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: aiam3045OpenMr. R. G. Clifton, Manager, Tyre Legislation, Dunlop Limited, Tyre Technical Division, Fort Dunlop, Birmingham, England B24 9QT; Mr. R. G. Clifton Manager Tyre Legislation Dunlop Limited Tyre Technical Division Fort Dunlop Birmingham England B24 9QT; Dear Mr. Clifton: This is in response to your letter of May 8, 1979, requesting a exemption from the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104), Federal motor vehicle safety standard 109 (49 CFR 571.109), and the tire identification and recordkeeping requirements of Part 574 (49 CFR Part 574) for several lines of 'antique' tires.; Dunlop's petition for exemption does not qualify as a petition fo temporary exemption from motor vehicle safety standards under Part 555 (49 CFR Part 555), since that part applies only to manufacturers of motor vehicles. However, the regulations you refer to apply only to tires for use on vehicles manufactured after 1948 (49 CFR 575.104(c)), (sic)49 CFR 571.109, S2, 49 CFR 574.4), and therefore, many of the tires listed in your letter are not within the scope of these regulations. Also, the National Highway Traffic Safety Administration plans to issue in the near future a notice of proposed rulemaking to exclude limited production tires from the application of the UTQG Standards, regardless of the tire's intended use.; You also asked that some form of labeling system be adopted for tire which are not required to be graded under the UTQG regulation, to facilitate processing of such tires by United States customs authorities. Regulations governing importation of motor vehicle equipment (19 CFR 12.80) only require compliance with applicable Federal motor vehicle safety standards, as set forth in 49 CFR Part 571. Any tire marked with the DOT symbol as required by Standard No. 109 (49 CFR 571.109, S4.3.1) or Standard No. 119 (49 CFR 571.119, S6.5(a)), as applicable, or which is not required to comply with such standards, will be processed expeditiously by customs authorities, and the question of compliance with the UTQG regulation should not arise. While NHTSA does not consider it necessary to impose a labeling system for tires excluded from the UTQG Standard, the agency has no objection to voluntary labeling by manufacturers or importers.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3044OpenMr. R. G. Clifton, Manager, Tyre Legislation, Dunlop Limited, Tyre Technical Division, Fort Dunlop, Birmingham, England B24 9QT; Mr. R. G. Clifton Manager Tyre Legislation Dunlop Limited Tyre Technical Division Fort Dunlop Birmingham England B24 9QT; Dear Mr. Clifton: This is in response to your letter of May 8, 1979, requesting a exemption from the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104), Federal motor vehicle safety standard 109 (49 CFR 571.109), and the tire identification and recordkeeping requirements of Part 574 (49 CFR Part 574) for several lines of 'antique' tires.; Dunlop's petition for exemption does not qualify as a petition fo temporary exemption from motor vehicle safety standards under Part 555 (49 CFR Part 555), since that part applies only to manufacturers of motor vehicles. However, the regulations you refer to apply only to tires for use on vehicles manufactured after 1948 (49 CFR 575.104(c)), (sic)49 CFR 571.109, S2, 49 CFR 574.4), and therefore, many of the tires listed in your letter are not within the scope of these regulations. Also, the National Highway Traffic Safety Administration plans to issue in the near future a notice of proposed rulemaking to exclude limited production tires from the application of the UTQG Standards, regardless of the tire's intended use.; You also asked that some form of labeling system be adopted for tire which are not required to be graded under the UTQG regulation, to facilitate processing of such tires by United States customs authorities. Regulations governing importation of motor vehicle equipment (19 CFR 12.80) only require compliance with applicable Federal motor vehicle safety standards, as set forth in 49 CFR Part 571. Any tire marked with the DOT symbol as required by Standard No. 109 (49 CFR 571.109, S4.3.1) or Standard No. 119 (49 CFR 571.119, S6.5(a)), as applicable, or which is not required to comply with such standards, will be processed expeditiously by customs authorities, and the question of compliance with the UTQG regulation should not arise. While NHTSA does not consider it necessary to impose a labeling system for tires excluded from the UTQG Standard, the agency has no objection to voluntary labeling by manufacturers or importers.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3059OpenMr. Peter Bigwood, Chief Engineer, Ontario Bus Industries Inc., 5395 Maingate Drive, Mississauga, Ontario; Mr. Peter Bigwood Chief Engineer Ontario Bus Industries Inc. 5395 Maingate Drive Mississauga Ontario; Dear Mr. Bigwood: This responds to your July 16, 1979, letter asking two questions abou the test procedures of Standard No. 217, *Bus Window Retention*, as they apply to buses you manufacture.; First, you ask whether side service doors can be counted in determinin the proper amount of bus emergency exits as required by the standard. As long as side service doors comply with all requirements applicable to emergency doors, they can be considered emergency exits for purposes of compliance with the standard.; Your second question asks whether glazing in a door is tested fo window retention, and if so, whether it is tested while the door is installed in a bus. The answer to both parts of this question is yes. All bus glazing, that is of the minimum size specified in the standard, must comply with the window retention requirement. The intent of the window retention requirement is to prevent openings in buses that might result in the ejection of occupants from the vehicle during an accident. In order for this requirement to have meaning, the glazing must be tested as it is installed in the vehicle to ensure the integrity of both the glazing and its surrounding structure. This means that glazing in vehicle doors is tested while the door is in the normal closed condition. If the door opens during the test, the vehicle would not be in compliance with the requirements.