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: aiam1696OpenMr. Harold Dvorachek,Product Engineer,The Berg Manufacturing Company,333 East Touhy Avenue,Des Plaines, Illinois 60018; Mr. Harold Dvorachek Product Engineer The Berg Manufacturing Company 333 East Touhy Avenue Des Plaines Illinois 60018; Dear Mr. Dvorachek:#This responds to your letter of October 25, 1974 requesting an interpretation of Standard No. 106-74, *Brake hoses*, as it applies to the labeling of air brake hose end fittings which use sacrificial sleeves.#>>>S7.2 states:#In the case of an end fitting intended for use in a reuseable assembly, 'AI' or 'AII' shall indicate use with Type I or type II hose respectively.<<<#Since an end fitting which uses a sacrificial sleeve is defined by S4 to be a permanently attached end fitting, it does not fall into the classification 'End fitting[s] intended for use in a reuseable assembly.' Therefore, it must be labeled with the designation 'A' rather than any of the following: 'AI', 'AII', 'AI-AII'.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam2813OpenMr. E. M. Ryan, Chief Design Engineer, Ward Industries, Inc., P.O. Box 849, Highway 65 South, Conway, AR 72032; Mr. E. M. Ryan Chief Design Engineer Ward Industries Inc. P.O. Box 849 Highway 65 South Conway AR 72032; Dear Mr. Ryan: This responds to your April 27, 1978, letter asking whether a sampl certification label that you submitted complies with the National Highway Traffic Safety Administration's (NHTSA) Part 567, *Certification*.; Military vehicles are exempted from compliance with Federal safet standards. Therefore, the application of the safety standards to these vehicles is a matter of contract between a manufacturer and the military. Since the NHTSA does not mandate Federal safety standards for these vehicles, it is not necessary to put certification labels on them. If you choose to include a label with a vehicle, the label would not be required to comply with any Federal regulations.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3701OpenMr. Alberto Negro, Fiat Research & Development - USA Branch, Fiat Motors of North America, Inc., Parklane Towers West, Suite 1210, Dearborn, MI 48126; Mr. Alberto Negro Fiat Research & Development - USA Branch Fiat Motors of North America Inc. Parklane Towers West Suite 1210 Dearborn MI 48126; Dear Mr. Negro: This is in reply to your letter of May 9, 1983, to Mr. Vinson of m staff with respect to conformance of a planned stop lamp design with Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*.; The design comprises two compartments separated by a reflex reflector One of the compartments will meet the photometric requirements for a stop lamp, in your judgment. The other will not, but in conjunction with the first compartment 'the requirements can be met.' You have asked if this arrangement is acceptable pursuant to paragraph S4.1.1.6 which allows photometric requirements to be met by a combination of compartments or lamps.; Paragraph S4.1.1.6 is intended to cover replacement stop lamps fo vehicles manufactured between January 1, 1973, and September 1, 1978, when the SAE standard for stop lamps incorporated into Standard No. 108 was SAE J586b, September 1966. As such, its requirements are not relevant to your concerns.; However, SAE J586c, August 1970, whose requirements do apply to sto lamps, appears to permit your design. Under paragraph 3.1, where the distance between filament centers of two stop lamps does not exceed 22 inches (presumably your design) the photometric readings of both lamps must be combined to meet the photometric requirements of Table 1 of J586c applicable to two lighted sections. However, the combined candela must not exceed the specified total of 360 for two lighted sections.; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4210OpenMr. Eric E. Gough, Manager, Corporate Technical Affairs, Lucas Industries, Inc., P.O. Box 7002, Troy, MI 48007-7002; Mr. Eric E. Gough Manager Corporate Technical Affairs Lucas Industries Inc. P.O. Box 7002 Troy MI 48007-7002; Dear Mr. Gough: This is in reply to your letter of August 19, 1986, to this Office asking for confirmation of your understanding 'that other light sources can be added to a replaceable bulb headlamp, such as a parking lamp or signal lamp function, as long as the lamps operate independently of each other and are in full compliance with FMVSS 108.'; Your interpretation is essentially correct, and I am enclosing a cop of a recent letter that we sent to Ichikoh Industries on the same subject. In order to be in full compliance with Standard No. 108, if a replaceable bulb headlamp also incorporates a turn signal lamp, the requisite separation distance or candela ratio specified by the standard must be met.; I hope that this answers your question. