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: aiam4694OpenMrs. Erika Z. Jones Mayer, Brown, & Platt 2000 Pennsylvania Avenue, N.W. Washington, D.C. 20006-1885; Mrs. Erika Z. Jones Mayer Brown & Platt 2000 Pennsylvania Avenue N.W. Washington D.C. 20006-1885; Dear Mrs. Jones: This responds to your letter requesting a confirmatio of your telephone conversation with Mr. Stephen Wood of my staff. In that conversation, he informally stated that the attached letter dated January 5, 1990 from Fidelity Tire Manufacturing Company contained the information necessary to comply with the notification requirements in S5.1 of Federal Motor Vehicle Safety Standard 119 (49 CFR 571.119) for tires and rims not listed in the publication of a specified tire and rim association. This letter confirms that Fidelity's letter would satisfy the requirements of section S5.1. Section S5.1 requires that a listing of the rims which may be used with each tire produced by a manufacturer be provided to the public. The purpose of this requirement is to ensure that the tire will be mounted only on appropriate rims and that the tire will be mounted on vehicles where its load-carrying capacity will be adequate. That section gives manufacturers the option of using the data provided for the tire size and corresponding rims published in certain standardization organization yearbooks or listing the appropriate information 'in a document furnished to dealers of the manufacturer's tires, to any person upon request, and in duplicate to NHTSA .' Fidelity's letter which includes the appropriate dimensional and load-carrying data for the tire and rim appears to satisfy this requirement. I hope this explanation is helpful. Please contact Mr. Marvin Shaw of my staff at (202) 366-2992 if you have any further questions. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2888OpenMr. Michael Pinto, Burke & Burke, 30 Rockefeller Plaza, New York, NY 10020; Mr. Michael Pinto Burke & Burke 30 Rockefeller Plaza New York NY 10020; Dear Mr. Pinto: This is in response to your letter of October 25, 1978, requestin approval of the tread labels Atlas Supply Company proposes to use in satisfaction of the labeling requirements of the Uniform Tire Quality Grading Standards (UTQGS) (49 CFR 575.104(d)(1)(i)(B)). You propose to include the applicable UTQGS grades for a particular tire on a tread label identifying the tire brand, type and size. All possible traction and temperature grades would be depicted with the grades applicable to the specific tire indelibly circled. A separate label would contain the general grading information from Figure 2 of the rule.; Part 575.104(d)(1)(i)(B) requires that each passenger car replacemen tire, other than a snow tire or temporary use spare tire, have affixed a tread label containing both the specific UTQGS grades for the tire and an explanation of the grades in the form illustrated in Figure 2. While the National Highway Traffic Safety Administration (NHTSA) has no objection to the inclusion of the required UTQGS information on the same label with other data such as tire size and brand name, failure to provide the required explanations on the same label with the applicable tire grades is not permitted by the regulation.; While Atlas' proposed tread labels do not meet the present requirement of Part 575.104(d)(1)(i)(B), NHTSA now has under consideration a petition for rulemaking requesting amendment of the UTQG regulation to permit greater flexibility in tread labeling.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1649OpenMr. J. W. Kennebeck, Manager, Emissions, Safety & Development, Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Mr. J. W. Kennebeck Manager Emissions Safety & Development Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Kennebeck: This responds to your October 17, 1974, request for an interpretatio of the term 'walk-in van-type vehicle' as it is used in S4.2.3 of Standard No. 208, *Occupant crash protection*.; This vehicle category is not defined in the standard or in 49 CF S571.3, *Definitions*. Review of its use in the rulemaking which resulted in S4.2.3 makes clear that it includes only a small category of vehicles with a distinctive configuration. Our preamble discussion in Notice No. 9 of Docket No. 69-7 (36 F.R. 4600, March 10, 1971) stated 'Review of the comments and the petitions for reconsideration leads to the conclusion that this type of vehicle [open-body type vehicles], along with convertibles, walk-in van-type vehicles. . . cannot be satisfactorily equipped with a complete passive protection system.'; International Harvester used the term 'walk-in van-type truck' in it comments to describe its 'Metro' delivery vehicle (Comment 69-7-9, December 2, 1970). It requested exclusion of this vehicle from barrier crash testing as too severe for vehicles 'mainly used in low-speed, city-delivery type operations' while maintaining the necessary walk-in feature. Modifications, it argued, would eliminate the walk-in feature and much of the utility of short, high-capacity, city delivery vehicles. It is our interpretation that the term 'walk-in van-type truck' only covers the 'step van' delivery vehicle of which the International Harvester 'Metro' is one example. If you have a question concerning the categorization of one of Volkswagen's vehicles, I suggest that you submit a description of the vehicle to us, on the basis of which we will give you a definitive answer.