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2799OpenMr. Joe Purko, Director, Bureau of Transportation, Room 4201, City Hall, Los Angeles, CA 90012; Mr. Joe Purko Director Bureau of Transportation Room 4201 City Hall Los Angeles CA 90012; Dear Mr. Purko: This responds to your March 10, 1978, question whether Standard No 121, *Air Brake Systems*, applies to a device that automatically applies to (sic) vehicle's service brakes when a sensing bumper mounted at the rear of the vehicle is tripped by contact with an object during backing maneuver. For purposes of your question, I assume that the vehicle, whether new or used, has been certified to comply with Standard No. 121 prior to installation of the device.; The answer to your question is no. Paragraph S3 (Applicability) o Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some specified exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the braking actuator you describe. The vehicle must, of course, conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale.; After the first retail sale, S108(a)(2)(A) of the National Traffic an Motor Vehicle Safety Act (the Act) (15 U.S.C. S1397(a)(2)(A)) prohibits, with one exception, manufacturers, distributors, dealers, and repair businesses from knowingly rendering inoperative devices or elements of design installed in satisfaction on a safety standard such as Standard No. 121.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3476OpenMr. Morris Wiant, Coleman Company, Inc., 250 North St. Francis, Wichita, KS 67202; Mr. Morris Wiant Coleman Company Inc. 250 North St. Francis Wichita KS 67202; Dear Mr. Wiant: This is in response to your telephone conversation of September 17 wit Roger Fairchild of this office, in which you requested written confirmation that your company's vehicle identification number system as described in your June 8 letter to this agency complies with Federal Motor Vehicle Safety Standard No. 115.; The National Highway Traffic Safety Administration does not giv advance approval of a manufacturer's compliance with motor vehicle safety standards or regulations as it is the manufacturer's responsibility under the National Traffic and Motor Vehicle Safety Act to ensure that its vehicles comply with the applicable safety standards. However, my office has reviewed your proposed system. Based on our understanding of the information which you have provided, your system apparently complies with Standard No. 115.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5596OpenMr. Isaias Rios Product Engineering Department Rines de Acero K-H, S.A. de C.V. Hidalgo No. 8 Esquina Plano Regulador Xocoyahualco, Tlalnepantla Estado de Mexico C.P. 54080 Mexico; Mr. Isaias Rios Product Engineering Department Rines de Acero K-H S.A. de C.V. Hidalgo No. 8 Esquina Plano Regulador Xocoyahualco Tlalnepantla Estado de Mexico C.P. 54080 Mexico; "Dear Mr. Rios: This responds to your letter of June 29, 1995, t Marvin Shaw of this office requesting information on obtaining a certification from the U.S. that the wheels you supply to automobile manufacturers in Mexico comply with Federal Motor Vehicle Safety Standard (FMVSS) Nos. 110 and 120. You explained in your letter and in telephone conversations with Walter Myers of this office that your company supplies steel and aluminum passenger car wheels to automobile manufacturers located in Mexico. You stated that Nissan Mexicana requires from you a certificate demonstrating compliance with FMVSS Nos. 110, Tire Selection and Rims, and 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars. Your letter asked how to obtain such a certification and for information on other responsible U.S. government agencies and approved test labs. On July 21, Mr. Myers telefaxed you copies of two interpretative letters previously issued by this office, one to Mr. Ralph Trimarchi dated February 11, 1985, and one to Mr. Jay D. Zeiler dated November 20, 1977. We explained in those letters that U.S. law requires motor vehicle and equipment manufacturers to self-certify their products and that the U.S. government does not test or certify products prior to first retail sale. Rather, this agency, the National Highway Traffic Safety Administration (NHTSA), randomly tests vehicles and equipment for compliance with the FMVSSs. Mr. Myers also telefaxed you copies of FMVSS Nos. 110 and 120 on July 24, 1995. We would like to advise you of another issue. 49 Code of Federal Regulations (CFR) Part 566 (copy enclosed) requires manufacturers of motor vehicle equipment to which an FMVSS applies (referred to in the regulation as 'covered equipment,' such as wheels) to submit its name, address, and a brief description of the items of equipment it manufactures to NHTSA. NHTSA requires that information from an equipment manufacturer even though the equipment manufacturer does not directly sell its products in the U.S. but supplies them to foreign vehicle manufacturers who sell their vehicles in the U.S. (see enclosed copy of NHTSA letter to Mr. K. Nakajima, dated January 6, 1972). Therefore, if your company has not already done so, please submit the information required by Part 566 to the Administrator of NHTSA within thirty days after receipt of this letter. No forms or prescribed format is required. A standard letter is sufficient. I hope this information is helpful to you. Should you have any further questions or need any additional information, please feel free to contact Mr. Myers at this address or by telephone (202) 366-2992 or telefax (202) 366-3820. Sincerely, John Womack Acting Chief Counsel Enclosures"; |