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1012OpenMr. John H. Fildew, Attorney, Fildew, Gilbridge, Miller & Todd, 3156 Penobscot Building, Detroit, MI 48226; Mr. John H. Fildew Attorney Fildew Gilbridge Miller & Todd 3156 Penobscot Building Detroit MI 48226; Dear Mr. Fildew: This is in response to your letter of February 14, 1973, in which yo asked about the responsibilities with respect to the motor vehicle safety standards of an automobile dealer who sends a new vehicle to specialty manufacturer for modifications. You asked whether the dealer must file reports as a final-stage manufacturer, or ascertain whether the specialty manufacturer has filed reports or certified the vehicle.; The final-stage manufacturer in the case you describe is the specialt manufacturer, and all the responsibilities that pertain to that category lie with him, not the dealer. There is also no obligation for the dealer to ascertain that the specialty manufacturer has filed reports.; The answer with respect to the dealer ascertaining that the final stage manufacturer has certified the vehicle is somewhat less clear. There is no direct responsibility for this, a failure of the final-stage manufacturer to certify would not itself bring down any penalties on the dealer. However, the certification is designed to protect the dealer, in cases of nonconformity with the standards of which the dealer does not have actual knowledge. (See sections 108(b)(2) and 114 of the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1397(b)(2), 1403.) To put it negatively, if the vehicle were completed in violation of applicable standards and it were not certified, a dealer might be considered to have sold a nonconforming vehicle without the exercise of due care, in violation of the Act. The question is further complicated by the fact that not all alterations would rise to the level of manufacturing (addition of trailer hitches probably would not, for example). and these minor changes would not require additional certification by anyone. In sum, although there is no direct legal obligation for the dealer to see that there is a certification where there are major alternations, it is a very good idea, for his own protection.; The regulations on this subject are codified in Parts 567 and 568 o Title 49, Code of Federal Regulations. The October 1, 1972 edition of that title is current with respect to those parts. We do have a proposal outstanding to make some amendments regarding the certification of altered vehicles (37 FR 22800, October 25, 1972), and an amended rule may be issued in the near future.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4640OpenMr. Bernie Cantleberry 5958 Maplewood Road Mayfield Heights, Ohio 44l24; Mr. Bernie Cantleberry 5958 Maplewood Road Mayfield Heights Ohio 44l24; "Dear Mr. Cantleberry: This responds to your letter concerning Safet Standard No. l05, Hydraulic Brake Systems. You asked several questions about the standard's requirements for parking brakes. Your questions are addressed below. By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with applicable standards. The following represents our opinion based on the facts provided in your letter. Your first question concerns section S5.2. That section requires specified vehicles to be 'manufactured with a parking brake system of a friction type with a solely mechanical means to retain engagement . . . .' You asked what is meant by a 'parking brake system of a friction type with a mechanical means.' In understanding section S5.2, I believe it is helpful to focus on three aspects of the language quoted above. First, a vehicle must be 'manufactured with a parking brake system.' The term 'parking brake' is defined in 49 CFR Part 57l.3 as 'a mechanism designed to prevent the movement of a stationary motor vehicle.' Second, the required parking brake system must be 'of a friction type,' i.e., it must prevent the movement of a stationary motor vehicle by means of friction. For example, a parking brake which presses a brake shoe against a brake drum operates by friction, whereas the parking pawl of an automatic transmission does not. Third, the required parking brake system must have a 'solely mechanical means to retain engagement.' Thus, the parking brake cannot be held by non-mechanical means such as fluid, air or electricity. Your second question concerns section S5.2.2. You asked whether it is necessary to meet S5.2.2.l, S5.2.2.2, and S5.2.2.3 (i.e., all three subsections) in order to comply with section S5.2.2, or just one of the subsections. Section S5.2.2 provides that '(a) vehicle of a type described in S5.2.l at the option of the manufacturer may meet the requirements of S5.2.2.l, S5.2.2.2, and S5.2.2.3 instead of the requirements of S5.2.l,' if the vehicle has a transmission or transmission control which incorporates a parking mechanism, and the parking mechanism must be engaged before the ignition key can be removed. (Emphasis added.) Given section S5.2.2's use of the word 'and' (as highlighted above), it is necessary to meet the requirements of all three subsections in order to comply with that section's compliance option. You also asked whether a vehicle which has a parking control in the transmission must also have a hand or foot operated control for the brake system. In responding to this question, I assume that the term 'parking control in the transmission' refers to a parking pawl. As noted above, a vehicle manufactured with a parking pawl alone, without an additional parking brake, would not meet section S5.2's requirement that the