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam1604OpenMr. Harry L. Cuthbert, Chief Engineer, Eagle International Inc., P.O. Box 4119, 2045 Billy Mitchell Blvd., Brownsville, TX 78520; Mr. Harry L. Cuthbert Chief Engineer Eagle International Inc. P.O. Box 4119 2045 Billy Mitchell Blvd. Brownsville TX 78520; Dear Mr. Cuthbert: This responds to your July 16, 1974, request for approval of the Bendi 'dual circuit air brake system' for use on your buses in satisfaction of Standard No. 121, *Air brake systems.* In a subsequent phone call with Mr. Herlihy of this office, you stated that your only concern was whether the standard requires a parking brake system that meets the axle-by axle retardation force requirements of S5.6.1 and the grade holding requirements of S5.6.2.; The National Highway Traffic Safety Administration is unable t 'approve' plans or prototype systems for compliance with a standard in advance, because there is no way to establish that a vehicle so equipped actually meets the requirements until it has been manufactured.; With regard to your specific question, S5.6 states that each vehicl shall have a parking brake system that meets the requirements of S5.6.1 or S5.6.2 at the manufacturer's option. This means that you are free to choose a system which meets either of these requirements but does not meet both.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3599OpenMr. Robert P. Donley, President, Weldon Incorporated, 2000 South High Street, Columbus, OH 43207; Mr. Robert P. Donley President Weldon Incorporated 2000 South High Street Columbus OH 43207; Dear Mr. Donley: This is in reply to your letter of December 10, 1981, regardin continuing compliance of lighting equipment after repairs.; You have asked the following questions: '1. If the original lens is replaced during a field repair by one no manufactured by the original manufacturer, would the lamp's original certification with FMVSS 108 be nullified?'; Repair of a vehicle in service is irrelevant to its certification Certification is the assurance given by the manufacturer to distributors, dealers, and purchasers, that Federal standards are met by his product upon its sale when new. There is no requirement that the certification be valid for the life of the product.; '2. Must a lamp in use remain in conformance with FMVSS 108 after suc repair is made?'; This is a good question, and the answer is no. When repairs ar necessary there is no Federal legal requirement that the lamp remain in conformance afterwards. However, manufacturers, distributors, dealers, and motor vehicle repair businesses may not alter fully functional lamps in a manner that renders them nonconforming, or substitute nonconforming equipment. This prohibition does not apply to the vehicle owner, his modifications are subject only to State and local restrictions.; '3. If the lamp must remain in conformance with FMVSS 108 after suc repair is made, who is responsible for certifying same?'; As I stated earlier, repairs of used vehicles and equipment are no subject to conformance or certification. However, if a lamp is replaced in its entirety, the manufacturer of the replacement lamp is responsible for certifying conformity to Standard No. 108 because that standard covers replacement equipment of the types you mentioned ('e.g., stop lamp, turn signal lamp, school bus warning lamp, marker lamp').; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2771OpenMr. W.G. Milby, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W.G. Milby Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to your January 11, 1978, letter asking whether severa joints in your school bus must comply with Standard No. 221, *School Bus Body Joint Strength*.; The terms which establish the applicability of the requirements of th standard to a particular section of a school bus body are defined in S4 of the standard. Read together they establish the following test. If the edge of a surface component (made of homogeneous material) that encloses occupant space in a bus comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose, or is a door, window, or maintenance access panel. Applying this test to the several joints to which you refer, it appears that they do not need to comply with the requirements since they connect panels which are considered to be maintenance access panels.; The National Highway Traffic Safety Administration (NHTSA) notes tha maintenance access panels are granted this exception from the requirements because of their need for removal for routine service to underlying components. The NHTSA will not consider all bus walls as maintenance access panels simply because wiring may be present behind them since routine maintenance would not be required on such wiring. Further, should any of the panels to which you refer in your letter not have wiring or other serviceable components requiring routine maintenance behind them, they will not be treated as maintenance access panels.