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: aiam0898OpenMr. Donald P. Koch, Insurance Rate Analyst, Division of Insurance, Department of Commerce, State of Alaska, Pouch D - Juneau 99801; Mr. Donald P. Koch Insurance Rate Analyst Division of Insurance Department of Commerce State of Alaska Pouch D - Juneau 99801; Dear Mr. Koch: This is in reply to your letter of October 4, 1972, concerning th possible misuse by automobile insurers of vehicle identification numbers (VIN's) which would be available to them under a proposed amendment to NHTSA 'Defect Reports' regulations (49 CFR Part 573). You believe that the availability of such numbers could be the basis for some companies to refuse to write or to cancel insurance, and suggest that we notify state insurance commissioners of that possibility.; We appreciate your concern over the possible misuse of informatio obtained as a result of NHTSA regulations. However, we have no evidence at this time that such practices are occurring, and we believe it inappropriate, without evidence, to take action which raises the implication of impropriety on the part of the insurance industry. Of course, if we find evidence of misuse of information obtained as a result of NHTSA regulations, we will take steps to remedy the situation.; Your letter and our response have been placed in Docket 69-31, whic concerns the reporting of VIN's. We appreciate your writing to us regarding this matter.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam4588OpenMr. Richard L. Story, Sr. 34855 Annapolis Ave. Wayne, MI 48184-2133; Mr. Richard L. Story Sr. 34855 Annapolis Ave. Wayne MI 48184-2133; "Dear Mr. Story: This responds to your letter asking whethe manufacturers are required to install rear seat lap/shoulder belts in cars originally equipped with rear seat lap belts at no additional cost to the consumer. The answer to this question is no. The lap belts that are installed in the rear seat of your car are effective in reducing the risk of death and injury in a crash. Based on this agency's analysis of a number of crash data files, we estimate that rear seat lap belts saved about 100 lives and prevented over 1500 serious injuries in 1987 alone. These figures would have been substantially higher if more rear seat occupants used their lap belts. In fact, if everyone had worn their rear seat lap belts each time they rode, those belts would have saved about 660 lives and prevented more than 10,000 serious injuries in 1987 alone. Even though lap belts have been proven to be effective in reducing the risk of death and injury in a crash, we agree that properly designed lap and shoulder belts have the potential to offer even greater crash protection than lap belts alone. For this reason, we have proposed to require that all new passenger cars sold in the United States be equipped with rear seat lap and shoulder belts beginning in the 1990 model year. For cars made in earlier model years, we have actively sought the car manufacturers' cooperation in providing retrofit kits to interested consumers. You indicated in your letter that Ford offers a rear seat lap and shoulder belt retrofit kit for your car, the 1988 Thunderbird. We encourage consumers to consider having rear seat lap and shoulder belts fitted into their cars when manufacturers have made a retrofit kit available for the car, because of the additional crash protection afforded to rear seat passengers. However, NHTSA has no authority to require manufacturers to provide these retrofit kits and installation free of charge to the consumer. Thus, the individual consumer who desires the added protection of lap and shoulder belts in the rear seat will have to pay for that additional protection. I hope this information is helpful. If you have any further questions or need additional information on this subject, please let me know. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam1270OpenMr. R.A.C. Dandy, British Standards Institution, Hemel Hempstead Centre, Maylands Avenue, Hemel Hempstead, Herts HP2 4SQ; Mr. R.A.C. Dandy British Standards Institution Hemel Hempstead Centre Maylands Avenue Hemel Hempstead Herts HP2 4SQ; Dear Mr. Dandy: This is in reply to your letter of August 20, 1973, which we receive September 17, 1973, concerning the application of Standard No. 302, 'Flammability of Interior Materials,' to seat belt assemblies.; You ask whether components of the seat belt assembly such as plasti buckle covers must meet the requirements of the standard as well as the belt itself. Standard No. 302 applies to all enumerated interior materials, not just 'textile materials or sheet materials.' Since plastic buckle covers are considered part of the seat belt, they must meet the standard's requirements.