vehicle be 'manufactured with a parking brake system of a friction type with a solely mechanical means to retain engagement . . . .' Thus, a vehicle which has a parking control in the transmission must also have an additional parking brake 'of a friction type with a solely mechanical means to retain engagement. . . .' Finally, you asked whether a vehicle with a hydraulic locking system would be sufficient to meet the requirements specified in S5.2.2. This question was asked both for a vehicle that has a parking control in the transmission and for a vehicle with a manual transmission. The requirement that a vehicle be 'manufactured with a parking brake system of a friction type with a solely mechanical means to retain engagement' cannot be met by a hydraulic locking system, since such the parking brakes on such a system are held by fluid pressure rather than by 'a solely mechanical means.' Thus, regardless of whether a vehicle has a parking pawl or has a manual transmission, a hydraulic locking system cannot be used to meet Standard No. l05's parking brake requirements. I hope that this answers your questions. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam3185OpenMr. Jeffrey Libman, President, Edison Rubber Company, P. O. Box 254, Edison, New Jersey 08817; Mr. Jeffrey Libman President Edison Rubber Company P. O. Box 254 Edison New Jersey 08817; Dear Mr. Libman: This responds to your letter of November 9, 1979, inquiring if it i permissible for your suppliers to cut off the DOT serial numbers on used tires before selling those tires to your company. You stated in your letter that your company buys used tires from several companies. These tires generally either have cuts in the tread or sidewalls or are out of round. Your company then resells the tires to another company, which resells the tires to the public.; The answer to your question is no. The presence of the DO identification number on tires is required by several of this agency's regulation. Our tire identification and record keeping regulation (49 CFR Part 574) requires that each manufacturer place the DOT number on at least one sidewall of each tire that it manufactures. The number serves several purposes. It is indispensable in aiding consumers to identify tires subject to a recall campaign for safety defects and noncompliance with the safety standards. It also aids this agency in enforcing its tire safety standards. Federal Motor Vehicle Safety Standards 109 (Passenger car tries, 49 CFR 571.119) and 119 (Tires for vehicles other than passenger cars, 49 CFR 571.119) require that each tire manufacturer certify that its tires conform to all applicable Federal safety standards by branding or molding the DOT number on the tire.; Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safet Act of 1966, as amended (15 U.S.C. 1397(a)(2)(A)), states that, 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on... an item of motor vehicle equipment in compliance with an applicable federal motor vehicle safety standard ....' By removing the DOT identification number from a tire, the person would be knowingly rendering inoperative an element of design on the tires which is included on the tire for compliance with the requirements of a Federal motor vehicle safety standard. Section 109 of the Act (15 U.S.C. 1398) specifies a penalty of up to $1,000 for each violation of section 108.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1442OpenHonorable Frank Thompson, Jr., House of Representatives, Washington, DC 20515; Honorable Frank Thompson Jr. House of Representatives Washington DC 20515; Dear Mr. Thompson: This responds to your March 19, 1974, request for information in behal of Mr. Robert J. Jones, concerning the commercial offer he received for a device that would defeat the ignition interlock device found on 1974 model passenger cars.; The National Traffic and Motor Vehicle Safety Act of 1966 authorize the issuance of motor vehicle safety standards, one of which requires occupant crash protection, one aspect of which is the ignition interlock system. Section 108(a)(1) of the Act prohibits the sale, offer for sale, introduction into interstate commerce, or the importation of any motor vehicle which does not conform to the standards. Our regulatory authority over new vehicles ends, however, with the first purchase of the vehicle in good faith for purposes other than resale. While we can prohibit arrangements between a dealer and a purchaser to disconnect the interlock, where they are part of the sales transaction, we have no remedy against arrangements to defeat the safety features made after the sales transaction.; Nevertheless, while selling devices intended to defeat safety equipmen may be legal, we consider such practices reprehensible since they increase the chances of death and injury on the highways. We are considering a variety of remedies for the situation reported by Mr. Jones.