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: aiam0528OpenMr. Satoshi Nishibori, Engineering Representative, Liaison Office In U.S.A., Nissan Motor Company, Ltd., 400 County Avenue, Secaucus, NJ 07094; Mr. Satoshi Nishibori Engineering Representative Liaison Office In U.S.A. Nissan Motor Company Ltd. 400 County Avenue Secaucus NJ 07094; Dear Mr. Nishibori: By letter of December 6, 1971, you have asked our opinion as to ho S6.1 of Standard 208 applies to two hypothetical situations. S6.1 requires that 'all portions of the test device shall be contained within the outer surfaces of the passenger compartment throughout the test.'; Your first situation involves a vehicle in which the impact of th dummy's head causes the windshield to bulge beyond its original location but does not penetrate the windshield. It is our opinion that in this case the vehicle has contained the occupant and would conform to S6.1.; In your second situation, the dummy's head pushes the windshield loos at its base and opens a gap between the windshield and the vehicle. It is our opinion that this drawing also shows the dummy to be satisfactorily contained.; In either situation, however, a manufacturer would have to assur himself that the windshield behavior shown in the drawings would be consistent and would not lead to failure in tests in which the test dummy strikes it in a different manner.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2515OpenMr. B. R. Weber, Executive Vice President, Wesbar Corporation, Box 577, West Bend, WI 53095; Mr. B. R. Weber Executive Vice President Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Weber: Thank you for your frank letter of January 13, 1977, commenting upo the lack of clarity you feel exists in my letter to you of December 6, 1976, interpreting Motor Vehicle Safety Standard No. 108.; As a lawyer it is obvious to me that the best regulatory practice is t be as specific as possible in establishing requirements and prohibitions. When a regulation itself is unclear, however, its interpretation may necessarily be imprecise. Because the term 'optical combination' in S4.4.1 is not defined, my answers were necessarily worded in general terms though with the thought of establishing a general framework of guidance for you. They were not intended to be 'a masterpiece of bureaucratic weasel words.' My letter meant, in plain English, that where tail lamps and clearance lamps are in a single compartment we don't want one lamp to perform, or to be perceived as performing, the function of the other. It is evident from your letter and others that our previous interpretations of the term 'optical combination' have been found to be ambiguous and lacking in the objective criteria that a Federal motor vehicle safety standard must provide. We have reviewed the matter, and now wish to modify our previous interpretation. In our view a lamp is 'optically combined' when the same light source (i.e. bulb) and the same lens area fulfill two or more functions (*e.g.* taillamp and stop lamp, clearance lamp and turn signal lamp). A dual filament bulb would be regarded as the 'same light source'. In determining conformance, the photometric requirements for clearance and taillamp functions, where two bulbs are located in a single compartment, must be met with only the bulb energized that is designed to perform the specific function. But the 15 candlepower maximum under Standard No. 108, however, would be determined with both the taillamp and clearance lamp bulb energized. Further, the lamp must be located to meet requirements for both clearance and taillamps. Our re- interpretation means that the issue of light spill-over from one area of the lamp to another is irrelevant to conformance.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1293OpenL.E. Haight, Esq., Attorney at Law, 805 Idaho Street, P.O. Box 2777, Boise, ID 83701; L.E. Haight Esq. Attorney at Law 805 Idaho Street P.O. Box 2777 Boise ID 83701; Dear Mr. Haight: This is in reply to your letter of September 21, 1973, concerning you desire to disconnect the interlock system on your new car.; The dealer who sold you the car was required to have the interloc working at the time of sale, pursuant to section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(1)). However, section 108(b)(1) of the Act (15 U.S.C. 1397(b)(1)), provides that the requirements of 108(a)(1) do not apply after the first purchase of the vehicle for purposes other than resale. As a purchaser who intends to use the vehicle, you are therefore not subject to the requirements of the Act and may disconnect the interlock.; Despite the absence of legal sanctions for disconnecting the interlock we would hope that you could find a way to adjust the belt so that it could be worn without aggravating your bursitis. The physical sanctions for an unbelted person in a crash can be serious indeed.; Sincerely, Richard B. Dyson |
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ID: aiam3754OpenSherry McBride, The Good Sam Club, P.O. Box 500, Agoura, CA 91301; Sherry McBride The Good Sam Club P.O. Box 500 Agoura CA 91301; Dear Ms. McBride: As requested in your letter of July 8, 1982, please find a copy of th agency's July 1, 1982 letter to Arthur L. Smith of Tempe, Arizona explaining the application of the Federal odometer laws to devices which tow vehicles without the odometer registering the towed mileage. *Motor Vehicle Information and Cost Savings Act* (15 U.S.C. 1981 *et seq.*) and the *Odometer Disclosure Requirements* (49 CFR Part 580).; As we stated in our letter to Mr. Smith, the agency does not hav sufficient information to determine whether any violation of the law has occurred with respect to these particular devices. However, the agency views devices which cause the odometer not to register mileage when the vehicle is towed as prohibited by the Federal odometer laws.; If you have any further questions, please do not hesitate to write. Sincerely, David W. Allen, Assistant Chief Counsel |