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4422OpenLawrence C. Bourbeau, Jr., Esq. Assistant General Counsel Fruehauf Corporation, Law Department 10900 Harper Avenue P.O. Box 238 Detroit, MI 48232; Lawrence C. Bourbeau Jr. Esq. Assistant General Counsel Fruehauf Corporation Law Department 10900 Harper Avenue P.O. Box 238 Detroit MI 48232; Dear Mr. Bourbeau: This letter responds to your earlier inquiry wher you ask whether NHTSA would object to your Company's changing 'its model year designation from September 1 to July 1.' I apoligize for the delay in responding. Standard 115, Vehicle Identification Number- Basic Requirements, directs vehicle manufacturers to place a discrete identifying number (VIN) on each vehicle. Title 49 CFR Part 565, VIN- Content Requirements, states that a VIN must include a character indicating the manufacturer's designated model year. Neither Standard 115 nor Part 565 prohibits your company from changing the model year in the manner you suggest. Therefore, such a change does not violate our regulations. We note that this change apparently concerns model year as a marketing concept. The Federal Trade Commission has published guidelines concerning model year as a commercial concept, and you may wish to contact the Commission for whatever assistance it may provide. I hope you find this information helpful. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1620OpenMr. Francois Louis, Manager, Technical Standards Dept., Renault, Inc., 100 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Francois Louis Manager Technical Standards Dept. Renault Inc. 100 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Louis:#This is in response to your letter of September 13 1974, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 101.#You ask confirmation that your proposed vertically lettered identification for windshield wiper and hazard warning switches will meet the requirement of Standard No. 101, S4.2.1, that the identification 'shall appear to the operator in an upright position.'#Both horizontally and vertically lettered identifications are acceptable, as long as their appearance is upright. We have no objection to your use of the proposed designations.#Yours truly, Richard B. Dyson, Acting Chief Counsel; |
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ID: aiam0932OpenMr. William J. Henrick,Assistant Counsel, The General Tire & Rubber Company, One General Street, Akron, Ohio 44329; Mr. William J. Henrick Assistant Counsel The General Tire & Rubber Company One General Street Akron Ohio 44329; Dear Mr. Henrick: This is in reply to your letter of November 8, 1972, inquiring whethe new casings, to which tread is later added, are considered to be 'tires' under the National Traffic and Motor Vehicle Safety Act. The NHTSA has taken the position that such casings are not tires until after the tread has been added, and the casings are not required to be certified as conforming to applicable standard until that occurs. Consequently, such casings may be imported without prior certification.; You also ask how best to inform Customs of our position, to avoi possible importation problems. We suggest you write to Mr. P.K. McCarthy, Chief, Restrictive Merchandise Branch, U.S. Bureau of Customs, Room 704c, 1145 19th Street, N.W., Washington, D.C. 20226, advising him of our opinion, and ask him to acknowledge this interpretation. You might also take steps to ensure that this information is relayed to the local customs officials at those ports of entry where the casings will be imported. If you need further assistance in this matter, please let me know.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3133OpenMr. R. W. Hildebrandt, Group Director-Engineering, Bendix Corporation, 901 Cleveland Street, Elyria, OH 44035; Mr. R. W. Hildebrandt Group Director-Engineering Bendix Corporation 901 Cleveland Street Elyria OH 44035; Dear Mr. Hildebrandt: This responds to your September 20, 1979, letter asking the Nationa Highway Traffic Safety Administration (NHTSA) to give you written confirmation that your tandem axle trailer brake system complies with Standard No. 121, *Air Brake Systems*.; The NHTSA does not provide advance determinations of compliance wit the agency's safety standards. It is the manufacturer's responsibility to test for and certify the compliance of its vehicles or equipment. The agency cannot always tell by diagrams and word descriptions whether a system will or will not comply with applicable safety standards. Compliance of a braking system, such as yours, can only be determined when tested on a completed vehicle.; Our technical staff has reviewed the diagrams and the letter that yo submitted. In their opinion, your system appears to comply with the requirements of the standard. However, this is merely an opinion based upon your submission and does not bind the agency in any way should your device fail any compliance tests conducted by the agency.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3563OpenMr. Edward H. Clapp, President, Transquip Industries, Inc., 1222 RepublicBank Oak Cliff, Dallas, TX 75208; Mr. Edward H. Clapp President Transquip Industries Inc. 1222 RepublicBank Oak Cliff Dallas TX 75208; Dear Mr. Clapp:#This responds to your recent letter asking whethe Federal regulations allow a brake hose to be used as a dual purpose hose for both the service brakes and the emergency brake.