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2614OpenHonorable Clarence D. Long, House of Representatives, Room 200, Post Office Building, Towson, Maryland 21204; Honorable Clarence D. Long House of Representatives Room 200 Post Office Building Towson Maryland 21204; Dear Mr. Long: Your letter of May 9, 1977, to the Federal Trade Commission, on behal of Mr. Edward L. Armstrong, Sr., Baltimore, Maryland, expressing his concern that new passenger car manufacturers will discontinue supplying spare tires, has been referred to this office of the National Highway Traffic Safety Administration, Department of Transportation, for additional consideration and reply.; We believe that Mr. Armstrong's concern deals with the recentl approved 'temporary use' spare tire that will be manufactured and used with some of the new 1978 model automobiles. the use of a temporary use spare tire is not a new concept. These tires have been used with compact sport cars, such as Firebird and Camaro, since 1967. The further development of these spare tires has been fostered by the desire if the U.S. automobile manufacturers to produce small, lightweight cars in furtherance of the national energy conservation program. I am sure that you have noticed the new 1977 models by some domestic automobile manufacturers are, in fact, smaller. Of course, the development of these smaller, lightweight, energy-efficient automobiles has resulted in a substantial reduction in usable car trunk space, and therefore, providing a second reason to develop a spare tire which takes less storage space than a conventional tire.; Since this spare tire is designed for use in the nation's highways, i must conform to the minimum performance requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 109, *New Pneumatic Tires - Passenger Cars*, for strength, endurance and high speed performance, For your information, we have enclosed a copy of this standard.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2596OpenMr. Eric E. Gough, Staff Assistant (Technical), Lucas Industries North America, Inc., Two Northfield Plaza, Troy, MI 48084; Mr. Eric E. Gough Staff Assistant (Technical) Lucas Industries North America Inc. Two Northfield Plaza Troy MI 48084; Dear Mr. Gough: This is in reply to your letter of May 13, 1977, to the Administrato asking whether the circuitry diagram that you enclosed would allow compliance with S4.5.2 of Federal Motor Vehicle Safety Standard No. 108.; Paragraph S4.5.2 requires that 'each vehicle shall have a means fo indicating to the driver when the upper beams of the headlamps are on that conforms to SAE Recommended Practice J564a, April 1964 ....' Your diagram appears to meet the specifications of J564a allowing compliance of the system with S4.5.2 when installed in a motor vehicle. The entity legally responsible for compliance with S4.5.2, of course, is the vehicle manufacturer who must certify that its products meet all applicable Federal motor vehicle safety standards.; Yours truly, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1158OpenMr. James W. Livsey, The Southern Connecticut Gas Co., 880 Broad Street, Bridgeport, Connecticut 06609; Mr. James W. Livsey The Southern Connecticut Gas Co. 880 Broad Street Bridgeport Connecticut 06609; Dear Mr. Livsey: This is in reply to your letter to Mr. David Snyder of this agenc regarding information on tests performed on recapped tires, specifically, data comparing failure characteristics of retreaded tires with those of new tires.; The NHTSA does not presently have test data of the specific type yo request. We are attempting to obtain that data through research contracts with outside parties, and results of that research, when they are received, will be placed in the rulemaking docket regarding retreaded tires. Other test data for retreaded tires have been placed in this docket (Docket No. 1-8), which is open for public inspection at NHTSA headquarters, 400 7th Street, S.W., Washington, D.C.; Certain studies have been conducted on the failure rates of tires, an some comparative data have been complied. One volume with which we are familiar summarizes studies which provided information of this type. It is, Brenner and Harvey, Tire Use Survey, the Physical Condition, Use and Performance of Passenger Car Tires in the United States of America, NBS Technical Note 528, (National Bureau of Standards U.S. Department of Commerce). Copies are available from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. It should be ordered by SD Catalog No. C13.46:528, prepaid, at 60 a copy.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2228OpenMr. 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 |
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.