begin with some background information on our schoo bus regulations. NHTSA is responsible for developing safety standards applicable to all new motor vehicles, including school buses. In 1977, we issued a set of motor vehicle safety standards for various aspects of school bus safety. Included in that set is Federal Motor Vehicle Safety Standard No. 222, *School Bus Passenger Seating and Crash Protection.* Standard No. 222 requires large school buses--i.e., those with gross vehicle weight ratings over 10,000 pounds--to provide passenger crash protection through a concept called 'compartmentalization.' Compartmentalization refers to designing the interior of large buses so that children are protected regardless of whether they have fastened a safety belt. The key features include higher and stronger seat backs, additional seat padding, and better seat spacing and performance.; Our safety standards require a safety belt for the school bus drive since the driver's position is not compartmentalized. We also require safety belts for passengers in smaller school buses because those buses experience greater crash forces than do larger buses.; However, because large school buses already offer substantia protection to passengers, we believe a Federal requirement for safety belts in those vehicles is unnecessary. Large school buses are very safe vehicles not only because they meet Federal school bus safety standards, but also because of their size and weight, the training and experience of their drivers and the extra care that other road users employ in the vicinity of school buses. TSA does not prevent States and local jurisdictions that wish to order safety belts on their own large school buses from doing so. Such a decision is a matter for the officials of the particular State or local jurisdiction, who are best able to assess their own preferences regarding pupil transportation.; A June 1985 NHTSA publication entitled, 'Safety Belts in School Buses, discusses many of the issues relating to safety belts in large school buses. I have enclosed a copy of the report for your information.; I hope you have found this information to be helpful. If you or you constituent have any further questions, please do not hesitate to contact me.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3558OpenDale R. Martin, Esq., Secretary and Counsel, Motor Wheel Corporation, Lansing, MI 48909; Dale R. Martin Esq. Secretary and Counsel Motor Wheel Corporation Lansing MI 48909; Dear Mr. Martin: This responds to your recent letter to Mr. Kratzke of my staff requesting an interpretation concerning Federal Motor Vehicle Safety Standard No. 120 (49 CFR S 571.120). Specifically, you noted that your company, a wholly-owned subsidiary of Goodyear, wants to import rims from Lemmerz, a West German manufacturer, and mark those rims with the Goodyear name and trademark. This would be similar to the tires sold, for example, with Sears or Montgomery Ward labels and trademarks on the sidewalls. Your question concerns the requirement in section S5.2(d) of Standard No. 120, which specifies that each rim be marked with 'a designation that identifies the manufacturer of the rim by name, trademark, or symbol.' You correctly recognized that Lemmerz would have to be identified as the actual manufacturer, and asked if the block letter 'L' would be a sufficient identification. Imprinting an 'L' on the rims manufactured for Goodyear by Lemmerz would satisfy the requirement of Standard No. 120.; In the notice initially establishing Standard No. 120 (41 FR 3478 January 23, 1976), this agency stated, 'The rim manufacturer is free to use his name, trademark, or a symbol of his choice.' The only limitation on this freedom is that the information cannot be presented in a deceptive or confusing manner. In the circumstances you have described, a consumer with a complaint or problem with the rims would know to contact Goodyear about the rims, and Goodyear would know that the block letter 'L' indicated that the rim had been manufactured for them by Lemmerz. This would not be confusing or deceptive. Hence, the purpose of the labeling requirement is fulfilled, so Goodyear is free to use the letter 'L' as the indicator that the rim was actually manufactured by Lemmerz.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1565OpenMr. Ronald J. Hansing, Project Engineer, The Adams & Westlake Company, 1025 North Michigan Street, Elkhart, IN 46514; Mr. Ronald J. Hansing Project Engineer The Adams & Westlake Company 1025 North Michigan Street Elkhart IN 46514; Dear Mr. Hansing: This is in reply to your letter of July 3, 1974, regarding Moto Vehicle Safety Standard No. 217. You requested that we reconsider our opinion of June 11, 1974, that a bus emergency release mechanism which you describe must meet the requirements for emergency exit release in S5.3.2 of the standard after as well as before the retention test required by S5.1, when the glass breaks during the retention test.; Paragraph S5.3.2 requires that the release requirements be met bot before and after the retention test. We do not find sufficient justification to relax this requirement in the situation you described. First, it is not clear that it is as easy as you represent to eliminate by hand all of the glazing material left in the frame. More importantly, however, we still question whether most persons are sufficiently cognizant of the qualities of tempered glass to attempt to remove the remaining fragments in an emergency situation. Finally, glazing with completely different breakage characteristics may be used to replace the original tempered glass at some time during the life of the bus. For these reasons, our conclusion of June 11 remains the same.