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ID: aiam4091OpenMr. Donald H. Giberson, Assistant Director, Division of Motor Vehicles, Department of Law and Public Safety, State of New Jersey, 26 South Montgomery Street, Trenton, NJ 08666; Mr. Donald H. Giberson Assistant Director Division of Motor Vehicles Department of Law and Public Safety State of New Jersey 26 South Montgomery Street Trenton NJ 08666; Dear Mr. Giberson: This responds to your request for an interpretation of FMVSS No. 121 *Air Brake Systems*. You asked whether vehicles equipped with 'Mini-Max' brakes, produced by Transquip Industries, Inc., comply with the standard. You stated that since the heavy spring is omitted and only a single diaphragm is used, there is no way the brake can function if the diaphragm ruptures. Your question is responded to below. We note that Motor Carrier Regulation 393.40 is administered by the Bureau of Motor Carrier Safety (BMCS) rather than by the National Highway Traffic Safety Administration (NHTSA). We have sent a copy of this correspondence to BMCS in order that they may respond to that part of your request.; By way of background information, NHTSA does not provide approvals o motor vehicles or 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 safety standards. The following represents our opinion based on the facts provided in your letter.; Section S5.6.3 provides in relevant part: >>>The parking brake system shall be capable of achieving the minimu performance specified in either S5.6.1 or S5.6.2 with any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (except failure of a component of a brake chamber housing). . . .<<<; The single diaphragm used in the Mini-Max brake is common to both th service and parking brake systems. As part of the service brake system, it is part of a brake system 'other' than the parking brake system. Therefore, since the diaphragm is not a component of a brake chamber housing, section S5.6.3 requires that a vehicle must be able to achieve the minimum performance specified either in S5.6.1 or S5.6.2 in the event of a diaphragm failure.; We do not have sufficient data to determine whether particular vehicle equipped with Mini-Max brakes would meet the requirements of S5.6.1 or S5.6.2 in the event of a diaphragm failure. The answer to that question could depend on the nature of the particular vehicle. It is possible, of course, that a vehicle could be capable of meeting the requirements of S5.6.1 or S5.6.2 as a result of the braking force provided by the other parking brakes whose diaphragms have not failed.; We note that the California Highway Patrol (CHP) has raised this issu and other issues relating to the compliance and overall safety of Mini-Max brakes in connection with a petition for rulemaking, and that International Transquip has submitted comments on CHP's analysis. We have enclosed for your information a notice granting the CHP petition and an interpretation letter to International Transquip. The CHP and Mini-Max submissions have been placed in the Petitions for Rulemaking (PRM) Docket for FMVSS No. 121. If you desire copies of those submissions, please contact: Docket Section, National Highway Traffic Safety Administration, Room 5109, 400 Seventh Street, S.W., Washington, DC 20590 (202-426-2768).; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1769OpenMr. A.O. Haynes,Dennison Manufacturing Company,Framingham, Massachusetts 01701; Mr. A.O. Haynes Dennison Manufacturing Company Framingham Massachusetts 01701; Dear Mr. Haynes:#Please forgive the delay in responding to your lette of October 11, 1974, enclosing sample labels and requesting approval of Dennison's labeling technique to meet the requirements of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*, for labeling brake hose assemblies.#The NHTSA interprets a band a label which encircles the hose completely and attaches to itself. To constitute labeling at all, of course, the band must be affixed to the hose in such a manner that it cannot easily be removed. Furthermore, all of the label information must remain visible after the band has been affixed. From this discussion, you should be able to determine the compliance of your labeling method with the standard. The NHTSA does not approve specific designs in advance because the material, installation method, and underlying material can significantly affect the quality of the specific design.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam2846OpenMr. Glenn Abbott, Cars & Concepts, Inc., 12500 E. Grand River, Brighton, MI 48116; Mr. Glenn Abbott Cars & Concepts Inc. 12500 E. Grand River Brighton MI 48116; Dear Mr. Abbott: This is in response to your letter dated June 27, 1978, asking whethe fog lamps mounted to the surface of a vehicle bumper are removed prior to testing for compliance with Part 581, *Bumper Standard*.; Vehicles subject to the requirements of Part 581 must comply with th protective criteria of section 581.5(c) (49 CFR 581.5(c)) when tested under the conditions stated in section 581.6 (49 CFR 581.6). The test conditions make no provision for removal of fog lamps prior to testing. As was the case under Federal Motor Vehicle Safety Standard 215, *Exterior Protection*, the Part 581 test procedures provide for removal only of trailer hitches before testing. With the added exception of license plate brackets, excluded from the requirements of Part 581 by interpretation (42 FR 24056, May 12, 1977), other equipment (including fog lamps) attached to the bumper system prior to sale of the vehicle to its first purchaser must meet the damage limitations of the standard.