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ID: aiam2716OpenMr. Robert Kurre, Director of Engineering, Wayne Corporation, Industries Road, Richmond, IN 47374; Mr. Robert Kurre Director of Engineering Wayne Corporation Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your oral request to Roger Tilton of my staff for th reasons that the National Highway Traffic Safety Administration (NHTSA) exempted buses with gross vehicle weight ratings of 10,000 pounds or less from the requirements of Standard No. 221, *School Bus Body Joint Strength*.; As you know, the NHTSA promulgated the joint strength standard t prevent injuries resulting from the impact of children with the sharp protruding edges of body panel sheets that become unfastened in school bus accidents. This problem, according to the information available to the agency, was particularly acute with respect to large school buses. The agency has no similar data indicating that the joint severance problem is a major factor contributing to injuries in accidents involving smaller school buses. Accordingly, the agency exempted those vehicles from the requirements. Should the NHTSA discover in the future that such problems exist with respect to smaller buses, it would consider extending the requirements to them.; I am enclosing a copy of our last notice on Standard No. 221 that full outlines our reasons for exempting smaller school buses.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1708OpenMr. T. W. Lucas, Vehicle Safety Coordinator, Mack Trucks, Incorporated, P. O. Box 1791, Allentown, PA 18105; Mr. T. W. Lucas Vehicle Safety Coordinator Mack Trucks Incorporated P. O. Box 1791 Allentown PA 18105; Dear Mr. Lucas: This is in reference to your defect notification campaign (NHTSA No 74-0120) concerning some trucks with Rockwell FL-901 front axle assemblies with possibly defective steering arms.; The letter which you have sent to the owners of the subject vehicle does not completely meet the requirements of Part 577 (49 CFR), the Defect Notification regulation. Since your company is notifying the owners regarding a defect in certain Mack trucks, the second sentence of your letter should have stated that Mack Trucks, Inc., has determined that a defect exists in those vehicles. The reference to item of motor vehicle equipment in Part 577.4(b) only applies to campaigns being conducted by equipment manufacturers.; Your letter also does not give an estimate of the day by which dealer will be supplied with parts and instructions for correcting the defect as required by Part 577.4(e). Although it will not be necessary to renotify owners in this instance, it is expected that all future defect notifications fully comply with all applicable regulations. A copy of Part 577 is enclosed.; Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam1418OpenMr. Gary T. Rath, General Manager, Mobile Auto Glass of Iowa, Inc., 1600 Second Avenue, Des Moines, IA 50314; Mr. Gary T. Rath General Manager Mobile Auto Glass of Iowa Inc. 1600 Second Avenue Des Moines IA 50314; Dear Mr. Rath: Thank you for your letter of January 30, 1974, concerning requirement for replacement glazing material in trucks and buses.; Glazing materials for use in motor vehicles must comply with th requirements of Federal Motor Vehicle Safety Standard No. 205, Glazing Materials, which incorporates the American National Standards Institute Standard No. Z26.1-1966. Section S6 of Standard No. 205 specifies requirements for certification and marking.; Paragraph S6.4 and S6.5 of Standard No. 205 covers the specifi question you asked. If you cut a section of glass to which this standard applies, for use in a motor vehicle or camper, you are required to mark that glass in accordance with section 6 of Standard No. Z26.1-1966 and to certify that it complies with the standard in accordance with section 114 of the National Traffic and Motor Vehicle Safety Act.; I am enclosing a copy of Standard No. 205, Standard No. Z26.1-1966 an section 114 of the National Traffic and Motor Vehicle Safety Act. If I can be of further assistance, do not hesitate to contact me.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2108OpenMr. Claud Riggs, Mountain States Tire Dealers Association, 1230 Pontiac Street, Denver, CO 80220; Mr. Claud Riggs Mountain States Tire Dealers Association 1230 Pontiac Street Denver CO 80220; Dear Mr. Riggs: Please forgive the delay in responding to your letter of May 1, 1975 which included a list of information items you believe are required to appear on retreaded tires pursuant to Federal Motor Vehicle Safety Standard No. 117, *Retreaded Pneumatic Tires*.; With the following qualifications, your list is correct: >>>1. The tire must be labeled with the symbol 'DOT' followed by th letter 'R', and other information required by 49 CFR Part 574.5, *Tire Identification and Recordkeeping*, as a certification that the tire complies with Standard No. 117. This requirement is distinct from and in addition to the requirement that the casing retain the 'DOT' symbol from its original manufacture.; 2. The words 'bias/belted' are not required, because the actual numbe of plies in the sidewall and, if different, in the tread area, are now required to appear.; 3. Tube-type and tubeless tires must be labeled with the specific word 'tube-type' and 'tubeless', respectively.; 4. The items listed in your third group may appear on a paper labe only if that label is not easily removable.<<<; For you convenience, I have enclosed a copy of Standard No. 117. Yours truly, Richard B. Dyson, Assistant 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.