#Standard No. 121, *Air Brake Systems*, does not preclude the use of common components in parking, emergency, and service air brake systems. Accordingly, nothing would prevent you from using a common hose in those systems. However, the common component would have to comply with the requirements for each system. This means that a failure of the hose would always be treated as a failure in the parking, emergency and service brake systems. Applying this to the standard in section S5.2.1.1, it would be necessary for the parking brakes to be capable of being released with a failure of the common hose at any time. If your system cannot perform in this manner, which it appears it cannot, it could not comply with the safety standard.#Our engineering staff has reviewed your brake system very carefully over the past years. It appears that your system can be properly plumbed in a manner that it would seem to comply with the requirements. You have continued to seek slightly less expensive methods to plumb your system. In our opinion, these methods would not be capable of complying with the standard. We cannot see how your system can comply with the standard without traditional plumbing that is being used by many brake manufacturers today. Accordingly, we suggest that you concentrate your efforts on constructing your system in that manner.#Sincerely, Frank Berndt, Chief Counsel; |
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ID: aiam3099OpenMr. Harry W. Reynolds, Supervisor, Fleet Maintenance Division, DeKalb County School System Service Center, 1780 Montreal Road, Tucker, GA 30084; Mr. Harry W. Reynolds Supervisor Fleet Maintenance Division DeKalb County School System Service Center 1780 Montreal Road Tucker GA 30084; Dear Mr. Reynolds:This responds to your July 27, 1979, letter whic asked whether any Federal law or regulations would prohibit the DeKalb County School System from converting the gasoline fuel systems in its school buses to propane fuel or dual propane- gasoline fuel systems. You specified that you would like this question answered both with respect to school buses manufactured in accordance with Federal Motor Vehicle Safety Standard No. 301- 75 and with respect to school buses manufactured before that standard's effective date. You also asked which persons may perform the conversions. As explained below, the laws administered by the National Highway Traffic Safety Administration (NHTSA) neither prohibit such a conversion of a school bus, regardless of whether it was initially manufactured in compliance with Safety Standard No. 301-75, nor specify which persons may perform such conversions.; Safety Standard No. 301- 75, *Fuel System Integrity*, promulgated b this agency pursuant to the National Traffic and Motor Vehicle Safety Act, as amended 1974 ('the Act') specifies performance requirements for the fuel systems of new motor vehicles, including school buses, which use fuel with a boiling point above 32 degrees F. (e.g., gasoline).; New vehicles, such as school buses, that have not yet been sold an delivered to a purchaser (here the school district) for purposes other than resale and that have been manufactured in compliance with Safety Standard No. 301-75 may be converted to propane and dual propane/gasoline systems. However, any person or entity, other than the purchaser, such as a manufacturer, dealer, or automobile repair business, who performs the conversion would be considered an alterer under NHTSA regulations.; An alterer is required to attach an additional label to the vehicl certifying that the vehicle, as altered, still complies with all applicable safety standards (49 CFR 567.7). Upon conversion of a new gasoline-powered school bus to a propane-powered school bus, Safety Standard No. 301-75 would cease to apply since propane has a boiling point below 32 degrees F. and the standard applies only to vehicles that use fuel with a higher boiling point. Therefore, the alterer would not be required to certify the school bus's continuing compliance with Safety Standard No. 301-75. However, upon conversion of a new gasoline-powered school bus to a dual powered school bus, Safety Standard No. 301-75 would remain applicable and the alterer would be required to certify the vehicle's continued compliance with that standard and all other applicable safety standards.; The installer of a propane or dual propane/gasoline system in a ne vehicle would be responsible for any safety related defects arising from the method of installation. The manufacturer of the system would be responsible for any safety related defects in the system itself. Thus, if a new school bus were found to contain a safety related defect following the addition of a new fuel system the installer or manufacturer, respectively, would be required to notify vehicle owners of any defects and to remedy these defects. (Sections 151 *et. seq.