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: aiam1232OpenMr. Gino D'Angelo, Director of State Police, Fiscal Management, New York State Police, Albany, NY 12226; Mr. Gino D'Angelo Director of State Police Fiscal Management New York State Police Albany NY 12226; Dear Mr. D'Angelo: This is in reply to your letter on August 20, 1973, asking that la enforcement vehicles be excluded from a Federal prohibition against headlight flashers.; There is no such prohibition. While paragraph S4.6(b) of Federal Moto Vehicle Safety Standard No. 108 requires headlamps to be steady-burning in use, it also specifically states that 'means may be provided to flash [automatically] headlamps . . . for signalling purposes.' Therefore, manufacturers are not prohibited from equipping vehicles with headlamp flasher units upon customer request.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4460OpenRobert J. Kaufman, Esq. Gingold, Kaufman & Chaiken 400 Perimeter Center Terrace, N.E. Suite 720 Atlanta, GA 30346-1234; Robert J. Kaufman Esq. Gingold Kaufman & Chaiken 400 Perimeter Center Terrace N.E. Suite 720 Atlanta GA 30346-1234; Re: GK&C File "1012-271 Dear Mr. Kaufman: This responds to your recent lette concerning the advice I gave to a company called Auto Accessories, Inc., with respect to the installation of that company's armrests in Volvo 240 automobiles. More specifically, on behalf of your client, a Volvo dealership, you seek clarification of that advice and request copies of any information, e.g., tests or studies, regarding the armrests. I appreciate your client's concern for safety. For your information, I have enclosed a copy of my November 18, 1987 letter to that company, in which the advice was provided. I have also enclosed a copy of the armrest installation instructions that were proposed by Auto Accessories and discussed in my response. Based on your reading of a letter from Auto Accessories to Volvo dealers (enclosed with your letter), you concluded that the armrest installation procedure 'ostensibly was either approved, mandated, or suggested by the Department of Transportation.' As you will see from my November 1987 letter, the Department did not take any of those actions. This Department has no authority under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) to approve or endorse any items of motor vehicle equipment or installation procedures therefor. Instead, the Safety Act puts the responsibility on manufacturers to certify that their products comply with the applicable requirements (15 U.S.C. 1403), and obliges manufacturers, distributors, dealers, and motor vehicle repair businesses not to knowingly render inoperative any devices or elements of design in vehicles that were installed in compliance with applicable safety standards (15 U.S.C. 1397(a)(2)(A)). In keeping with this statutory scheme, this agency did not make a determination in the November 1987 letter or on any other occasion that a dealer following the proposed installation instructions would or would not render inoperative a vehicle's compliance with the safety standards. The agency makes such determinations only in the context of an enforcement proceeding. Instead, my November 18 letter pointed out the element of design that might be rendered inoperative by installing the armrests, and advised Auto Accessories as the manufacturer to carefully examine its instructions to determine whether or not following them would result in a 'render inoperative' violation. It appears from the Auto Accessories letter to dealers that that company believes the installation of its armrest would not result in any violations. Our advice to dealers is essentially the same as the advice we gave to Auto Accessories. Dealers should examine the instructions to determine whether following them would render inoperative a vehicle's compliance with Standard No. 208 or any other standard. You may wish to contact Auto Accessories to learn more about the basis for its apparent belief that the installation of its armrest will not violate any requirements of the Safety Act. As for the tests and studies you requested, again, because of our statutory scheme, we have not conducted any regarding the armrest or its installation. We would do so only in the context of an enforcement proceeding. Please let me know if you have any further questions on this subject. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam1398OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Assoc., 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Assoc. 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in response to your letter of January 30, 1974, requestin information concerning whether or not a certification label is required to be furnished by one who installs a snow plow on a completed vehicle prior to the first purchase of the vehicle for purposes other than resale.; An additional certification label is required when a vehicle is altere by the addition of parts that are not readily attachable components. Whether or not the snow plow is a readily attachable item depends in large part on the manufacturer's intent in designing the vehicle.; If the addition of the snow plow necessitated a change in the weigh ratings of the vehicle, there would be an obligation of the alterer's part to attach an additional certification label in accordance with 49 CFR 567.7.; Thank you for your inquiry. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1662OpenMr. Charles J. Calvin, President, Truck Trailer Manufacturers Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Charles J. Calvin President Truck Trailer Manufacturers Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Calvin: This responds to your October 23, 1974, question in behalf of Steadma Containers, Ltd., asking if Standard No. 121, *Air brake systems*, applies to the Steadman 'liftainer', which is described as a semi-trailer frame capable of carrying 20- and 40-foot cargo containers that are loaded by means of cranes mounted at each end of the semi-trailer. The vehicle is used to move containers in terminal areas and is used on the highway only in relocation to another terminal.; The 'liftainer' is a motor vehicle as that term is defined in th National Traffic and Motor Vehicle Safety Act of 1966, because it uses the highway on a necessary and recurring basis to move between work sites. A discussion of the motor vehicle definition is enclosed for your information. As a motor vehicle, it is subject to the requirements of Standard No. 121 for trailers, effective January 1, 1975.; I have also enclosed a discussion of Standard No. 121's applicabilit to vehicles purchased by Canadians for use between Canadian and United States points. The standard would apply to Steadman trailers if they are purchased for use on U.S. highways.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0970OpenMr. Bernard W. Weber, Executive Vice President, Wesbar Corporation, Box 577, West Bend, WI 53095; Mr. Bernard W. Weber Executive Vice President Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Weber: This is in reply to your letter of January 3, 1973, to Mr. Schneide concerning Motor Vehicle Safety Standard No. 108.; Your first question is whether the standard requires items of lightin equipment to be marked according to SAE Standard J759a. The answer is no. A manufacturer, at his option, may mark equipment items with the symbol DOT as a certification of compliance with Standard No. 108. Standard No. 108 neither prohibits nor requires other marking of equipment. The NHTSA proposed in 1972 that equipment be marked in a manner somewhat similar to J759a but no definitive action has been taken on the proposal.; You also asked whether a clearance lamp could be mounted at 45 degree to serve the functions of both a clearance and side marker lamp, and whether it must bear the SAE designation 'PC' indicating its combination function. Your understanding is correct, that a combination lamp mounted at 45 degrees is permissible if it is successfully tested at that mounting angle for conformance to both clearance and side marker requirements. The designation 'PC' is not a current requirement of Standard No. 108 but has been proposed as the required marking symbol in the rulemaking action referred to earlier.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2268OpenHonorable Herman E. Talmadge, Chairman, Committee on Agriculture and Forestry, United States Senate, Washington, DC 20590; Honorable Herman E. Talmadge Chairman Committee on Agriculture and Forestry United States Senate Washington DC 20590; Dear Mr. Chairman: This is in response to your letter of April 1, 1976, forwardin correspondence from Mr. James A. Graham concerning the recently issued Part 581 bumper standard.; On March 4, 1976, the National Highway Traffic Safety Administratio (NHTSA) published a Federal bumper standard (41 FR 9346, 49 CFR Part 581) under the authority of Title I of the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513). The standard, effective September 1, 1978, specifies limitations on damage to non-safety related as well as safety-related vehicle components in low-speed collisions. Several manufacturers, including Gulf and Western Manufacturing Company, have filed petitions for reconsideration of the standard in conformance with NHTSA rulemaking procedures (49 CFR 553.35).; It is NHTSA's policy to issue a notice of action taken on petitions fo reconsideration within 120 days after publication of the final rule, unless action within that time is impracticable. Since the agency is currently in the process of considering the petitions received, it would not be appropriate for us to comment at this time on the remarks made by Mr. Graham in his letter.; I assure you that Mr. Graham's comments and the information containe in all of the petitions for reconsideration will receive thorough consideration. The agency's response to the petitions will be published in the *Federal Register*.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0255OpenIng. Andrea Catanzano, Automobili Lamborghini, 40019 S. Agata Bolognese (Bologna), Italio; Ing. Andrea Catanzano Automobili Lamborghini 40019 S. Agata Bolognese (Bologna) Italio; Dear Dr. Catanzano: Thank you for your letter of September 23 informing us of lamborghini' continue progress towards compliance with Federal motor vehicle safety standards.; I want to remind you that Standard No.. 211 precludes the use of whee nuts, wheel discs, and hub caps that incorporate winged projections, such as the one shown in the Espada photograph which I enclose. We have seen several Espadas manufactured in 1969 with wheels identical to this one, and were informed in one instance that the winged projections had been shipped form Italy with the car. Such a shipment violates the spirit, if not the letter of Standard No. 211.; There is no charge for the 'Program Plan for Motor Vehicle Safet Standards', enclosed at your request.; Sincerely, Lawrence R. Schneider, Acting Deputy Chief Counsel |
