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: aiam4177OpenMr. 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: 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: aiam3847OpenMr. C. I. Nielsen III, Vice President - Marketing, Wesbar Corporation, Box 577, West Bend, WI 53095; Mr. C. I. Nielsen III Vice President - Marketing Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Nielsen: This is in reply to your letter of May 16, 1984, to Mr. Vinson of thi office seeking an interpretation of Motor Vehicle Safety Standard No. 108. You wish to know whether the minimum effective projected luminous lens area for stop lamps and turn signal lamps on trailers whose overall width is 80 inches or greater is 8 square inches or 12 square inches. You cite an apparent conflict between paragraph S4.1.1.6 and SAE Standard J586d, and paragraph S4.1.1.7 and SAE Standard J588f. You have asked for an interpretation so that Wesbar may properly design a 'combination tail lamp.'; First, we will confirm the advice provided by 'D.O.T. staff people that the latest SAE revisions, J586d and J588f, have not been adopted.; You do not state the intended use of your proposed lamp, so we wil assume that it will be sold to trailer manufacturers as original equipment, and to the aftermarket as replacement equipment. As original equipment, it must comply with the requirements specified in Table I of Standard No. 108, SAE J586c for stop lamps and SAE J588e for turn signal lamps. Paragraph 3.2 of each standard specifies a minimum effective projected luminous lens area of 8 square inches.; Paragraphs S4.1.1.6 and S4.1.1.7 become relevant, however, if Wesba intends the lamp as replacement equipment on trailers manufactured before September 1, 1978, and after January 1, 1972 (turn signal lamps) and January 1, 1973 (stop lamps). Under paragraphs S4.1.1.6 and S4.1.1.7, replacement stop and turn signal lamps for trailers manufactured within the 1972-1978 time frame may meet either J586b or J586c, and either J588d or J588e. We note that neither J586b nor paragraph S4.1.1.6 establish a minimum luminous lens area for stop lamps. However, a manufacturer who chooses to comply with paragraph S4.1.1.7 rather than J588e would have to provide the minimum specified luminous lens area of 12 square inches for turn signal lamps of trailers whose overall width was 80 inches or more, the requirement specified in J588d for Class A turn signal lamps. We view this interpretation as one of historical interest than (sic) current relevance.; In summary, if Wesbar designs its lamp to the 8-inch requirement, i would appear to meet specifications for application either as original or replacement equipment.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3318OpenMr. Dennis Newton, School Pupil Transportation, Kansas Department of Transportation, State Office Building, Topeka, KS 66612; Mr. Dennis Newton School Pupil Transportation Kansas Department of Transportation State Office Building Topeka KS 66612; Dear Mr. Newton: This responds to your June 2, 1980, letter asking whether a school bu that is to be sold to a school district in your State will meet the Federal minimum requirements applicable to gross axle weight ratings (GAWR) and gross vehicle weight ratings (GVWR).; To the best of my knowledge, the Federal government has no minimu specifications for GAWR or GVWR. Certainly, this agency does not specify minimum weight ratings. Our only requirement is that the GAWR and GVWR be appropriate for the size and weight of a vehicle taking into consideration the type of equipment installed on it. From the information that you have provided us, we cannot say that the vehicle in question would or would not comply with that requirement. It is the responsibility of the vehicle manufacturer to certify that its vehicles comply with the Federal safety standards. No school bus manufacturer can sell you a school bus that they know will not comply with the requirements.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3319OpenMr. Dennis Newton, School Pupil Transportation, Kansas Department of Transportation, State Office Building, Topeka, KS 66612; Mr. Dennis Newton School Pupil Transportation Kansas Department of Transportation State Office Building Topeka KS 66612; Dear Mr. Newton: This responds to your June 2, 1980, letter asking whether a school bu that is to be sold to a school district in your State will meet the Federal minimum requirements applicable to gross axle weight ratings (GAWR) and gross vehicle weight ratings (GVWR).; To the best of my knowledge, the Federal government has no minimu specifications for GAWR or GVWR. Certainly, this agency does not specify minimum weight ratings. Our only requirement is that the GAWR and GVWR be appropriate for the size and weight of a vehicle taking into consideration the type of equipment installed on it. From the information that you have provided us, we cannot say that the vehicle in question would or would not comply with that requirement. It is the responsibility of the vehicle manufacturer to certify that its vehicles comply with the Federal safety standards. No school bus manufacturer can sell you a school bus that they know will not comply with the requirements.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3540OpenMr. M. W. Urban, Sure-View, Inc., 1337 N. Meridan Street, Wichita, KA 67203; Mr. M. W. Urban Sure-View Inc. 1337 N. Meridan Street Wichita KA 67203; Dear Mr. Urban: This responds to your letter of February 8, 1982, concerning complianc with Federal Motor Vehicle Safety Standards, in particular compliance with Safety Standard No. 111, *Rearview Mirrors*.; You are correct that section 102(2) of the National Traffic and Moto Vehicle Safety Act (15 U.S.C. 1392(2)) defines, in part, a motor vehicle safety standard as 'a minimum standard for motor vehicle performance....' Thus, each of the agency's safety standards sets a minimum level of performance which must be met by every manufacturer. Manufacturers are free to utilize designs that exceeds the minimum level of performance set by a standard as long as their products still comply with the standard. Thus, in the case of schoolbus rearview mirrors, a manufacturer must at least comply with the requirements of section 9.1 of Standard No. 111 regarding mirror size, and may voluntarily provide a mirror of a larger size. As explained in the enclosed letter, the Vehicle Safety Act authorizes the agency to regulate aspect of design, such as mirror size.