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3304OpenMr. Ronald A. Kramer, Assistant General Counsel, Questor Corporation, One John Goerlich Square, Toledo, OH 43691; Mr. Ronald A. Kramer Assistant General Counsel Questor Corporation One John Goerlich Square Toledo OH 43691; Dear Mr. Kramer: This responds to your letter of May 9, 1980,to Stephen Oesch of m office concerning Standard No. 213, *Child Restraint Systems*. You requested an interpretation of whether an alternative configuration you are considering for the Kantwet 'One Step' child restraint would comply with Section 6.1.2.2.1(c) of the standard.; You described the configuration as one in which the crotch strap woul be modified so that it 'is permanently attached to the shield (in a manner similar to the two upper torso restraints which the [agency's] April 29th letter stated were integral parts of the shield. The bottom end of the crotch strap would be buckled to the base of the seat between the child's legs after the child is seated.'; As you have described the modified crotch strap, it is an integral par of the movable shield since it is not a separate device that must be attached to the shield each time the restraint is used, but is formed as a unit with the shield. Since the crotch strap is an integral device, it can be attached during the testing of the restraint.; As mentioned in our letter of April 29, 1980, we urge that you an other manufacturers take the additional step of assuring that the upper torso restraint and the crotch strap permanently remain integral parts of the adjustment or anchorage device to which they are attached.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1339OpenMr. Robert Wood, Hyattsville Auto Glass, 5516 Baltimore Avenue, Hyattsville, MD 20781; Mr. Robert Wood Hyattsville Auto Glass 5516 Baltimore Avenue Hyattsville MD 20781; Dear Mr. Wood: This is in response to your November 29, 1973, request to know i urethane bonding material must be used in the installation of windshields in new motor vehicles not yet sold to a first purchaser for purposes other than resale.; Standard 212, *Windshield mounting*, is a performance standard for ne motor vehicles. We do not require the use of specific bonding materials such as urethane, but only that the vehicle conform to Standard 212, whatever material is used. The New York suit you mentioned may involve a question of due care in the installation of the windshield, separate from the question of meeting a Federal minimum performance standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3611OpenMr. Koji Tokunaga, Manager, Engineering, Isuzu Motors America, Inc., 21415 Civic Center Drive, Southfield, MI 48076; Mr. Koji Tokunaga Manager Engineering Isuzu Motors America Inc. 21415 Civic Center Drive Southfield MI 48076; Dear Mr. Tokunaga:#This responds to your letter concerning Safet Standard No. 102, *Transmission Shift Lever Sequence, Starter Interlock, and Transmissions Braking Effect*. You asked whether a 5-speed automatic transmission which you are considering producing meets the requirement of section S3.1.1 that a neutral position be located between forward drive and reverse drive positions.#By way of background information, I would point out that the agency does not give advance approvals of vehicles or equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to determine whether its vehicles or equipment comply with applicable requirements. A manufacturer then certifies that its vehicles or equipment comply with all applicable standards. Therefore, the following statements only represent the agency's opinion based on the information provided in your letter.#In reference to the diagram enclosed with your letter, the relevant question is whether, in accordance with the above requirement, there is a neutral position between the HD (highway drive) and R (reverse) positions. As explained below, it is our opinion that the answer to that question is yes.#Your letter states that 'the transmission is neutral whenever the shift lever is at any place on the horizontal line (including its left and right extreme ends) at the center of which the mark 'N' is shown.' Further, your letter indicates that 'the shift lever is spring-loaded to return to the center of the horizontal line ('N' position) whenever the lever is left free on that line.'#In shifting between HD and R, the lever must cross the horizontal line. We understand that if the lever is merely held on the horizontal line at the crossing point, i.e., the extreme right, the transmission will be in neutral. Further, we understand that if the lever is left free in that position, it will return to the center of the horizontal line where it will remain in neutral. Based on these two understandings, it is our opinion that the extreme right crossing point constitutes a neutral position between the HD and R positions.#Sincerely, Frank Berndt, 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.