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: aiam2230OpenMr. A. G. Colburn, Director of Trailer Design, Lufkin Industries, Inc., P.O. Box 848, Lufkin, TX 75901; Mr. A. G. Colburn Director of Trailer Design Lufkin Industries Inc. P.O. Box 848 Lufkin TX 75901; Dear Mr. Colburn: This responds to your February 6, 1976, questions whether Lufki Industries may, as an incomplete vehicle manufacturer, build 'incomplete chassis trailers' that do not have brakes installed that comply with Standard No. 121, *Air Brake Systems*, and whether Lufkin may tow the 'incomplete chassis trailers' over the highway to the final-stage manufacturer without brakes that conform to Standard No. 121.; Lufkin's activities are regulated by Part 568 of Title 49 of the Cod of Federal Regulations, if the 'incomplete chassis trailers' qualify as 'incomplete vehicles.' A copy is enclosed for your information. Part 568 does not require the incomplete vehicle to meet all applicable safety standards, but S 568.4 does require a statement of the status of an incomplete vehicle's conformity with all applicable standards.; In answer to your second question, the NHTSA permits the use of a incomplete vehicle on the public highways for the purpose of transit between the incomplete vehicle manufacturer and subsequent manufacturers, but for no other purpose, until such time as the vehicle complies with all Federal motor vehicle safety standards applicable to it as completed. This ruling by the NHTSA does not relieve the manufacturer or shipper from any applicable requirement imposed on the incomplete vehicle by other Federal, State, or local authority.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam4408OpenMr. 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 September 18, 1987, with respect t a new headlamp design of very low profile. The height of the headlamp is less than that required by dimension A of Figure 4, of Standard No. 108, and you have asked NHTSA: 'to make the height of the headlamp lower than dimension A...on condition that the additional adaptor will be provided as original equipment'.; You are under the impression that our interpretation to you dated Marc 26, 1987, relating to acceptability of a headlamp lens with a 60 degree angle was an affirmative one conditioned upon the provision of an adaptor as original equipment. In fact, we only advised you that such an adaptor should be provided, not that it was required. With respect to your present letter, dimension A is established by Standard No. 108 and cannot be modified except through rulemaking, whether or not an adaptor is provided.; If you wish to submit a petition for rulemaking to amend dimension A o Figure 4 we shall be pleased to consider it. The agency also intends to publish in the near future a Notice asking comments on various aspects of vehicle headlamp aim and aiming methods which you may wish to consider in relation to your new headlamp design.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3042OpenMr. D.J. Schrum, Manager, Product Compliance, Subaru of America, Inc., 7040 Central Highway, Pennsauken, NJ 08109; Mr. D.J. Schrum Manager Product Compliance Subaru of America Inc. 7040 Central Highway Pennsauken NJ 08109; Dear Mr. Schrum: This is in response to your letter of June 4, 1979, concerning Subaru' obligation to provide to prospective motor vehicle purchasers an explanation of the Uniform Tire Quality Grading (UTOG) Standards (49 CFR 575.104(d)(1)(ii)). You ask whether Subaru must provide UTOG information to prospective purchasers prior to April 1, 1980, in view of the fact that all motor vehicles sold by your company are equipped with radial tires.; With respect to radial tires, the effective date for all requirement of the UTOG regulation, other than the molding requirement of paragraph (d)(1)(i)(A) and the first purchaser requirement of paragraph (d)(1)(iii), is April 1, 1980. Therefore, manufacturers, such as Subaru, which offer for sale only motor vehicles equipped with radial tires, need not provide UTOG information for examination by prospective purchasers prior to April 1, 1980.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4006OpenWarren F. B. Lindsley, Esq., Camel Square Suite 200E, 4350 East Camelback Road, Phoenix, AZ 85018; Warren F. B. Lindsley Esq. Camel Square Suite 200E 4350 East Camelback Road Phoenix AZ 85018; Dear Mr. Lindsley: This is in reply to your letter of July 3, 1985, to Mr. Vinson of m staff, with reference to the center high-mounted stop lamp, in which you have asked 'whether a light which pulsates a few times and then assumes a steady state meets the requirements of the code.'; As Mr. Vinson explained to you, a center high-mounted stop lam installed as original equipment on a passenger car manufactured before September 1, 1986, must be steady-burning in use, but is permitted to flash automatically with the hazard warning system. As of September 1, 1986, original equipment lamps