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: aiam3144OpenMr. H. J. T. Young, Vice President - Technical Affairs, SEV Corporation 33201 Harper Avenue, St. Clair Shores, MI 48082; Mr. H. J. T. Young Vice President - Technical Affairs SEV Corporation 33201 Harper Avenue St. Clair Shores MI 48082; Dear Mr. Young: This is in reply to your letter of September 24, 1979, to Mr. Vinson o this office in which you requested an interpretation S4.1.1.19 of Federal Motor Vehicle Safety Standard No. 108.; S4.1.1.19 states: >>>A lamp manufactured on or after January 1, 1974 and designed to us a type of bulb that has not been assigned a mean spherical candlepower rating by its manufacturer and is not listed in SAE Standard J573d 'Lamp Bulbs and Sealed Units', December 1968, shall meet the applicable requirements of this standard when used with any bulb of the type specified by the lamp manufacturer, operated at the bulb's design voltage. A lamp that contains a sealed-in bulb shall meet these requirements with the bulb operated at the bulb's design voltage.<<<; It is noted that this paragraph consists of two sentences. You hav asked whether the 'lamp' and 'bulb' of the second sentence are the same 'lamp and bulb' of the first sentence.; The answer is no. The first sentence would require testing, at th bulb's design voltage, of bulbs used in sealed beam headlamps but not of bulbs used in, for example, taillamps. The former, though listed in J573d (Table 2), is not assigned a mean spherical candlepower rating since these bulbs emit shaped beams while the latter is used in the sealed lamp, it is tested at the bulb's design voltage rather than using the rated mean spherical candlepower. Furthermore, the rulemaking history of the paragraph clearly indicates that the two requirements are separate. As the agency noted in the preamble to the proposal, 'The proposal specifies that when no rating has been assigned by the bulb manufacturer or the SAE *or* if the lamp is sealed and the bulb cannot be replaced, the bulb shall be operated at design voltage' (emphasis supplied) (38 FR 16230).; You noted that your question relates to the voltage required b Standard No. 108 for the photometric testing of a sealed beam headlamp that utilizes a European halogen bulb that meets ECE Regulation 37.; Since J579c requires the test voltage to be 12.8 volts for all th sealed beam bulbs, the photometric test should be at 12.8 volts and not at the so-called 'system voltage' of 12 volts.; I hope this is responsive to your request. |
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ID: aiam2107OpenMr. John B. White, Engineering Manager, Technical Information Dept., Michelin Tire Corporation, P. O. Box 3467, New Hyde Park P. O., NY 11040; Mr. John B. White Engineering Manager Technical Information Dept. Michelin Tire Corporation P. O. Box 3467 New Hyde Park P. O. NY 11040; Dear Mr. White: This is in response to your letter of October 17, 1975, concerning th importation into the United States of tires that will be mounted on trucks intended for export from the United States.; 49 CFR Part 571.7(d) and Section 108(b)(5) of the National Traffic an Motor Vehicle Safety Act of 1966 specify that no Federal Motor Vehicle Safety Standards (FMVSS) apply to; >>>a motor vehicle or item of motor vehicle equipment intended solel for export, and so labeled or tagged on the vehicle or item itself and on the outside of the container, if any, which is exported.<<<; Therefore, tires which Michelin manufactures for sale directly to truck manufacturer who will mount them on trucks which are intended solely for export need not comply with Standard No. 119, *New Pneumatic Tires for Vehicles Other than Passenger Cars*. When imported and shipped to the truck manufacturer, the tires must bear a label or tag indicating intent to export. Such a label must also appear on the outside of the container, if any, in which the tires are shipped. Importation of such tires is permitted by 19 CFR 12.80(b)(1)(ii), provided they are so labeled. A label need not remain on the tires after they have been mounted on the trucks, provided that the trucks bear similar labels.; Because these tires are not subject to any FMVSS and are beyond th scope of any expected defect notification and remedy program, Michelin Tire Corporation is not subject to the requirements of 49 CFR Part 574, *Tire Identification and Recordkeeping*, with respect to them.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2104OpenMr. John B. White, Engineering Manager, Technical Information Dept., Michelin Tire Corporation, P.O. Box 3467, New Hyde Park P.O., New York 11040; Mr. John B. White Engineering Manager Technical Information Dept. Michelin Tire Corporation P.O. Box 3467 New Hyde Park P.O. New York 11040; Dear Mr. White: This is in response to your letter of October 17, 1975, concerning th importation into the United States of tires that will be mounted on trucks intended for export from the United States.; 49 CFR Part 571.7(d) and Section 108(b)(5) of the National Traffic an Motor Vehicle Safety Act of 1966 specify that no Federal Motor vehicle Safety Standards (FMVSS) apply to; >>> a motor vehicle or item of motor vehicle equipment intended solel for export, and so labeled or tagged on the vehicle or item itself and on the outside of the container, if any, which is exported.<<<; Therefore, tires which Michelin manufactures for sale directly to truck manufacturer who will mount them on trucks which are intended solely for export need not comply with Standard No. 119, *New Pneumatic Tires for Vehicles Other than Passenger Cars*. When imported and shipped to the truck manufacturer, the tires must bear a label or tag indicating intent to export. Such a label must also appear on the outside of the container, if any, in which the tires are shipped. Importation of such tires is permitted by 19 CFR 12.80(b)(1)(ii), provided they are so labeled. A label need not remain on the tires after they have been mounted on the trucks, provided that the trucks bear similar labels.; Because these tires are not subject to any FMVSS and are beyond th scope of any expected defect notification and remedy program, Michelin Tire Corporation is not subject to the requirements of 49 CFR Part 574, *Tire Identification and Recordkeeping*, with respect to them.