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: aiam4786OpenMr. Gerald F. Vinci Sun Refining and Marketing Company Tenn Penn Center 1801 Market St. Philadelphia, PA 19103-1699; Mr. Gerald F. Vinci Sun Refining and Marketing Company Tenn Penn Center 1801 Market St. Philadelphia PA 19103-1699; "Dear Mr. Vinci: This responds to your August 14, 1990 letter an telephone calls about your plans to convert the fuel system on a vehicle from gasoline to propane. You said your company ('Sun Refining') would like to purchase a new vehicle and convert it for purposes of your own research, and will not be reselling the vehicle. You ask about the requirements that would apply to the conversion. We do not have any requirements that would apply to the conversion if the conversion is made by Sun itself. The National Traffic and Motor Vehicle Safety Act and NHTSA's regulations generally do not apply to a vehicle after the vehicle is sold to a consumer (e.g., Sun) for purposes other than resale. Although the Act prohibits certain entities from tampering with or removing federally required safety features, the prohibition does not apply to modifications by a vehicle owner to his or her own vehicle. However, in the event you have the conversion done by a party other than your company, Federal law may apply. Section 108(a)(2)(A) of the Safety Act prohibits vehicle manufacturers, distributors, dealers and repair businesses from knowingly rendering inoperative federally required safety features when modifying a vehicle. I have enclosed an information sheet that discusses the application of 108(a)(2)(A) to fuel system conversions. NHTSA wishes to learn more about the safety of propane fuel systems and is considering a public announcement seeking information on various safety issues. We would, therefore, be interested in the results of your research when they're completed. Even though your conversion would not be covered by the FMVSS's, we suggest you consult State law to see if the State has requirements for propane vehicles. In addition, other Federal agencies may have regulations for your vehicle. If your vehicle would be a commercial vehicle, the regulations of the Federal Highway Administration (FHWA) may apply. I have forwarded a copy of your letter to FHWA for their reply. You might also contact the Environmental Protection Agency (EPA) for information about the conversion. EPA's general telephone number is (202) 382-2090. I hope this information is helpful. Please contact us if you have further questions. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam2784OpenMr. Karsten J. Vieg, Governor's Representative for Highway Safety, Illinois Department of Transportation, 2300 South Dirksen Parkway, Springfield, IL 62764; Mr. Karsten J. Vieg Governor's Representative for Highway Safety Illinois Department of Transportation 2300 South Dirksen Parkway Springfield IL 62764; Dear Mr. Vieg: This is in reply to your letter of September 22, 1977, to th Administrator asking whether an Illinois standard applicable to school bus lighting is neither preempted by nor violates Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*.; Paragraph S4.1.4(b) (ii) of Standard No. 108 requires that: '>>>The [school bus signal lamp] system shall be wired so that th amber signal lamps are activated only by manual or foot operation and, if activated, are automatically deactivated and the red signal lamps automatically activated when the bus entrance door is opened.'<<<; Under the Illinois requirement (4.2.18.2) the amber signal lamps appea to be activated only by manual or foot control (4.2.18.2(d)), and are automatically deactivated when the bus entrance door is opened (4.2.18.2(e) and (f)). The red signal lamps are activated before the bus entrance door is opened (4.2.18.2(e)) and remain activated when the door is opened (4.2.18.2(f)). Thus, these portions of the Illinois requirement comply with Standard No. 108.; As for the remaining portions of 4.2.18.2, they dictate sequentia operational requirements of the 8-lamp system and stop arm (an item of equipment not required by Standard No. 108). To accomplish this operation, 4.2.18.2 requires that 'A separate circuit breaker and a master switch shall be provided for this signal system.' You have asked whether this is preempted by Standard No. 108.; The aspect of performance involved here is that of wiring requirement for school bus warning lamps. Standard No. 108 specifies the manner in which these lamps shall operate but it is silent as to the ways this performance shall be achieved. Therefore Illinois is not preempted from requiring a separate circuit breaker and master cylinder in school bus lighting systems, a specification which is one of good engineering practice and probably used as a matter of course by most school bus manufacturers.