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: 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; |
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ID: aiam2903OpenMr. William Shapiro, Manager, Regulatory Affairs, Product Planning and Development, Volvo of America Corporation, Rockleigh, NJ 07647; Mr. William Shapiro Manager Regulatory Affairs Product Planning and Development Volvo of America Corporation Rockleigh NJ 07647; Dear Mr. Shapiro:#This is in response to your letter of September 20 1978, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 101-80, *Controls and Displays*.#Specifically, you asked whether the km/h label on Volvo speedometers could appear in upper case letters instead of the lower case letters appearing in Table 2 of the standard. The answer is yes.#Section 5.2.3 of the standard provides that 'any such display for which no symbol is provided in Table 2 shall be identified by the word or abbreviation shown in column 3.' There is no requirement that the identifying words or abbreviations be in the same type face, type size, or case as those printed in the Federal Register. Therefore, as long as the abbreviations are the same as those appearing in Table 2 and are visible, no problem arises because Volvo wishes to use upper case, rather than lower case letters.#Sincerely, Joseph J. Levin, Jr., Chief Counsel; |
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ID: aiam4584OpenMr. Robert H. Munson Director, Automotive Safety Office Environmental and Safety Engineering Staff Ford Motor Company The American Road Dearborn, MI 48121; Mr. Robert H. Munson Director Automotive Safety Office Environmental and Safety Engineering Staff Ford Motor Company The American Road Dearborn MI 48121; "Dear Mr. Munson: This responds to your letter in which you suggeste that there are some apparently inconsistent provisions in Standard Nos. 208, Occupant Crash Protection (49 CFR /571.208) and 209, Seat Belt Assemblies (49 CFR /571.209). With respect to manual belt systems installed at front outboard seating positions in a vehicle which is certified as complying with the dynamic testing requirements in Standard No. 208, you asked whether those belt systems may be equipped with load limiters, such that the belt assembly does not comply with the elongation requirements in Standard No. 209. For the reasons explained below, the answer is no. Your letter suggested that Standard No. 209 contains two different provisions that yield inconsistent answers to this question. On the one hand, section S4.5(b) of Standard No. 209 reads as follows: 'A Type 1 or Type 2 seat belt assembly that includes a load limiter and that does not comply with the elongation requirements of this standard may be installed in motor vehicles only in conjunction with an automatic restraint system as part of a total occupant restraint system.' Section S3 of Standard No. 209 defines a 'load limiter' as 'a seat belt assembly component or feature that controls tension on the seat belt to modulate the forces that are imparted to occupants restrained by the belt assembly during a crash.' These provisions of Standard No. 209 seemingly preclude the use of a load limiter on manual belts, if the load limiter results in the belt assembly not complying with those elongation requirements, unless the seating position in which such manual belts is also equipped with an automatic restraint system. Accordingly, dynamically tested manual belts installed at seating positions that do not include any automatic restraint system could not be equipped with a load limiter, if the load limiter resulted in the belt no longer complying with the elongation requirements. On the other hand, section S4.6 of Standard No. 209 exempts dynamically tested manual belts from the elongation requirements of the standard, as well as the webbing width and strength requirements. This exemption applies without respect to whether the dynamically tested manual belt is equipped with a load limiter. Ford suggests that this provision means that a manual belt installed at a front outboard seating position could be equipped with a load limiter, even if the load limiter resulted in the belt assembly not complying with the elongation requirements, provided that the vehicle in which the belt was installed was certified as complying with the dynamic testing requirements in Standard No. 208. In your letter, you said that it was Ford's interpretation that the requirements of S4.6 of Standard No. 209 were meant to limit the prohibition in S4.5 of Standard No. 209, by permitting the use of load limiters that result in the belt assembly no longer complying with the elongation limits on either automatic belts or dynamically-tested manual belts. You suggested that the reasoning that caused the agency to limit the use of load limiters that result in the belt not complying with the elongation requirements to automatic belts only, in section S4.5, does not apply to dynamically tested manual belts. You quoted the following language from the notice that established S4.5: T here are currently no dynamic performance requirements or injury criteria for manual belt systems used alone. There are no requirements to ensure that a load-limiting belt system would protect vehicle occupants from impacting the steering wheel, instrument panel, and windshield, which would be very likely if the belts elongated beyond the limits specified in Standard No. 209. Therefore, the elongation requirements are necessary to ensure that manual belts used as the sole restraint system will adequately restrain vehicle occupants. 