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
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ID: aiam2205OpenMr. Charles A. Smith, Director, Alaska Traffic Safety Bureau, Pouch N, Juneau 99811; Mr. Charles A. Smith Director Alaska Traffic Safety Bureau Pouch N Juneau 99811; Dear Mr. Smith:#This in (sic) in response to a request by Mr. Willia Hall, National Highway Traffic Safety Administration (NHTSA) Regional Administrator for Region X, for a review of Federal Motor Vehicle Safety Standard No. 104, *Windshield Wiping and Washing Systems* with special consideration of the comments of Mr. Robertson in his memorandum of November 24, 1975.#It is the opinion of this agency that Standard No. 104 is appropriate for the State of Alaska. The essential feature of a wiping system, as far as safety is concerned, is its ability to clear a specific portion of the windshield. The number of wipers necessary to provide the driver with a sufficient field of view is immaterial so long as the minimum percentages of critical areas are washed and wiped. These areas are established in the standard and are determined by the angles from the driver's eye position over which the windshield must be kept clear to provide a proper field of view. While targets of driver attention and environmental conditions may differ from state to state, if the critical areas are clear, the field of view provided to the driver is sufficient. The 1976 Scirocco (sic) appears to provide the required field of view.#The question therefore becomes whether the Federal standard on windshield wipers is intended to cover all aspects of wiping systems. If so, the situation is analogous to that presented to the court in *Motorcycle Industry Council v. Younger*, No. CIV S74-126(E.D.Cal. 1974) which resulted in a holding that Standard No. 108 did preempt an inconsistent state regulation in the field of lighting requirements. The NHTSA has determined that the standard on windshield wiping systems, No. 104, is intended to leave the number of wipers to the discretion of the manufacturers. Under *Thorpe v. Housing Authority of Durham*, 393 U.S. 268 (1969), and *Chrysler v. Tofany*, 419 F2d 499, 511-12 (2d Cir, 1969), the interpretation of this question by the administering agency is 'of controlling weight unless it is plainly erroneous or inconsistent with the regulation.' Thus, a state regulation differing from the standard would impair the Federal superintendence of the field within the meaning of the doctrine set forth in *Florida Lime & Avocado Growers v. Paul*, 373 U.S. 132, 141-142(1963) and be preempted under section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966, U.S.C. 1392(d).#Yours truly, Frank Berndt, Acting Chief Counsel; |
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ID: aiam0392OpenMr. Frank S. Elliott, Assistant to the Vice-President- Treasurer, Grove Manufacturing Company, Shady Grove, PA 17256; Mr. Frank S. Elliott Assistant to the Vice-President- Treasurer Grove Manufacturing Company Shady Grove PA 17256; Dear Mr. Elliott: This is in reply to your letter of June 22, 1971, regarding the Tir Identification and Record Keeping Regulation (49 CFR 574).; You have asked if Grove Manufacturing Company is a 'Motor Vehicl Manufacturer' within the meaning of section 574.10 of the regulation. As you indicated in your letter, you are the final-stage manufacturer of a truck mounted hydraulic crane, and as such, you are considered the vehicle manufacturer under section 568.3 of Vehicles Manufactured in Two or More Stages (49 CFR 568). As the vehicle manufacturer, you are required to maintain records of the name and address of the first purchaser of your vehicles, for purposes other than resale, along with a record of the tires on the vehicle at the time it is shipped.; Enclosed for convenience are copies of both regulations. For your information, I would direct you to section 568.7 which allow an incomplete vehicle manufacturer to assume all the responsibilities of a manufacturer, this would include the record keeping responsibilities of Part 574.; If we can be of further assistance, please feel free to write. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam3947OpenMr. John K. Park, Consultant, Hyundai Motor Company, 7314 Nineteen Mile Road, Sterling Heights, MI 48074; Mr. John K. Park Consultant Hyundai Motor Company 7314 Nineteen Mile Road Sterling Heights MI 48074; Dear Mr. Park: This is in reply to your letter of May 3, 1985, asking for a interpretation of the center high-mounted stoplamp provisions of Motor Vehicle Safety Standard No. 108.; You stated that the Hyundai lamp is 'obscured slightly by the rea window wiper arm' but that 'the effective projective luminous lens area exceeds 4.5 square inches'. You asked whether the wiper arm is considered an obstruction to the lamp.; The agency answered a similar question from Mazda in its response t petitions for reconsideration of the stoplamp requirements published on May 17, 1984 (copy enclosed). NHTSA advised that compliance of the lamp would be judged with a rear wiping system in the design off position, and that photometric conformance would be judged thereby. The lamp must be positioned in such a way that it will comply when tested at any of the photometric test points specified in the standard with the wiper system in the design off position.; I hope that this answers your question. Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam0668OpenMr. Vernon R. Verjinsky, Street Superintendent, Department of Engineering, 441 West Grand Avenue, Wisconsin Rapids, WI 54494; Mr. Vernon R. Verjinsky Street Superintendent Department of Engineering 441 West Grand Avenue Wisconsin Rapids WI 54494; Dear Mr. Verjinsky: Mr. Carter has asked me to reply to your letter of March 3, 1972, i which you ask who has the responsibility for certification of vehicles manufactured in two or more stages.; Paragraph 567.5(a) of Title 49 of the Code of Federal Regulation states, '. . . Except as provided in paragraphs (b) and (c) of this section, each final-stage manufacturer, as defined in S 568.3 of this chapter, of a vehicle manufactured in two or more stages shall affix to each vehicle a label, of the type and in the manner and form described . . . .' Paragraphs (b) and (c) are concerned with incomplete and intermediate manufacturers who assume legal responsibility for all duties and liabilities imposed by the National Traffic and Motor Vehicle Safety Act of 1966 (the Act), with respect to the vehicle as finally manufactured.; Paragraph 568.3 states, ''Final- stage' manufacturer means a person wh performs such manufacturing operations on an incomplete vehicle that it becomes a completed vehicle.'; The subject is also dealt with in the Preamble to Part 568 - Vehicle Manufactured in Two or More Stages. ' . . . By its definition, a completed vehicle is one that requires no further manufacturing operations in order to perform its intended function other than the attachments of readily attachable components and minor finishing operations. If a manufacturer installs a component that is not readily attachable, such as a fifth wheel, then he is a final-stage manufacturer even though his contribution to the overall vehicle may appear small . . .; 'In the event that a 'readily attachable component' is a componen regulated by the standards, such as a mirror or a tire, the final-stage manufacturer must assume responsibility and certify the vehicle even though he does not install the particular component. Otherwise, the installer of mirrors and tires would be considered a final-stage manufacturer, a status that he would probably find unacceptable and that would tend to make certification less meaningful . . . .'; I am enclosing Parts 567 and 568 of Title 49 of the Code of Federa Regulations. If you have further questions I will be pleased to answer them.; Sincerely, Francis Armstrong, Director, Office of Standard Enforcement, Motor Vehicle Programs; |
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ID: aiam5190OpenMr. Ray Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood, CA 91601; Mr. Ray Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood CA 91601; "Dear Mr. Kesler: This responds to your follow-up letter to the agenc in which you request further interpretation of the requirements in Standard No. 111 relating to convex mirrors. Specifically, you asked about how section S5.4.1, which limits the radii of curvature's permissible variance, relates to S12, which specifies the procedures for determining a convex mirror's average radius of curvature. I am pleased to have this opportunity to respond to your request. As Marvin Shaw of my staff informed your associate Lawrence Hufstedler in a telephone conversation, section S12 sets forth a detailed multi-step procedure for calculating a convex mirror's average radius of curvature. The first step is to take ten readings on the mirror surface with a 3-point linear spherometer as specified in Figure 1 of the Standard. (See S12.1.) The second step is to convert each of the ten readings to a 'radius of curvature calculation' using Table 1. (See S12.5.) The third step is to calculate the 'average radius of curvature' by adding all 10 radius of curvature calculations and dividing by 10. (See S12.6.) Mr. Hufstedler asked how S5.4.1 affects the calculations. That section states 'none of the radii of curvature readings shall deviate from the average radius of curvature by more than 12.5 percent.' This means that some of the radii of curvature readings may be up to 12.5 percent different than the average radius of curvature. In numerical terms, this means that if a mirror had an average radius of curvature of 36 inches a given radii of curvature reading could be as low as 31.5 inches and as high as 40.5. I hope this information is helpful. Please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam2655OpenMr. Paul J. Kelley, Assistant to the President, U-Haul International, 2727 North Central Avenue, Phoenix, AZ 85036; Mr. Paul J. Kelley Assistant to the President U-Haul International 2727 North Central Avenue Phoenix AZ 85036; Dear Mr. Kelley: This is in response to your letter of August 8, 1977, concerning th language in Title I of the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513) stating that 'to the maximum extent practicable, a bumper standard promulgated by the Secretary shall not preclude the attachment of detachable hitches.' In your letter you refer to correspondence dated May 5, 1976, on the same subject. I regret that due to an administrative oversight that letter was not answered.; In your letter you expressed