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2251OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to Blue Bird Body Company's March 15, 1976, request fo confirmation that calculation of the material tensile strength of body panels under S6.2(a) of Standard No. 221, *School Bus Body Joint Strength*, is based on the minimum thickness permitted by American Society for Testing and Materials (ASTM) Standard 525 for the thickness specified in ordering the material. This response also reflects the April 1, 1976, meeting held between Blue Bird representatives and National Highway Traffic Safety Administration (NHTSA) personnel at Department of Transportation headquarters.; Under ASTM standards, the thickness of listed materials is permitted t vary from the specified or 'nominal' thickness by a small amount. If the thickness tolerance of a material is specified by the ASTM, the NHTSA bases its determination of thickness on the 'minimum thickness' specified for that material in the 1973 edition of the Annual Book of ASTM Standards. If the thickness tolerance of a material is not specified by the ASTM, the NHTSA uses the minimum thickness permitted by the school bus manufacturer's material specification.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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ID: aiam5187OpenMs. Laura J. Platter 6662 Mohawk Court Columbia, MD 21046; Ms. Laura J. Platter 6662 Mohawk Court Columbia MD 21046; "Dear Ms. Platter: This responds to your letter to Senator Barbar Mikulski about the Federal government's classification of minivans for safety purposes. You were concerned that classifying minivans as trucks rather than passenger vehicles would permit these vehicles to be equipped with fewer safety features. Congress has authorized this agency, the National Highway Traffic Safety Administration (NHTSA), to issue Federal motor vehicle safety standards that are applicable to new motor vehicles and items of motor vehicle equipment. In the last few years, NHTSA has extended nearly all the passenger car safety standards to cover light trucks and multipurpose passenger vehicles (MPVs). (Minivans are typically considered to be MPVs under our safety standards.) The only significant safety requirement for passenger cars that the agency has not extended to light trucks and MPVs is dynamic side impact protection. This is a new requirement that is being phased in for passenger cars beginning this September. NHTSA is currently in rulemaking to consider whether the dynamic side impact protection requirements should be extended to light trucks and MPV's, and published an advance notice of proposed rulemaking on this subject in June 1992. I hope this information is helpful to you. Sincerely, Howard M. Smolkin Acting Administrator cc: The Honorable Barbara A. Mikulski"; |
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ID: aiam2271OpenMr. Roger E. Stange, President, Norton Triumph Corporation, P.O. Box 275, Duarte, California 91010; Mr. Roger E. Stange President Norton Triumph Corporation P.O. Box 275 Duarte California 91010; Dear Mr. Stange: This is in reply to your letter of April 1, 1976, which requests a interpretation of Motor Vehicle Safety Standard No. 123 as it applies to a motor-driven cycle that your company intends to import.; "The speedometer on this machine displays both minor numerals and mino graduations at 5 mph intervals. Paragraph S5.2.3 and Column 3 of Table 3 of Standard No. 123 require that, if a motorcycle is equipped with a speedometer, 'Major graduations and numerals shall appear at 10 mph intervals, minor graduations at 5 mph intervals.' S5.2.3 also states that the abbreviations used in Column 2 and 3 are j minimum requirements and 'appropriate word may be spelled in full.' It is your interpretation that 'if the abbreviations used in Column 3 are minimum requirements ... the speedometer in question meets the minimum requirements and is therefore in conformity with the standard.'"; The 'abbreviations' only refer to words and not to numerals o graduations. However, since there is no specific prohibition against providing minor numerals at the minor graduations, we have concluded that Standard No. 123 allows a motorcycle manufacturer to furnish a speedometer with them if he so chooses.; Yours truly, Stephen P. wood, Assistant Chief Counsel |
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ID: aiam3902OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Dept., Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of January 18, 1985, to Mr. Vinson o this office asking for three interpretations of Motor Vehicle Safety Standard No. 108 with respect to motorcycle lighting.; Your first question is about the location of rear turn signals. Tabl IV of Standard No. 108 requires that rear turn signal lamps on motorcycles have a minimum horizontal separation distance 'centerline to centerline' of 9 inches. You have asked whether this may be interpreted as filament center to filament center., The answer is no. The phrase means the distance from the geometric center of one lamp to the geometric center of the other.; Your second questions concerns the permissibility of an arrangement o lamps on the rear of a motorcycle. There would be a two-compartment combination stop/tail lamp on the vehicle centerline with separate combination lamps below it on either side of the centerline. The distance between filament centers of the separate lamps would be a maximum 16 inches, and there would be the same distance between the filament centers of each separate lamp and the compartment above it belonging to the two- compartment lamp. You have asked whether this is permissible if the minimum design candlepower complies with requirements for three lighted sections in SAE J585e and SAE J586c, and the effective projected luminous lens area of each compartment or lamp is at least 3 1/2 square inches. This arrangement, though unusual, appears to be acceptable. SAE Standard J586c *Stop Lamps* and SAE J585e *Tail Lamps* state that if multiple compartment or multiple lamps are used, and the distance between filament centers does not exceed 16 inches for three compartment or lamp arrangements, the combination of the compartments or lamps must be used to meet the photometric requirements for the corresponding number of lighted sections. Your design has four lighted sections, where as the SAE Tables provide values for only three. In our opinion, your design would be acceptable provided that each of the four compartments meets the minimum value specified for test points in a section when there are three lighted sections.; Your final question concerns a combination stop/taillamp of fou sections, two each on either side of the vertical centerline. Though no distance is given for the filament centers, they appear to be closer than 16 inches. You have asked if this design is permissible provided it meets the requirements for three lighted sections, and the effective projected luminous lens area of each compartment is not less than 3 1/2 square inches. The answer is yes, this is acceptable provided that each of the four compartments meets the minimum value specified for test points in a section when there are three lighted sections.; 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.