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam5401OpenMr. R. H. Goble President, Goble Enterprises P.O. Box 423 Lake Mary, FL 32795; Mr. R. H. Goble President Goble Enterprises P.O. Box 423 Lake Mary FL 32795; "Dear Mr. Goble: This is in reply to your letter of May 16, 1994, wit respect to two motor vehicle lighting systems that you have developed, and your question about the regulations that may apply to each. As we understand the first system, when the brake pedal is applied, the front turn signal lamps and front side marker lamps are simultaneously activated to indicate to observers from the front and side that the vehicle is braking. It appears that this activation is in a steady burning state which continues unless and until the turn signal lamps are activated in either the flashing turn signal or hazard warning signal more. You have also developed a 'Wheel Well lighting system', which 'will provide light indicators all around (brake, clearance, turn signal, emergency flashers)' through amber lamps mounted in the well at the top of each front and rear wheel opening. As we understand this system, these supplementary lamps will be activated simultaneously when the four named lamp systems are activated. The regulation governing the lighting on new motor vehicles (i.e., requirements that must be met when a new vehicle is delivered to its first purchaser) is Federal Motor Vehicle Safety Standard No. 108. With respect to optional equipment such as your systems, Standard No. 108 allows each, provided that each does not impair the effectiveness of the lighting equipment required by the standard. The law governing the lighting on motor vehicles after their first sale is the National Traffic and Motor Vehicle Safety Act. In essence, it allows installation of each of your systems by a manufacturer, dealer, distributor, or motor vehicle repair business as long as the system does not 'knowingly render inoperative, in whole or part, any device or element of design installed in accordance with' Standard No. 108. We regard any supplemental lighting system with the potential of creating confusion in the eye of the beholder as one that impairs the effectiveness of other lamps on the vehicle, and one that renders inoperative, in part at least, other lamps by compromising their effectiveness. This is especially true when existing vehicle lamps are used to convey messages that are different from the purpose of those lamps. We believe it especially important to motor vehicle safety that signal lamps convey their message unmistakably and without ambiguity. We see no real problem that might be occasioned by the activation of the front turn signal lamps in a steady burning mode, although this might cause initial puzzlement in the eye of an oncoming driver unfamiliar with the system. While confusion is more likely when the turn signal is operating on one side while the other side remains steady burning, we believe that the flashing of the turn signal will continue to be interpreted as an intention to turn. Of course, when the hazard warning system is activated and completely overrides the steady burning front stop lamp, there would be no confusion as to signal message. Therefore, in our opinion, Federal law permits use of your front stop lamp system. Your second system does not operate through existing vehicle lamps but consists of additional lamps mounted in the wheel wells. These lamps would appear not to have the potential of confusion since they supplement existing lamps and operate in conjunction with them to convey the same message. Thus, Federal law, in our view, does not preclude use of your second system either. However, even if a supplementary lighting system is permissible under Federal law, it is subject to regulation by any State in which it is operated. We are not able to advise you with respect to State law, and suggest that you write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0603OpenMr. G. Utsunomiya, Liaison Engineer, Chief, Toyo Kogyo Co., Ltd., 3841 Mystic Valley Drive, Bloomfield Hills, MI, 48013; Mr. G. Utsunomiya Liaison Engineer Chief Toyo Kogyo Co. Ltd. 3841 Mystic Valley Drive Bloomfield Hills MI 48013; Dear Mr. Utsunomiya: This is in reply to your letter of January 28, 1972, in which you lis specific interior components and ask whether they are required to comply with Standard No. 302, 'Flammability of Interior Materials.' You state that these components are not designed to be energy absorbing in some vehicles.; With regard to the parcel shelf and scarf plate, as we indicated to yo in our letter of September 24, 1971, these components appear to closely resemble or to be merely different descriptions of items that are enumerated in S4.1 of Standard No. 302. If so, they must comply with the requirements. We also mentioned to you in that latter than seaming welt and seaming rubber should be considered as part of the component to which it is attached, and for which it provides a seam.; With regard to the other items you list, you should consider th language of S4.1 that reads, '. . . other interior materials . . . designed to absorb energy on contact by occupants in the event of a crash.' If in fact, as you indicate, these components are not so designed, then they need not meet the requirements of the standard. I would add that NHTSA is presently reviewing this requirement, and it may be modified in the near future.; 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.