46 FR 2618, at 2619, January 12, 1981. You noted that this reasoning is now outmoded for some manual belts, because dynamic testing requirements have been established for certain manual belts. In fact, you asserted that the agency has expressly recognized this by exempting dynamically-tested manual belts from the elongation requirements of Standard No. 209. Accordingly, you believe that S4.5 of Standard No. 209 should be interpreted to permit the use of load limiters that cause the belt to no longer comply with the elongation requirements on either automatic belts or dynamically tested manual belts. As further support for this position, your letter suggested that the agency's notices establishing dynamic testing requirements for manual belt systems show an intent to treat dynamically-tested manual belts in the same way as automatic belts for the purposes of Standard No. 209. You referred to our rule adopting dynamic testing requirements for manual safety belts in front outboard seating positions of passenger cars (51 FR 9800, March 21, 1986), the rule extending dynamic testing requirements to manual belts installed at front outboard seating positions of light trucks and multipurpose passenger vehicles (52 FR 44898, November 23, 1987), and the denial of petitions for reconsideration asking the agency to rescind the exemption of automatic belts and dynamically tested manual belts from the webbing width, strength, and elongation requirements of Standard No. 209 (53 FR 5579, February 25, 1988). Because of the agency's consistent expression in these three notices of its intent to treat dynamically tested manual belts in the same way automatic belts are treated under Standard No. 209, you believe that the reference in S4.5(b) of Standard No. 209 permitting load limiters on belts used 'in conjunction with an automatic restraint system' should be interpreted to mean load limiters may be installed on belts used in conjunction with an automatic or dynamically tested manual restraint system. I do not concur with your suggested interpretation. I believe that sections S4.5 and S4.6 yield inconsistent answers to your question. Section S4.6(a) exempts manual belts from elongation requirements. However, it does not speak to the consequence of installing a load limiter on a belt that does not comply with those requirements. Section S4.5(b) does speak to this issue. It says that such a belt may be used only in conjunction with an automatic restraint. To be more specific, section S4.5 expressly provides that a belt assembly that 'includes a load limiter and that does not comply with the elongation requirements of this standard may be installed in a motor vehicle only in conjunction with an automatic restraint system as part of a total occupant restraint system.' I appreciate that the discussion you quoted from the 1981 notice is consistent with your argument that load limiters should be permitted on any dynamically-tested manual belt. Nevertheless, regardless of whether you believe that NHTSA intended to make or should have made such a change when in adopting dynamic testing requirements for manual belts, it is not possible to interpret the term 'automatic restraint system,' as used in S4.5, to mean 'automatic restraint system or dynamically tested manual restraint system.' An interpretation cannot add or delete requirements that are not contained in the language of the standard itself. When the agency promulgates a safety standard specifying performance requirements for vehicles or items of equipment to accomplish a particular safety purpose, that safety standard sets forth all the requirements with which the vehicles or equipment must comply. If the requirements in the safety standard do not fully address or ensure the implementation of some aspect of the underlying safety purpose, that aspect is not part of the standard. Since an interpretation cannot amend the language of a safety standard, the agency's only recourse in these situations is to undertake rulemaking to amend the language of the standard. You asked that we treat your request for an interpretation as a petition for rulemaking if, as we have done, we concluded that your suggested interpretation was incorrect. We will notify you of our response to this petition as soon as we complete our review of it. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3241OpenMr. Richard C. Stehlik, President, R.C.S. Enterprises, Inc., P.O. Box 925, Waynesboro, VA 22980; Mr. Richard C. Stehlik President R.C.S. Enterprises Inc. P.O. Box 925 Waynesboro VA 22980; Dear Mr. Stehlik: This responds to your letter of February 12, 1979, to Mr. Vladisla Radovich asking whether your 'Kar-Kot' rear seat extension must comply with the Federal motor vehicle safety standard covering child restraints. Your letter was forwarded to my office for reply.; The Federal standard currently in effect for child restraints, Standar No 213, *Child Seating Systems* (49 CFR 571.213), does not apply to 'systems for use only by recumbent or semi-recumbent children.' According to the literature you enclosed with your letter, the Kar-Kot 'has been designed to span the rear floor area and greater part of rear seat' and was 'developed for sleeping/resting'. Since the Kar- Kot is to be used only by recumbent or semi-recumbent children, it is thus exempt from the current standard.; The upgraded version of the child restraint standard, Standard No. 213 *Child Restraint Systems* (44 FR 72131, December 13, 1979), is scheduled to go into effect on June 1, 1980. That standard applies to any device, including devices for use by recumbent or semi-recumbent children, 'designed for use in a motor vehicle to restrain, seat , or position children who weigh not more than 50 pounds.' If the 'Kar-Kot' will only be used by children larger than those intended to be covered by Standard No. 213, *Child Restraint Systems*, your product would not be required to meet the performance requirements of the standard. We note that the literature accompanying your letter makes no mention of any size or age limitations for child (sic) using your product. If the Kar-Kot is not to be used by children under 50 pounds, it should be clearly and permanently labeled to show that it is to be used by a specific size and age range of children.; Regardless of whether it is covered by the standard or not, you product is an item of motor vehicle equipment. Therefore, the recall and remedy provisions of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1411-1420) would apply to any safety- related defects in the Kar-Kot.; If you have any further questions, please let me know. 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.