your opinion that Congress intended i Title I to place an affirmative obligation on the National Highway Traffic Safety Administration (NHTSA) to ensure that vehicles are produced with bumpers that can accommodate detachable bumper hitches. The main support offered for your position is a comment by Congressman William Springer made at the time the conference bill was presented to the full House of Representatives. Mr. Springer's statement was that 'bumpers should be practicable and allow for the use of bumper hitches, that is, the hitches that you use to hook something else behind the automobile.' It appears that you have interpreted Mr. Springer's statement as indicating an intent that the bumper standard ultimately promulgated require that bumpers be designed to accommodate detachable bumper hitches.; Having reviewed the legislative history of Title I, I must disagre with your position. Congress was explicit in its direction that the agency express any bumper standard in minimum performance terms so as to allow the industry to make full use of its technological resources in devising a means of complying with the requirements. This mandate has been fulfilled by the agency. Part 581, *Bumper Standard*, provides that a vehicle be capable of meeting the specified damage criteria when involved in 5 mph impacts with a pendulum test device and a fixed barrier. Manufacturers are free to satisfy that performance level in whatever manner they choose. That manufacturing freedom would be compromised were the agency to require the production of vehicles with bumper systems suitable for detachable bumper hitches. Such a result would clearly be contrary to Congress' Title I directive.; With regard to the contracts with Calspan and Minicars, the vehicle developed under those programs are not required by law to satisfy a particular set of safety criteria. Under those contracts vehicles that meet high levels of safety, damage-resistibility, and fuel economy are to be developed. Accommodation of detachable bumper hitches is not a factor in any of those areas of concentration.; I want to assure you that the NHTSA shares your interest in providin the public with a means to tow. Our actions under Title I preserve the ability of manufacturers to produce bumper systems that continue to satisfy that public need.; Sincerely, Joan Claybrook |
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ID: aiam3697OpenTom Caine, Esq., Law Department, The Goodyear Tire & Rubber Company, Akron, OH 44316; Tom Caine Esq. Law Department The Goodyear Tire & Rubber Company Akron OH 44316; Dear Mr. Caine: This responds to your recent letter in which you asked for a interpretation concerning the status of tires which are manufactured by applying new tread to a new casing. Specifically, you ask whether such tires should be considered retreaded tires or new tires subject to the applicable Federal motor vehicle safety standard.; Any tires manufactured by applying new tread to new casings would b considered new tires rather than retreaded tires, and would be subject to the same requirements as any other new tires.; Standard No. 117, *Retreaded Pneumatic Tires* (49 CFR S 571.117) defines the term 'casing' as follows: 'Casing means a used tire to which additional tread may be attached for the purpose of retreading.' In the situation you described in your letter, the casing is not a used tire. It is simply a new tire which has never had any tread attached to it. That casing would not be considered a used tire until the casing and the new tread attached to it had been used on the highway and the remainder of the tread then buffed off the casing to allow the application of another new tread. Only then could the casing be considered a used tire. With the addition of the new tread, the used tire would become a retreaded one.; I would appreciate it if you would forward any factual information yo have about the proposed importing of new casings to this agency's Office of Vehicle Safety Compliance. This will help us ensure that all imported new casings with new treads attached to them are subjected to the new tire performance tests.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4152OpenStephen T. Waimey and Dean Hansell, Esqs., Donovan Leisure Newton & Irvine, 333 South Grand Avenue, Los Angeles, CA 90071; Stephen T. Waimey and Dean Hansell Esqs. Donovan Leisure Newton & Irvine 333 South Grand Avenue Los Angeles CA 90071; Dear Messrs. Waimey and Hansell: This responds to your letter asking two questions about Part 541 *Federal Motor Vehicle Theft Prevention Standard*. First, you asked if the 17-character vehicle identification number (VIN) required on original equipment engines and transmissions had to appear in a single line. You stated that your client would like to mark the engines and transmissions by splitting the VIN into two groups, with the second group of characters directly below the first. Such markings would comply with Part 541. Second, you asked if your client could use a trademark that was less than one centimeter high for marking replacement parts. Markings less than one centimeter high would not comply with the requirements of Part 541 applicable to replacement parts. These conclusions are explained in detail below.; If a vehicle manufacturer was not identifying its engines and/o transmissions with at least an 8- character VIN derivative as of October 24, 1984, S541.5(b)(1) requires the engine and transmission to be marked with the full 17-character VIN. That section does *not* require that the 17 characters appear on the same line. However, the preamble to the final rule establishing Part 541 explained the policy reasons for requiring the full 17-character VIN as follows:; << |