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ID: aiam2792OpenMr. R. G. Wilkins, Product Safety and Reliability, Grove Manufacturing Co., Shady Grove, PA 17256; Mr. R. G. Wilkins Product Safety and Reliability Grove Manufacturing Co. Shady Grove PA 17256; Dear Mr. Wilkins: This responds to your recent letter asking whether plastic glazin materials may be used on the superstructure operator cabs of mobile construction cranes. Apparently, the upper superstructure cab is used only for craning operations and is distinct from the cab used to drive the crane over public highways.; Under Federal Motor Vehicle Safety Standard No. 205, *Glazin Materials* (49 CFR Part 571.205), plastic glazing may be used only in locations to the rear of the driver in trucks or truck tractor cabs and only at levels not requisite for driving visibility. Therefore, plastic glazing could not be used in the windshield or windows to the right or left of the driver in the main driving cab of the mobile crane. It is our interpretation, however, that the superstructure operator cab is, effectively, to the rear of the driver when the vehicle is being used on the highway and could be equipped with plastic glazing materials meeting the requirements of Standard No. 205. This interpretation assumes that the operator cab cannot be used to drive the mobile crane on the highway. If the operator cab could be used as the driving cab, plastic glazing could only be used in locations to the rear of the driver at levels not requisite for driving visibility.; Please contact this office if you have any questions concerning thi interpretation.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5057OpenThe Honorable Dave Durenberger United States Senate 1020 Plymouth Building 12 S. 6th Street Minneapolis, MN 55402; The Honorable Dave Durenberger United States Senate 1020 Plymouth Building 12 S. 6th Street Minneapolis MN 55402; "Dear Senator Durenberger: Thank you for your letter on behalf of you constituent, Mr. Mark Gassert, regarding the installation of the Drivemaster One-Arm-Drive hand control system in a van. I am pleased to have this chance to provide you the following information. Section 103 of the National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1392) authorizes NHTSA to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and new items of motor vehicle equipment. Manufacturers are required to certify that their products meet all applicable safety standards. NHTSA periodically tests certified products to ensure that they do, in fact, comply with applicable standards, and investigates allegations that products contain defects related to motor vehicle safety. If a new vehicle were altered by installation of adaptive controls prior to the vehicle's first sale to a consumer, the person making the installation would be considered an 'alterer' and would be required by 49 CFR Part 567, Certification, to certify that the vehicle continues to comply with all applicable safety standards affected by the alteration. Based upon the information in Mr. Gassert's letter, it appears that requirements for new light trucks and vans in Standard No. 208, Occupant Crash Protection, which were upgraded as of September 1, 1991, may be preventing him from purchasing a new van with a hand control system. Light trucks and vans manufactured on or after that date must be capable of providing occupant crash protection to belted front seat occupants when the vehicle is crash tested at 30 miles per hour (mph) into a concrete barrier. A vehicle that provides this crash protection will increase the safety of vehicle occupants. As a result of this new requirement, this agency has recently received a number of phone calls and letters, from van converters and individuals, suggesting that the new light truck and van crash testing requirement will, in effect, prohibit van converters from modifying vehicles to accommodate the special needs of persons in wheelchairs. The agency has also received a petition from the Recreation Vehicle Industry Association (RVIA) requesting an amendment to the light truck and van crash test requirement 'to eliminate requirements that inadvertently discriminate against individuals with disabilities including individuals who use wheelchairs.' On January 9, 1992, the agency granted the RVIA petition. On August 5, 1992, the agency issued a notice of proposed rulemaking (NPRM) to amend the requirements of Standard No. 208 to give manufacturers of certain light trucks and vans the option of installing non-dynamically tested manual safety belts instead of complying with the dynamic testing requirements. I have enclosed a copy of the NPRM with this letter. Because of the importance of this subject, the agency has decided it is more appropriate to address it comprehensively, in the context of a rulemaking, instead of in a piecemeal fashion, in response to letters presenting individual cases and individual aspects of the subject. By addressing this subject comprehensively, NHTSA will be able to ensure that the resulting requirement offers persons in wheelchairs the best possible safety protection. However, the agency is aware that Mr. Gassert and others who need to purchase a new vehicle need more immediate relief than a rulemaking can offer. Therefore, as explained in the NPRM, the agency has stated that it will not conduct any dynamic testing under Standard No. 208 of vehicles modified for operation by persons with disabilities while this rulemaking is pending. This should allow Mr. Gassert and others to purchase a new vehicle while this decision is pending. I hope you find this information helpful. If you have any other questions, please feel free to contact me at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam3880OpenMr. H. Tsujishita, Daihatsu Motor Co., Ltd., No.7,2-Chome, NIHONBASHI-HONCHO, Chuo-ku, Tokyo, Japan; Mr. H. Tsujishita Daihatsu Motor Co. Ltd. No.7 2-Chome NIHONBASHI-HONCHO Chuo-ku Tokyo Japan; Dear Mr. Tsujishita: This responds to your letter of November 26, 1984, requesting severa interpretations