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2781OpenF. W. Flowers, Jr., General Engines Co., Inc., Interstate 295, Thorofare, NJ 08086; F. W. Flowers Jr. General Engines Co. Inc. Interstate 295 Thorofare NJ 08086; Dear Mr. Flowers: This responds to your January 13, 1978, letter asking whether prior t September of 1976, the National Highway Traffic Safety Administration (NHTSA) required the GAWR determination to be based upon an 'unrestricted' speed of 60 miles per hour.; The NHTSA requires that a vehicle's GAWR be based upon an unqualifie speed of 60 miles per hour. This GAWR computation is then inserted on a vehicle's certification plate by the manufacturer to inform users of the safe GAWR. However, it is permissible to then list at the bottom of a certification plate different GAWR's based upon reduced speeds. If you intended one of your vehicles to operate under a reduced speed with a higher GAWR, you should have marked the correct GAWR on the certification label computed at 60 miles per hour and listed the higher GAWR's for the reduced speeds at the bottom of the plate.; The 1976 amendment to which you refer, Standard No. 120, continues t require the same approach to GAWR as has been the agency's practice for many years. The only difference incorporated by the 1976 amendment is that those vehicles that are unable to attain speeds of 50 miles per hour in 2 miles need not base their determination on the 60 miles per hour figure. These vehicles may compute their GAWR's at a reduced speed. Nonetheless, they are still permitted to list at the bottom of the certification plate higher GAWR's for further reduced speeds.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4104OpenRobert R. Clark, Esq., Tabbert & Capehart, One Indiana Square, Suite 1500, Indianapolis, IN 46204; Robert R. Clark Esq. Tabbert & Capehart One Indiana Square Suite 1500 Indianapolis IN 46204; Dear Mr. Clark: This responds to your letter dated October 21, 1985, inquiring abou the certification responsibilities under federal law of your client, a new car dealer. You stated in your letter that your client plans to convert new automobiles into limousines. These limousines would then be sold wholesale to dealers.; The relevant federal statute is the National Traffic and Motor Vehicl Safety Act of 1966, as amended (15 U.S.C. 1391 *et seq*.). Under section 103 of the Act, this agency issues Federal motor vehicle safety standards and regulations applying to motor vehicles and their equipment.; As we understand the facts stated in your letter, the automobiles wil be completed by the original manufacturer who will certify that they meet all applicable Federal motor vehicle safety standards. Your client plans to alter the automobiles prior to their first purchase for purposes other than resale.; Your client's plan to convert automobiles would make him an alterer subject to the requirements of 49 CFR Part 567.7, *Certification*. An alterer is a person who alters a previously certified vehicle by means other than the addition, substitution, or removal of readily attachable components or minor finishing operations, or in such a manner that the vehicle's stated weight ratings are no longer valid. If the alteration is performed before the first purchase of the vehicle for purposes other than resale, the alterer must supplement the certification label by affixing an additional label stating that the vehicle as altered conforms to all applicable Federal motor vehicle safety standards and containing the firm or individual name of the alterer.; An alterer is also considered a manufacturer for the purposes o notification and recall for defects or noncompliance under the Act and is subject to the requirements of 49 CFR Part 573, *Defect and Noncompliance Reports*.; In addition, please note that your client should take care in makin the conversions not harm the vehicles' safety features. Under section 108 of the Act, a manufacturer, distributor, dealer, or motor vehicle repair business must not knowingly render inoperative, in whole or in part, any device or element of design which is installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. Your client would be subject to this prohibition which applies both before and after the first purchase of a motor vehicle for purposes other than resale.