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4767OpenMs. Betsy Dittemore Legislative Liaison Iowa Department of Public Safety Office of the Commissioner Wallace State Office Building Des Moines, Iowa 50319; Ms. Betsy Dittemore Legislative Liaison Iowa Department of Public Safety Office of the Commissioner Wallace State Office Building Des Moines Iowa 50319; "Dear Ms. Dittemore: Thank you for your letter regarding a bil introduced in the Iowa Senate that, among other features, would establish light transmittance limits for 'sunscreening devices' that may be applied to the windows of motor vehicles operated in Iowa. I apologize for the delay in this response. You requested our office's interpretation about whether provisions of this bill would violate or be preempted by Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205). As you are aware, this agency is authorized by section 103 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1392) to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. One of the standards that we have issued under this authority is Standard No. 205, which applies to all new vehicles and all new glazing materials for use in motor vehicles. Among the requirements set forth in Standard No. 205 are specifications for minimum levels of light transmittance (70 percent light transmittance in areas requisite for driving visibility, which includes all windows in passenger cars). Section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) specifies that no person may manufacture, import, or sell any vehicle in the United States unless it is in conformity with all applicable safety standards. Pursuant to section 108(b)(1) of the Safety Act (15 U.S.C. 1397(b)(1)), this prohibition no longer applies after the vehicle is sold to a consumer. However, both before and after the first sale, section 108(a)(2) of the Safety Act (15 U.S.C. 1397(a)(2)) provides that 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a notor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard . . . .' In the case of windows on a passenger car, this provision of Federal law means that no manufacturer, dealer, distributor, or repair business could install window tinting film that would result in a light transmittance of less than 70 percent for any window of the car, because such action would 'render inoperative' the vehicle's compliance with Standard No. 205. This same provision of Federal law prohibits a service station from permanently removing safety belts or permanently disconnecting brake lines on motor vehicles. Please note that the Safety Act does not apply to the actions of vehicle owners. Vehicle owners may alter their own vehicles and operate them on the highways as they please, even if the vehicle's windows no longer comply with the requirements of Standard No. 205. Hence, no provision of a Federal statute or this agency's regulations prevents individual vehicle owners themselves from tinting the windows on their vehicles. The individual States, however, have the authority to regulate the modifications that vehicle owners may make to their own vehicles and to establish requirements for vehicles operated or registered in that State. The Iowa Senate bill enclosed with your letter appears to be an attempted exercise of this inherent authority. You asked for comments on whether this bill, if adopted as law in Iowa, would be preempted by Standard No. 205. I assume you were referring to the provision in this Iowa bill that would prohibit the operation of motor vehicles required to be registered in the State of Iowa if the vehicle has a 'sunscreening device' on the front side windows with light transmittance of less than 35 percent or on the rear window and side windows behind the driver with light transmittance of less than 20 percent. Since the original glazing on the vehicle could have had light transmittance of as little as 70 percent, this provision would permit overall light transmittance levels of as low as 25 percent for the front side windows and 14 percent for the rear windows. This provision in the Iowa bill, and similar provisions in statutes adopted by other States, does not purport to legitimize conduct -- the rendering inoperative of glazing by firms installing window tinting -- that is illegal under Federal law. In other words, firms installing window tinting that results in light transmittance of less than 70 percent on any window of a passenger car would have violated the 'render inoperative' provision in Federal law, even if Iowa had in place a statute that would permit persons to operate and register vehicles whose windows had light transmittance that was far lower. Conversely, the Federal law setting requirements for the manufacture and sale of new vehicles and limiting the modifications commercial enterprises can make to those vehicles does not prohibit the State of Iowa from establishing lesser limits on owner modifications to their own vehicles and as the minimum requirements for vehicles to be operated and registered in the State of Iowa. Thus, there does not appear to be any legal conflict between Federal law and this Iowa bill, and Iowa would be free to enforce the provisions of this bill if it is enacted into law. We would, however, urge the State of Iowa to carefully consider the adverse safety consequences that would result from enacting this bill into law. NHTSA has determined that a 70 percent light transmittance minimum for new vehicles is the appropriate level to assure motor vehicle safety. Your letter indicated that Iowa had also adopted this 70 percent light transmittance minimum as a State requirement for new vehicles. It