of Standard Nos. 201, 208, and 210. The answers to your questions raised in Attachments I, II, and III of your letter are discussed below.; In attachment I of your letter, you asked about the requirement o S3.5.1(c) of Standard No. 201. You were specifically concerned about the language which provides that the length of the armrest is to be measured vertically in side elevation. You provided a drawing of an armrest and asked if the length is to be measured as shown in section (dimension) b of your Figure 1.; The purpose of the requirement is to ensure that there is at last inches of coverage within the pelvic impact area. For this requirement to be meaningful, the covered surface must be contactable by the vehicle occupant. The vehicle occupant would not contact the base of the arm rest illustrated in your drawing. Therefore, the measurement should be made at dimension a in section A-A or dimension c in section B-B as shown in your Figure 1.; On question one of Attachment II, you asked about the application o Standard Nos. 208 and 209 to a safety belt system you are developing to meet S4.1.2.1 of Standard No. 208. The system consists of a two point automatic belt and a Type 1 manual safety belt. You asked which requirements of Standard No. 209 apply to such an automatic belt. I have enclosed an interpretation letter of August 7, 1981 to Volkswagen which explains the application of Standard No. 209 to an automatic belt.; In question two of Attachment II, you state that your vehicle will hav four anchorages for each front outboard seating position (two anchorages for the automatic belt and two for the Type 1 seat belt assembly). You said that S4.4.1 of Standard No. 210 requires seat belt anchorages for Type 2 safety belts at each front outboard seating position and you asked what is meant by anchorages for a Type 2 belt. You also asked whether you must install any other anchorages at those positions in your vehicle.; Paragraph S4.1.1. of Standard No. 210 requires anchorages for a Type seat belt assembly to be installed for each forward-facing outboard designated seating position in passenger cars. This is true regardless of whether the seating position is equipped with an air bag and a lap belt, with a single diagonal automatic belt or with any other system. Safety Standard No. 210 is independent of Safety Standard No. 208, *Occupant Crash Protection*. A Type 2 belt requires three anchorages (two for the lap portion of the belt and one for the upper torso restraint). The presence of the Type 2 anchorages in vehicles will allow vehicle owners to install easily Type 2 belts at their own initiative if they desire to do so for whatever reason. For example, if a single diagonal automatic belt system has been damaged, an owner may wish to replace it with a Type 2 manual belt system.; Under paragraph S4.3 of Safety Standard No. 210, anchorages fo automatic belts are exempted from the location requirements of the standard. This exception was provided for in the standard to allow manufacturers to experiment with various automatic belt designs to determine the optimum anchorage locations in terms of both effectiveness and comfort (43 FR 53440, Nov. 16, 1978). If, however, anchorage points for an automatic belt do not fall within the location specified in the standard for Type 2 belts, the manufacturer would have to provide additional anchorage points that could be used by a properly located Type 2 manual belt. Thus if your lap belt and upper torso anchorages fall within the location requirements for Type II belts, you would not have to provide any additional anchorages.; In question three of Attachment II, you asked what strength tes applies to anchorages used with an automatic belt and to the manual lap belt used in your system. You illustrated the test procedures you plan to use in your Figure 3. As explained below, the procedure shown in Figure 3(1) is correct and the procedure shown in Figure 3(2) is partially correct.; The agency has stated in an interpretation letter of July 23, 1980 t Mazda that the anchorages for a single diagonal automatic belt should be tested with a 3,000-pound force for purposes of Standard No. 210, in accordance with the test procedures of paragraph S5.2. This is the same force that is required for testing the upper torso portion of a Type 2 seat belt system. This force requirement is applicable whether the single diagonal automatic belt is used alone or whether it is used in conjunction with a manual lap belt. The anchorages for the manual lap belt, however, would be required to withstand test forces of 5,000 pounds under paragraph S4.2.1 for Standard No. 210. The anchorages for the manual lap belt and for the automatic belt must separately meet their respective force requirements and would not have to be tested simultaneously since they are separate systems.; In question one of the Attachment III, you requested the agency t clarify the words 'fold' and 'tumble' used in S7.4.6 of Standard No. 208. You stated your understanding that 'fold' means to move the seat back forward as shown in your Figure 4-a and 'tumble' means to move both the seat cushion and seat back forward as shown in your Figure 4-b. Your understanding of both words is correct.; In question two of Attachment III, you asked the meaning of the wor 'receptacle' as used in paragraph S7.4.6.2 of Standard No. 208. The word 'receptacle' refers to the devices into which an occupant would insert the tang of a safety belt to fasten the belt.; I hope this satisfactorily answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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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.