must only be activated upon application of the service brakes, and can only be steady-burning. A 'light that pulsates a few times then assumes a steady state' would not fulfill this requirement.; The standard does not cover aftermarket equipment for vehicles no originally manufactured with the center high-mounted stop lamp. For this application, the law of each State where a retrofitted car would be operated would determine the legality of a pulsating/steady state lamp. The agency, of course, would prefer that aftermarket equipment conform as closely as possible to original vehicle equipment specifications. We believe that standardization of rear signals minimizes the possibility of creating confusion to following drivers in situations where immediate action is essential to avoid a rear end collision.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam3894OpenMr. Bernt Svensson, Marketing Director, Viskafors Gummifabrik AB, Box 2059, S-515 02 Viskafors, SWEDEN; Mr. Bernt Svensson Marketing Director Viskafors Gummifabrik AB Box 2059 S-515 02 Viskafors SWEDEN; Dear Mr. Svensson: This responds to your letter to Ms. Kathleen DeMeter of my staff asking for information on how to get a new temporary spare tire size included in the tire tables following Standard No. 109, * New Pneumatic Tires -- Passenger Cars* (49 CFR S571.109). The agency rescinded tire tables in Standard No. 109 in a final rule published at 46 FR 61473, December 17, 1981. I have enclosed a copy of that rule together with a current copy of Standard No. 109 for your records.; Section S4.4.1 requires tire manufacturers to provide a listing of th rims that may be used with each tire size it produces. Section S4.2.1(c) requires a tire's load rating be the load rating for that size specified in a submission under S4.4.1. This may be provided by the manufacturer in a document furnished to each of the manufacturer's dealers, to this agency, and to the pubic upon request. Alternatively, the manufacturer may use the data for that tire size shown in a current publication of one of the standardization organization listed in S4.4.1(b). Your company will have to use one of these two means of complying with this requirement, instead of relying on the tire tables, as was formerly done.; The current publication of the American standardization organizatio the Tire & Rim Association) shows no listing for the tire size about which you inquired. It is possible that the size is listed by one of the other standardization organization of your choosing or submit the data directly to this agency, all your dealers and the public, upon request.; Should you have any further questions on this matter, please contac Mr. Stephen Kratzke of my staff at this address.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1568OpenMr. C.J. Baker, Peerless Division, Royal Industries, P.O. Box 447, Tualatin, OR 97062; Mr. C.J. Baker Peerless Division Royal Industries P.O. Box 447 Tualatin OR 97062; Dear Mr. Baker: This responds to your July 23, 1974, question concerning th certification responsibility of a small manufacturer of trailers that must conform to Standard No. 121, *Air brake systems*. You ask if road testing of any or all vehicles produced would be necessary to satisfy the requirements.; A manufacturer must 'exercise due care' in certifying that the vehicle manufactured by him comply with the applicable standards (National Traffic and Motor Vehicle Safety Act of 1966, S 108(b)(2), 15 U.S.C. S 1392(b)(2)). What constitutes due care in a particular case depends on all relevant facts, including such things as the time to elapse before a new effective date, the availability of test equipment to small manufacturers, the limitations of current technology, and above all the diligence evidenced by the manufacturer.; A small manufacturer of standard and custom trailers might fulfill hi due care responsibility to assure that each of his trailers is capable of meeting the standard in several ways. For example, he could establish categories of models which share a common brake and axle system and certify them all on the basis of tests on the most adverse configuration in the category. Calculations should be written down in such a case to establish that reasonable care was taken in these decisions.; Alternatively, joint testing might be undertaken with a trad association or with a major supplier of brake and axle components. In the case of standard models, you might be able to rely on the supplier's warranty of his products' capacities.; Neither of these methods would require road testing of each vehicl manufactured, nor would every model have to be road tested. A manufacturer must simply satisfy himself that the trailer is capable of meeting the stopping performance requirements if it were tested by the NHTSA.