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4198OpenMr. John C. Hilliard, Chairman & Techncial (sic) Director, Combustion and Fuel Research, Inc., 847-9 South Wagner Road, Ann Arbor, MI 48103; Mr. John C. Hilliard Chairman & Techncial (sic) Director Combustion and Fuel Research Inc. 847-9 South Wagner Road Ann Arbor MI 48103; Dear Mr. Hilliard: Thank you for your letter of July 1, 1986, asking how our regulation would affect the placement of the steering wheel on delivery vehicles. You asked whether there are any State or Federal regulations which would prevent the installation of a right hand drive steering wheel. As discussed below, the National Highway Traffic Safety Administration (NHTSA) has not issued any safety standards that would prohibit the installation of a right hand drive steering wheel. As to State laws, I suggest you check with the Department of Transportation in the States where your client wants to use the vehicles.; Some background information about our agency and its standards may b of assistance to you. NHTSA has the authority to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the National Traffic and Motor Vehicle Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet our safety standards. The agency periodically tests vehicles and equipment items for compliance with the standards, and also investigates alleged safety-related defects.; We do not have any standards that prohibit the use of a right han drive steering system. We have, however, issued two safety standards (Standard Nos. 203 and 204) that set performance requirements which apply to any steering system, whether left or right hand drive, installed in new passenger cars and light trucks, buses, and multipurpose passenger vehicles. A copy of each of these standards is enclosed.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam5277OpenBarry H. Wells, M.D. 600 Ridgely Avenue, Suite 130 Annapolis, MD 21401; Barry H. Wells M.D. 600 Ridgely Avenue Suite 130 Annapolis MD 21401; Dear Dr. Wells: Thank you for your letter describing a device yo called an 'Emergency Brake Technology' (E.B.T.) system that you believe would eliminate jackknifing and improve the stopping distances of tractor trailers. A video tape accompanying your letter stated that the E.B.T. system operates by having a metal wedge slide below each wheel in response to an action by the driver. You requested the opportunity to testify or submit written comments about the benefits of this device. You also requested that the agency test the E.B.T. system. As Marvin Shaw of my staff explained to you, NHTSA issued a notice of proposed rulemaking (NPRM) on September 28, 1993, that addresses the lateral stability and control of medium and heavy vehicles. The agency is proposing to require these vehicles to be equipped with an antilock brake system (ABS) and to comply with a 30 mph braking-in-a-curve test on a low coefficient of friction surface. Mr. Shaw advised you that while the agency does not anticipate holding a public hearing on this rulemaking, you could submit written comments to the NPRM. In addition, we have submitted this correspondence, including your incoming letter and the video tape, to the public docket. We regret that we are unable to fulfill your request for NHTSA to test the E.B.T. system. Given our limited research budget, it is not possible for us to test every automotive safety-related piece of equipment that is introduced into the marketplace. I hope this information is helpful. If you have any further questions about NHTSA's activities, please feel free to contact Marvin Shaw at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam3384OpenMr. Charlton C. Davis, Davis Trailer Mfg. Co., Rte 1, Highway 78E, Loganville, Georgia 30249; Mr. Charlton C. Davis Davis Trailer Mfg. Co. Rte 1 Highway 78E Loganville Georgia 30249; Dear Mr. Davis: This responds to your November &, 1980, letter to Mr. Kratzke of m staff, in which you requested information concerning the legality of using welded mobile home axles and mobile home tires on trailers.; We have no regulations concerning the axles which may be used o trailers. However, the use if mobile home tires on new trailers would violate Federal Motor Vehicle Safety Standard No. 120 (49 CFR S571.120). For your information, I have enclosed a copy of this standard. Section S5.1 of the standard requires all new trailers equipped with tires for highway service to use tires that comply with either Standard No. 119, *New Pneumatic Tires for Use on Motor Vehicles Other Than Passenger Cars*, or Standard No. 109, *New Pneumatic Tires--Passenger Cars*, tires which have the label 'For Mobile Home Use Only' have been expressly exempted from the performance requirements of Standard No. 119. Because of the exemption, these tires may only be used on mobile homes. Therefore, the use of these tires on new trailers would render the trailers in violation of Standard No. 120. A manufacturer using these tires on a new trailer would face a fine of up to $1,000 for each mobile home tire used, pursuant to the provision of section 108 and 109 of the national Traffic and Motor Vehicle Safety Act as amended (15 U.S.C. 1397 and 11398). If you are aware of any such violations, the agency would appreciate any information you could supply.; As I Have stated above, we have no regulations specifying performanc requirements for the axles on trailers. If you have any further questions or need any further information on this subject, please contact Mr. Kratzke at (202) 