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4100OpenRobert R. Clark, Esq., Tabbert & Capehart, One Indiana Square, Suite 1500, Indianapolis, IN 46204; Robert R. Clark Esq. Tabbert & Capehart One Indiana Square Suite 1500 Indianapolis IN 46204; Dear Mr. Clark: This responds to your letter dated October 21, 1985, inquiring abou the certification responsibilities under federal law of your client, a new car dealer. You stated in your letter that your client plans to convert new automobiles into limousines. These limousines would then be sold wholesale to dealers.; The relevant federal statute is the National Traffic and Motor Vehicl Safety Act of 1966, as amended (15 U.S.C. 1391 *et seq*.). Under section 103 of the Act, this agency issues Federal motor vehicle safety standards and regulations applying to motor vehicles and their equipment.; As we understand the facts stated in your letter, the automobiles wil be completed by the original manufacturer who will certify that they meet all applicable Federal motor vehicle safety standards. Your client plans to alter the automobiles prior to their first purchase for purposes other than resale.; Your client's plan to convert automobiles would make him an alterer subject to the requirements of 49 CFR Part 567.7, *Certification*. An alterer is a person who alters a previously certified vehicle by means other than the addition, substitution, or removal of readily attachable components or minor finishing operations, or in such a manner that the vehicle's stated weight ratings are no longer valid. If the alteration is performed before the first purchase of the vehicle for purposes other than resale, the alterer must supplement the certification label by affixing an additional label stating that the vehicle as altered conforms to all applicable Federal motor vehicle safety standards and containing the firm or individual name of the alterer.; An alterer is also considered a manufacturer for the purposes o notification and recall for defects or noncompliance under the Act and is subject to the requirements of 49 CFR Part 573, *Defect and Noncompliance Reports*.; In addition, please note that your client should take care in makin the conversions not harm the vehicles' safety features. Under section 108 of the Act, a manufacturer, distributor, dealer, or motor vehicle repair business must not knowingly render inoperative, in whole or in part, any device or element of design which is installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. Your client would be subject to this prohibition which applies both before and after the first purchase of a motor vehicle for purposes other than resale.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4054OpenMr. Robert R. Gregg, Metzeler Motorcycle Tire, Agent Gregg, Inc., 144 Railroad Avenue, Suite 215, Edmonds, WA 98020; Mr. Robert R. Gregg Metzeler Motorcycle Tire Agent Gregg Inc. 144 Railroad Avenue Suite 215 Edmonds WA 98020; Dear Mr. Gregg: This responds to your letter to Steve Kratzke of my staff, seeking a interpretation of Standard No. 119, *New Pneumatic Tires for Motor Vehicles Other Than Passenger Cars (49 CFR Part 571.119). Specifically, you asked if a motorcycle tire could have its maximum load capacity labeled on the sidewall as follows:; >>>At 60 MPH Max load _____lbs. at _____ psi cold.<<< Such labeling would violate Standard No. 119, as explained below. Section S6.5 of Standard No. 119 requires that certain information b labeled on the sidewall of all tires to which the standard applies. Section S6.5(d) requires the maximum load rating and corresponding inflation pressure to appear on all motorcycle tires as follows:; >>>Max load _____lbs at _____psi cold.<<< No speed rating or restriction may be given in conjunction with th maximum load rating on the sidewall of the tire. That rating, as its name implies, is intended to alert consumers to the tire's *maximum* capabilities.; A manufacturer may label a speed restriction on its tires to aler consumers to the tire's maximum speed if that maximum is 55 miles per hour (mph) or less. Section S6.5(e) permits speed restrictions of 55 mph or less to be labeled on the sidewall of the tire as follows:; >>>Max Speed _____mph. << |