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3322OpenMr. Terry Coleman, Codes and Safety Manager, Airstream, Jackson Center, OH 45334; Mr. Terry Coleman Codes and Safety Manager Airstream Jackson Center OH 45334; Dear Mr. Coleman: This responds to your June 13, 1980, letter asking whether your compan would be considered a chassis-cab manufacturer subject to the labeling requirements of Part 567, *Certification*. You indicate that you take another manufacturer's incomplete chassis with a motor and add to it a cab and body with bumpers, mirrors, and exterior trim. This vehicle is then sent to a final-stage manufacturer for final completion. We would not consider you to be a chassis-cab manufacturer subject to the certification requirements.; As you know, a chassis-cab is defined in Part 567 as 'an incomplet vehicle, with a completed occupant compartment, that requires only the addition of cargo carrying, work performing, or load bearing components to perform its intended functions.' The incomplete vehicle upon which your manufacturing operation begins is simply a chassis without the cab. As such, that vehicle is subject to the incomplete vehicle document requirements of Part 568, but it is not subject to the chassis-cab certification requirements.; Your modification adds on a bus body which then needs final work befor it can be used. Since you do not complete the occupant compartment as required by the definition of 'chassis-cab', you are not required to attach a certification label. You are simply an intermediate manufacturer. The final- stage manufacturer would attach the only label to the vehicle.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3321OpenMr. Terry Coleman, Codes and Safety Manager, Airstream, Jackson Center, OH 45334; Mr. Terry Coleman Codes and Safety Manager Airstream Jackson Center OH 45334; Dear Mr. Coleman: This responds to your June 13, 1980, letter asking whether your compan would be considered a chassis-cab manufacturer subject to the labeling requirements of Part 567, *Certification*. You indicate that you take another manufacturer's incomplete chassis with a motor and add to it a cab and body with bumpers, mirrors, and exterior trim. This vehicle is then sent to a final-stage manufacturer for final completion. We would not consider you to be a chassis-cab manufacturer subject to the certification requirements.; As you know, a chassis-cab is defined in Part 567 as 'an incomplet vehicle, with a completed occupant compartment, that requires only the addition of cargo carrying, work performing, or load bearing components to perform its intended functions.' The incomplete vehicle upon which your manufacturing operation begins is simply a chassis without the cab. As such, that vehicle is subject to the incomplete vehicle document requirements of Part 568, but it is not subject to the chassis-cab certification requirements.; Your modification adds on a bus body which then needs final work befor it can be used. Since you do not complete the occupant compartment as required by the definition of 'chassis-cab', you are not required to attach a certification label. You are simply an intermediate manufacturer. The final- stage manufacturer would attach the only label to the vehicle.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4853OpenMr. Rueben K. Brown Product Engineer Crane Carrier Company P.O. Box 582891 1925 North Sheridan Tulsa, OK 74158; Mr. Rueben K. Brown Product Engineer Crane Carrier Company P.O. Box 582891 1925 North Sheridan Tulsa OK 74158; Dear Mr. Brown: This responds to your letter of March 12, 199 requesting an interpretation of the applicability of the spike stop requirement in Standard No. 105 to school buses with GVWR greater than 10,000 lbs. While school buses are required by S5.1 to be capable of meeting the requirements of S5.1.1 through S5.1.6, the spike stop requirement in S5.1.6 is only applicable to vehicles with a GVWR of 10,000 lbs. or less. Therefore, school buses with a GVWR greater than 10,000 lbs are not required to be capable of meeting the spike stop requirement. I hope this information has been helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam4857OpenMr. Rueben K. Brown Product Engineer Crane Carrier Company P.O. Box 582891 1925 North Sheridan Tulsa, OK 74158; Mr. Rueben K. Brown Product Engineer Crane Carrier Company P.O. Box 582891 1925 North Sheridan Tulsa OK 74158; Dear Mr. Brown: This responds to your letter of March 12, 199 requesting an interpretation of the applicability of the spike stop requirement in Standard No. 105 to school buses with GVWR greater than 10,000 lbs. While school buses are required by S5.1 to be capable of meeting the requirements of S5.1.1 through S5.1.6, the spike stop requirement in S5.1.6 is only applicable to vehicles with a GVWR of 10,000 lbs. or less. Therefore, school buses with a GVWR greater than 10,000 lbs are not required to be capable of meeting the spike stop requirement. I hope this information has been helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice 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.