is not clear why the State of Iowa would conclude that the safety need that justifies requiring not less than 70 percent light transmittance in new vehicles is satisfied by allowing light transmittance levels as low as 25 and 14 percent in vehicles to be operated in the State. I hope that this information is helpful. If you have any further questions or need 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, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0724OpenMr. B. Fechner: (sic), FMC Corporation, Recreational Vehicles Division, 333 Brokaw Road, Box 664, Santa Clara, CA 95052; Mr. B. Fechner: (sic) FMC Corporation Recreational Vehicles Division 333 Brokaw Road Box 664 Santa Clara CA 95052; Dear Mr. Fechner:#This is in reply to your letter of May 25 inquirin about compliance of your planned motorhome with Federal Motor Vehicle Safety Standards Nos. 101 and 104.#Standard No. 101 requires certain controls to be illuminated. We interpret this to mean sufficiently illuminated that the control identification, if verbal, can be read, or if pictorial, can be understood. Therefore, illumination from any course is satisfactory as long as the basic requirement of comprehension is met.#Standard No. 104 does not describe the type of windshield wiping system that must be used to meet its requirements. It is the manufacturer's responsibility to insure, whatever system is used and whatever configuration of windshield is employed, that the wiped and washed area requirements are met.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam1374OpenHonorable John W. Davis, House of Representatives, Washington, DC 20515; Honorable John W. Davis House of Representatives Washington DC 20515; Dear Mr. Davis: This is in reply to your letter of December 17, 1973, on behalf of Ms Judith Davis, who has suggested the incorporation of the Federal odometer form into the bill of sale as a means of reducing paperwork in motor vehicle transactions.; Although the Federal odometer disclosure regulation requires the selle to give the buyer several items of information that we consider essential to adequate disclosure, the regulation does not require the use of a separate form. If Ms. Davis is able to include the required information in the bill of sale used by the Rome Auto Auction, she may do so. Information items that are common to the bill of sale and the disclosure statement, such as the model and make of the vehicle, would not have to be stated twice.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4176OpenMr. Larry H. McEntire, Administrator, School Transportation, Florida Department of Education, Tallahassee, FL 32301; Mr. Larry H. McEntire Administrator School Transportation Florida Department of Education Tallahassee FL 32301; Dear Mr. McEntire: I regret the delay in responding to your letter to this office askin whether certain 'mini-vans' designed to carry a maximum of eight persons are classified by NHTSA as 'passenger cars' or 'multipurpose passenger vehicles' (MPV's), for purposes of complying with the Federal motor vehicle safety standards.; I would like to begin by clarifying that the classification of particular vehicle is determined in the first instance by its manufacturer, and not by NHTSA. Under our certification requirements (49 CFR Part 567), manufacturers are required to specify the type of their vehicles in accordance with the definitions set forth in Part 571.3 of our regulations and must certify that their motor vehicles comply with all the motor vehicle safety standards applicable to that type. We define an MPV in Part 571.3 as 'a motor vehicle ... designed to carry 10 persons or less which is constructed either on a truck chassis or with special features for occasional off-road operation.'; Information we have received regarding manufacturer certificatio discloses that manufacturers classify *cargo- carrying* models of the Ford Aerostar, and G.M. Astro and Safari as 'trucks.' A 'truck' is defined in Part 571.3 as 'a motor vehicle...except a trailer, designed primarily for the transportation of property or special purpose equipment.' We understand that *passenger* models of mini-vans designed to carry up to eight passengers utilize the same type of chassis used in truck models. It is likely, therefore, that the passenger model mini-vans you asked about would be classified as MPV's instead of passenger cars. This is verified by the 'MPV' classification given by manufacturers to the Chrysler mini-van and Toyota Van.; On a related matter, you asked for our comments on your Department' recommendation to your school boards that they not condone parents' use of conventional vans (i.e., vans not meeting Federal or State school bus safety regulations) to transport school children to school-related events. Mr. Arnold Spencer of Rockledge, Florida, recently wrote to our office concerning the above recommendation and requested us to explain how our school bus regulations apply to persons owning vans. I have enclosed a copy of our April 25, 1986, response to Mr. Spencer which you might find helpful.; I hope this information is helpful. If you have further questions please feel free to contact us.