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ID: aiam4552OpenMr. Garry Gallagher Vice President Metzeler Motorcycle Tire 4520 107th SW Everett, WA 98204; Mr. Garry Gallagher Vice President Metzeler Motorcycle Tire 4520 107th SW Everett WA 98204; "Dear Mr. Gallagher: This responds to your letter seeking a interpretation of Standard No. 119, New Pneumatic Tires for Motor Vehicles Other Than Passenger Cars (49 CFR /571.119). More specifically, you asked whether the letter 'B' must appear as part of the size designation of a motorcycle tire if that tire is of bias belted construction. The answer to your question is no. As you noted in your letter, section S6.5 of Standard No. 119 sets forth the marking requirements for tires used on motor vehicles other than passenger cars, including tires for use on motorcycles. Subsection S6.5(c) states that each such tire shall be marked with 'The tire size designation as listed in the documents and publications designated in S5.1.' Section S5.1, in turn, specifies tire and rim matching information that must be provided to the public. Generally speaking, the size designation of a tire shows only the physical dimensions of that tire, not necessarily its construction. Thus, the common meaning of the term 'size designation' does not necessarily include an indication of the tire's construction type. Further, no provision of Standard No. 119 requires a tire's size designation to indicate the tire's construction type. The only reference in section S6.5 of Standard No. 119 to a tire's construction type is in subsection S6.5(i), which requires the word 'radial' to appear on the tire's sidewall if the tire is of radial construction. Therefore, in response to your question, Standard No. 119 does not require the letter 'B' to be included in the size designation of bias belted motorcycle tires. You noted that your company sometimes adds the letter 'B' to the size designation of these tires as an internal code. NHTSA has long said that manufacturers are free to include additional information on the sidewall of their tires, provided that the additional information does not obscure or confuse the meaning of the required information, or otherwise defeat the purpose of the required information. In this case, the addition of the letter 'B' to the size designation would not appear to confuse or obscure the meaning of the size designation. Hence, there would be no apparent violation of Standard No. 119 by including the letter 'B' in the size designation of bias belted motorcycle tires. If you have any further questions or need additional information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam1058OpenAlan S. Flink, Esq., 830 Hospital Trust Building, Providence, RI 02903; Alan S. Flink Esq. 830 Hospital Trust Building Providence RI 02903; Dear Mr. Flink: This is in response to your letter of March 7, 1973, concerning th Federal Odometer Disclosure Requirements, 49 CFR Part 580. Our replies to your numbered questions are as follows:; >>>1) The disclosure statement specified by section 408(a) of P.L 92-513 must contain the indicated mileage, regardless of whether the transferor knows the indicated mileage to be wrong. Subsections (1) and (2) of section 408(a) are not stated in the alternative. The statement of mileage specified in (1) is thus required by our regulation to be given upon each transfer. In addition, the statute provides that 'if the odometer reading is *known* to be different from the number of miles the vehicle has actually traveled,' the actual mileage shall be disclosed as unknown. (emphasis supplied) There are numerous commercial situations, such as repossessions, in which the party obtaining possession of the vehicle has had no prior control over the vehicle's operation. In such situations, the repossessing party should not state, upon resale, that the mileage is unknown unless he knows, or has a reasonable belief, that the odometer is wrong.; 2) We have no object to your including a space on the form to indicat mileage beyond the mechanical limits of the odometer.; 3) The phrase 'true mileage unknown' is not obligatory. If th transferor knows the indicated mileage is wrong, he must say so and must state, in substance, that the actual or true mileage is not known. There are only a few ways in which he can convey this thought accurately, but the regulation does not compel him to choose the phrase 'true mileage unknown.'; 4) Our reading of the Rhode Island law leaves us in doubt as to whethe it requires the true mileage to be entered on the form in the event the indicated mileage is wrong. Paragraph (2) of section 31-23.2-6 appears to have the same effect as section 408(a)(2) of P.L. 92-513. A statement of the actual mileage would not be compatible with the statement under Federal law that the true mileage is unknown, but we do not see that a transferor would be required under Rhode Island law to make such an incompatible statement.; 5) No. The State form may be used. 6) The date required is the date of transfer. The date of th disclosure statement will rarely be different, but if it is, the date of transfer should be used on the statement.; 7) Yes. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2232OpenMr. Lawrence MacEachern, Cal Light Co., 50 Oak Court, Walnut Creek, CA, 94596; Mr. Lawrence MacEachern Cal Light Co. 50 Oak Court Walnut Creek CA 94596; Dear Mr. MacEachern: In your latest letter, dated February 17, 1976, you asked 'Does th Federal motor vehicle safety standards allow the use of one half of an automobile headlight system on a motorcycle?'; There is no Federal prohibition against an owner modifying hi motorcycle to use any lighting configuration, though there may be State or municipal restrictions. The answer where a manufacturer is involved, however, depends upon the type of automobile headlamp system used. Motor Vehicle Safety Standard No. 108 requires a motorcycle to be equipped with a headlamp system conforming to SAE Standard J584, *Motorcycle and Motor Driven Cycle Headlamps*, April 1964. Two options allowed are use of a single 7 inch sealed beam unit, or of one 5 3/4 inch Type 1 and one 5 3/4 inch Type 2 sealed beam unit, provided these headlamps meet the requirements of SAE J579a, *Sealed Beam Headlamp Units for Motor Vehicles*, August 1965. Thus, 'one half' of a two-headlamp, or of a four-lamp circular lens passenger car headlighting system could be used on a motorcycle. But use of a system comprised of one Type 1A plus Type 2A (rectangular lens), is not currently permitted under Standard No. 108.; Since there is an equivalence of performance between rectangular an circular lens headlamp systems, if you wish to merchandise a two-lamp (Type 1A plus Type 2A) rectangular system for use on motorcycles, you may wish to submit an additional petition for an amendment of Standard No. 108.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3922OpenMr. John D. Dusenbury, Chief Counsel, United States Fleet Leasing, Inc., No. 2 Waters Park Drive, San Mateo, CA 94403; Mr. John D. Dusenbury Chief Counsel United States Fleet Leasing Inc. No. 2 Waters Park Drive San Mateo CA 94403; Dear Mr. Dusenbury: This is in response to your request of February 7, 1985, for a list o those states which have a sufficient amount of odometer disclosure information on the certificate of title so that a separate odometer disclosure statement is not necessary.; Please be advised that no such list is maintained by the Agency. Th applicable Federal regulation, 49 CFR Part 580 provides that State titles or other ownership documents may be used as substitutes for the Federal odometer disclosure statement if they contain essentially the same information required by paragraphs (a), (b), (c) and (e) of section 580.4. It is only if the information varies in any way from that required for the Federal form that the State must obtain the approval of this Agency.; Pursuant to your request, I have reviewed State titles contained wit *The Original Peck's Title Book*. This book published by Stephens-Peck, Inc. is revised periodically and supplemented as changes in state title laws occur. To date, the title documents of the following states may be used in lieu of a separate odometer disclosure form:; >>>Michigan, Minnesota, North Carolina, North Dakota, Ohio, Soug Dakota, Virginia<<<; I must qualify this list, however. With regard to the Michigan an Minnesota letters, it is only the initial assignment which meets all disclosure requirements. Reassignments by a licensed dealer do not, as there is no space for the purchaser's signature. The National Highway Traffic Safety Administration considers the signature to be essential because it is an acknowledgement that the purchaser is aware of the mileage. The signature prevents the purchaser from later alleging that he was not informed of the mileage or that the mileage was different from that appearing on the table.; When vehicles are transferred in North Dakota, Ohio or Virginia, th title can be used in lieu of a separate odometer disclosure statement only if the purchaser completes all information concerning the application for title. Unless the application is completed, the title will not include the buyer's signature.; In transferring vehicles titled in all the states listed above, Unite States Fleet Leasing, Inc. must retain a photostat of the title for its records. In all other instances, the company must issue a odometer disclosure statement and retain a photostat, carbon or other facsimile copy.; If I can be of further assistance, do not hesitate to contact me. Sincerely, Jeffrey R. Miller, 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.