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ID: aiam2985OpenMs. Linda J. Hoffman, Automotive Parts & Accessories Association, 1025 Connecticut Avenue, N.W., Washington, D.C. 20036; Ms. Linda J. Hoffman Automotive Parts & Accessories Association 1025 Connecticut Avenue N.W. Washington D.C. 20036; Dear Ms. Hoffman: This responds to your March 5, 1979, letter concerning th applicability of Safety Standard No. 301-75, *Fuel Systems Integrity*, to replacement fuel tank caps. I am enclosing my letter of interpretation on this subject issued by the agency in 1976 which should answer all of your questions. If, however, you require further information, please contact Hugh Oates of my office at (202) 425-2992.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1350OpenMr. Patrick C. Ross, President, B.F. Goodrich Tire Company, 500 South Main Street, Akron, Ohio 44318; Mr. Patrick C. Ross President B.F. Goodrich Tire Company 500 South Main Street Akron Ohio 44318; Dear Mr. Ross: This is in reply to your petition, dated may 18, 1973, for amendment to Motor Vehicle Safety Standard No. 109 and the Tire Identification and Recordkeeping regulations (49 CFR Part 574). You request that the standard be amended to except tires having an 'unusual configuration and construction,' from the part of S4.3 which requires safety information to be labeled between each tire's maximum section width and bead. You request a similar exception in Part 574 for the tire identification number. Goodrich has experienced difficulties in placing this information in the proper location in tire molds used to manufacture Goodrich's Space Saver Spare tire. You indicate this is caused by the thinness of the mold, which is apparently necessitated by the folding sidewall characteristics of the tire.; In case of the Space Saver Spare, Goodrich wants to be able to plac the labeling information and the identification number in the shoulder area of the tire. Your request is supported with pictures of a Space Saver Spare that has been run to wear-out yet still retains legible labeling in this area. In your view it is unlikely that this tire will be retreaded. You argue that the location you desire to use, while not between the maximum section width and bead, has the advantage of making the information and identification number visible both when the tire is inflated and deflated. the latter condition is important in this case in that this tire is generally carried in a deflated, folded condition when it is not in use.; We do not believe the facts you present justify an amendment to th standard, and have therefore determined that your petition should be denied. The purpose of requiring safety information and the tire identification number to be placed between each tire's maximum section width and the bead is to ensure, to the greatest extent possible, that the information will remain on the tire throughout its useful life, including a retreading process if the tire is retreaded. In our View, it is not all clear that the alternative location you suggest will still meet this objective. The justification which you provide does not show that labeled information cannot be removed in service or that these tires will not, in fact, be retreaded. We certainly would not object if Goodrich were to place identifying information in separate location in addition to that required by the standard.; With respect to the difficulty you have encountered in placing th information in the specified area, we do not find on the basis of the information you have supplied that the alternative possibilities are impracticable. For example, your letter does not mention whether you have attempted to engrave the safety information and that part of the identification number that is constant into the tire molds. While we understand engraving is generally more expensive and somewhat more inconvenient than branding the mold or using metal plates, we do not believe the added expense and inconvenience, particularly as it is amortized over the life of the mold, to be unreasonable in terms of the safety benefit achieved. It also appears that this labeling, in letters 0.078 inches in height, can be placed just above the rim centering rib, which from the sample submitted with your petition, does not appear to have been damaged upon removal. This location would allow removal of the tire from the mold without deformation of the lettering and would place the required information between the tire's maximum section width and bead. With respect to date codes, for which engraving is unsuited, it appears that the code stamp could be recessed so as to be flush with the mold surface, thus eliminating or substantially reducing the destruction of the lettering during removal.; Sincerely, James B. Gregory, Administrator |
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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.