* of the Act, see enclosure). Also, please note if a propane or a dual propane/gasoline system were installed in a used school bus and was later found to contain any safety related defects, the manufacturer of the system would be responsible for notifying vehicle owners of the defect and for remedying them.; Used vehicles manufactured in accordance with Safety Standard No 301-75, as well as used vehicles manufactured before the effective date of that standard, may also be converted. Nothing in the Act prohibits a vehicle owner from modifying his own vehicles. Moreover, no law administered by the NHTSA prohibits other persons or entities such as manufacturers, distributors, dealers or motor vehicle repair business from modifying used vehicles.; This means that the DeKalb County School District would not b prohibited from converting its gasoline- powered buses, regardless of their date of manufacture, to propane or to dual-powered buses. It also means that if the school district sought to have the conversion done by a manufacturer, distributor, dealer or motor vehicle repair business, none of these persons or entities would be prohibited from doing the work.; However, such persons and entities could be subject to sectio 108(a)(2)(A) of the Act, if they converted used vehicles originally manufactured in compliance with Safety Standard No. 301-75. The section provides in relevant part that:; >>>No manufacturer, distributor, dealer or motor vehicle repai business shall knowingly render inoperative, in whole or part, any device, or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard ....<<<; There is no liability under section 108(a)(2)(A) in connection wit Safety Standard No. 301-75, if one of the listed persons or entities converts a used gasoline-powered vehicle into a propane powered vehicle. Modification of the safety systems in a vehicle that is being converted from one vehicle type to another does not violate section 108(a)(2)(A) so long as the modified systems comply with the safety standards that would have been applicable to the vehicle had it been originally manufactured as the vehicle type to which it is being converted. For example, in converting a used gasoline-powered school bus (originally manufactured in compliance with Safety Standard No. 301-75) to a propane-powered school bus, the converter could not violate section 108(a)(2)(A) with respect to Safety Standard No. 301-75, since this standard, as noted earlier, does not apply to propane-powered school buses.; However, there could be liability under this section in connection wit Safety Standard No. 301-75 if, for example, one of the listed persons or entities converted a used gasoline- powered school bus (originally manufactured in compliance with Safety Standard No. 301-75) into a dual-powered school bus. In this situation, Safety Standard No. 301-75 would continue to apply to the school bus after the conversion. Thus, if in performing the conversion one of the compliance with Standard No. 301-75 while adding the propane system, that person or entity would have violated section 108(a)(2)(A).; I hope that you will find this response helpful. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3830OpenMr. Takeshi Tanuma, Chief Operating Office, Nissan Research & Development, Inc., P.O. Box 8650, Ann Arbor, MI 48104; Mr. Takeshi Tanuma Chief Operating Office Nissan Research & Development Inc. P.O. Box 8650 Ann Arbor MI 48104; Dear Mr. Tanuma: This responds to your April 4, 1984 letter regarding the use of tw certification labels on motor vehicles, with each label containing a portion of the information specified in 49 CFR Part 567 and the two labels together providing all the specified information.; While the certification regulations specify that 'a label' shall b used, the agency has permitted the use of a label in two parts in circumstances which will not lead to confusion and which will satisfy the basic intent of Part 567. In particular, the two portions of the label must be placed in close proximity to each other, to permit individuals to readily find all the specified information and to leave no doubt as to the significance of either portion of the label. Further, the two portions must be oriented in such a manner that the information specified in section 567.4(g) of the certification regulations appears in the required order. As a practical matter, these considerations require that the two portions be affixed to the same vehicle part. While we cannot specify a particular distance as a maximum permissible separation of the two portions of the label, the two portions must be located so as to leave the unmistakable impression that they provide related information.; You also raised the possibility of adding language to one portion o the label to indicate the existence of the other portion and to specify the location of the second portion. While such language is not required, it might be a desirable means of promoting compliance with the considerations discussed above.; 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.