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0836OpenMr. Jerome G. Abeles, Director, Product Planning & Purchasing, Sealy, Incorporated, 666 North Lake Shore Drive, Chicago, IL, 60611; Mr. Jerome G. Abeles Director Product Planning & Purchasing Sealy Incorporated 666 North Lake Shore Drive Chicago IL 60611; Dear Mr. Abeles: This is in reply to your letter of August 10, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to mattress assemblies.; Paragraph S4.1 of the Standard lists mattress covers only. This doe not include the complete mattress assembly. Accordingly, you are correct in your assumption that only the mattress covers must meet the burn rate requirement of Paragraph S4.3. You are also correct in your assumption that mattress assemblies which are not designed to absorb energy on contact with occupants in crash situations are not subject to the Standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3719OpenMr. Charles Jayne, Tire Manager, J-B Purchasing Corporation, P.O. Box 692, Auburn, NY 13021; Mr. Charles Jayne Tire Manager J-B Purchasing Corporation P.O. Box 692 Auburn NY 13021; Dear Mr. Jayne: This responds to your recent letter asking about the requirements of 4 CFR Part 574, *Tire Identification and Recordkeeping*. You noted that your company currently retreads tires for its own use, and that you soon plan to retread tires for sale to others. You asked if the tires you retread for your own use need to be identified with a tire identification number. The answer is no.; Section 574.5 of the Tire Identification and Recordkeeping regulatio provides, in part, that, 'Each tire retreader, *except tire retreaders who retread tires for their own use*, shall conspicuously label one sidewall of each tire he retreads by permanently molding or branding into or onto the sidewall, ...a tire identification number....' Your question concerns a situation in which a tire retreader retreads some tires for his own use and some tires for sale or lease to others. To answer your question, it is helpful to examine the purpose of the identification requirement.; The purpose of having the tire identification number labeled on th sidewall of retreaded tires is twofold. First, it enables this agency and the user of the retreaded tire to identify the retreader of the tire in the event of some safety problem with the tire. Second, it enables the tire retreader to accurately identify the retreaded tires it may have to recall. In the case of tires offered for sale or use outside your company, it is plain that both these purposes would be served by having the tire identification number on the sidewall. Therefore, Part 574 requires that each such tire have a tire identification number on one sidewall.; However, with respect to tires retreaded for the retreader's own use it is obvious who retreaded the tire, whether or not a tire identification number appears on the sidewall. Hence, the first purpose listed above would not be served by having the tire identification number on the sidewall of these tires. Further, the retreader can inspect all of the retreaded tires it uses to determine if any are subject to its recall, and assure adequate remedy for those which are within the recall, without publicizing the identification numbers of those tires. Thus, the second purpose set forth above also would not be furthered by having the tire identification number on the sidewall of these tires. Please note, however, that any tire not marked with a tire identification number can never legally be sold or otherwise offered for use outside of your company.; Should you have any further questions or need additional informatio about this topic, please contact Steve Kratzke of my staff at (202) 426-2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1724OpenNancy Kolodny, Esq., Office of the General Counsel, Ford Motor Company, The American Road, Dearborn, MI 48121; Nancy Kolodny Esq. Office of the General Counsel Ford Motor Company The American Road Dearborn MI 48121; Dear Ms. Kolodny: This is in reply to your letter of June 10, 1975, asking whether Moto Vehicle Safety Standard No. 108 preempts Section 25950 of the California Vehicle Code with respect to Mercury Monarch taillamps.; Section 25950 requires in pertinent part that all lamps visible fro the rear of a vehicle be red, 'whether lighted or unlighted', except that taillamps may be white when unlighted. Standard No. 108 requires passenger car taillamps to be 'red' (Table III), and 'the taillamp indication' to be red (SAE Standard J585, *Tail Lamps*, June 1966, incorporated by reference into Standard No. 108). The taillamps on the Mercury Monarch are covered with amber lenses. Although the lamp meets the color and photometric requirements of Standard No. 108 when lighted, California is of the opinion that use of the amber lens is prohibited by Section 25950.; Section 103(d) of the National Traffic and Motor Vehicle Safety Act o 1966 prohibits a State from establishing or continuing in effect any motor vehicle safety standard applicable to the same aspect of performance of a vehicle or equipment item as a Federal standard which is not identical to it. We interpret Standard No. 108 as requiring only that the color of the taillamp 'indication' be red. The method by which this is accomplished is left to the vehicle manufacturer. The indication could be provided by a combination of a white bulb and a red lens (the conventional taillamp), a red bulb and white lens (permitted by California) or, as in your case, a red bulb and an amber lens. Although the color of the taillamp lens is not directly specified by Standard No. 108, the performance of the lamp as an assembly is covered in detail by the standard, and we consider that the color aspects of taillamps are within the scope of these requirements. If the lamp assembly complies with the Federal standard, then a State may not prohibit its use. We therefore find that in this instance 49 CFR 571.108, Federal Motor Vehicle Safety Standard No. 108, renders void the requirement of Section 25950 of the California Vehicle Code that unlighted taillamps be colored red.; Sincerely, James C. Schultz, 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.