426-2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1997OpenMr. Carl Morton, County of Los Angeles Road Department, 5530 West 83rd Street, Los Angeles, California 90045; Mr. Carl Morton County of Los Angeles Road Department 5530 West 83rd Street Los Angeles California 90045; Dear Mr. Morton: Please forgive the delay in responding to your letter of April 28 1975, concerning tires used on pull brooms.; Federal Motor Vehicle Safety Standard No. 119, *New pneumatic tires fo vehicles other than passenger cars*, (copy enclosed), specifies labeling and performance requirements for all tires designated for use on pull brooms. This standard applies to all such tires manufactured on or after March 1, 1975. There is presently no requirement, however, that vehicles be equipped with tires conforming to the standard. the National Highway Traffic Safety Administration has proposed and is considering the issuance of a new Standard No. 120, *Tire Selection and Rims for motor vehicles other than passenger cars*, which would require all new pull brooms manufactured after its effective date to be equipped with tires conforming to Standard No. 119.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam1998OpenMr. Carl Morton, County of Los Angeles Road Department, 5530 West 83rd Street, Los Angeles, California 90045; Mr. Carl Morton County of Los Angeles Road Department 5530 West 83rd Street Los Angeles California 90045; Dear Mr. Morton: Please forgive the delay in responding to your letter of April 28 1975, concerning tires used on pull brooms.; Federal Motor Vehicle Safety Standard No. 119, *New pneumatic tires fo vehicles other than passenger cars*, (copy enclosed), specifies labeling and performance requirements for all tires designed for use on pull brooms. This standard applies to all such tires manufactured on or after March 1, 1975. There is presently no requirements, however, that vehicles be equipped with tires conforming to the standard. The National Highway Traffic Safety Administration has proposed and is considering the issuance of a new Standard No. 120, *Tire selection and rims for motor vehicles other than passenger cars*, which would require all new pull brooms manufactured after its effective date to be equipped with tires conforming to Standard No. 119.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam3895OpenMr. Giorgio Kirchner, Segreteria Generale, Federazione Italiana Fuoristrada, 20131 Milano, Via Capranica, 4, ITALY; Mr. Giorgio Kirchner Segreteria Generale Federazione Italiana Fuoristrada 20131 Milano Via Capranica 4 ITALY; Dear Mr. Kirchner: This responds to your letter asking for information about U.S. Federa laws covering tires. For your information, I have enclosed a copy of a letter I sent to a Brazilian tire manufacturer last year, explaining all of the requirements which must be satisfied by a foreign manufacturer selling tires in the United States and enclosing copies of the pertinent regulations.; You stated that you were particularly interested in knowing th meanings and the corresponding values of identification symbols required to appear on sidewalls of tires subject to Standard No. 119. You listed as examples of symbols you were interested in load range and 'P.R.'; The load range is a letter between 'A' and 'N', with an A being th lowest load range and N being the highest. Load ranges are assigned to tires for use on motor vehicles other than passenger cars because such tires may have identical physical dimensions and, therefore, identical size designations, but widely differing load-carrying capabilities. To ensure that these ties are used only in situations where their load-carrying capability is sufficient, section S6.5(j) of Standard No. 119 requires a letter designating the load range to appear on the sidewall of each tire for use on motor vehicles other than passenger cars. If you are interested in learning the load-carrying capability of the load ranges assigned to a particular tire size, you should contact one of the standardization organizations listed in section S5.1(b) of the enclosed copy of Standard No. 119.; I believe that the symbol 'P.R.' refers to the ply rating for a tire The ply rating is an older system which performed the same function now served by the load range. Under the ply rating system, tires were rated from 2 to 24 plies, with the lower numbers indicating a less load- carrying capability. Standard No. 119 does *not* require that a ply rating appear on the sidewall of tires. I have enclosed a copy of a page from the most recent yearbook published by the American standardization organization, the Tire & Rim Association, which shows how to convert a ply rating to the appropriate load range.; If you need further information or have any questions on the enclose materials, please feel free to contact me.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1902OpenMr. William J. Moede, Olson Trailer & Body Builders Co.,2740 S. Ashland, P.O. Box 2445, Green Bay, WI 54306; Mr. William J. Moede Olson Trailer & Body Builders Co. 2740 S. Ashland P.O. Box 2445 Green Bay WI 54306; Dear Mr. Moede: This responds to your April 7, 1975, questions whether the Olso two-axle, three-axle, and four-axle 'land-hog' trailers would qualify for exclusion from Standard No. 121, *Air brake systems*, until September 1, 1976, as 'heavy hauler' trailers or if equipped with an axle with a gross weight rating (GAWR) of 24,000 pounds or more.; The trailers you describe do not appear to qualify as a heavy haule trailer because they do not appear to have brake lines which adapt to separation or extension of the vehicle frame, or a bed height of 40 inches or less in the unloaded condition.; Standard No. 121 applies to most air-brake vehicles. Section S3 of th standard does exclude any vehicle manufactured before September 1, 1976, that has a gross axle weight rating for any axle of 24,000 pounds or more.; 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.