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: nht76-5.1OpenDATE: 01/23/76 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: AB Stil-Industri TITLE: FMVSS INTERPRETATION TEXT: This responds to Stil-Industri's December 12, 1975, question whether S5.2(d)(1) of Standard No. 209, Seat Belt Assemblies, specifies, in the case of a push-button release, the location and direction of force application used in testing the release under the requirements of S4.3(d)(1). Section S5.2(d)(1) provides in part: (1) . . .The buckle release force shall be measured by applying a force on the buckle in a manner and direction typical of those which would be employed by a seatbelt occupant. For pushbutton-release buckles, the force shall be applied at least 0.125 inch from the edge of the push-button access opening of the buckle in a direction that produces maximum releasing effect. . . The NHTSA interprets these provisions of S5.2(d)(1) to permit the manufacturer to apply force in the direction and location that provides the best possible mechanical advantage relative to the manufacturer's buckle design. The only limitation in the case of a push-button design is that the manufacturer must not apply the force any closer than 0.125 inch from the edge of the push-button access opening. Yours truly, ATTACH. CHIEF COUNSEL -- NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION DECEMBER 12, 1975 GENTLEMEN, WE ARE A SWEDISH COMPANY PRODUCING SAFETY-BELTS FOR DIFFERENT CARS AND ALL DIFFERENT MARKETS. WE WOULD KINDLY ASK YOU TO HELP US WITH SOME QUESTIONS WE HAVE ABOUT HOW TO INTERPRET SECTION (1) IN S.5.2 (D) ABOUT BUCKLE RELEASE. FROM THE PASSAGE: "THE BUCKLE RELEASE FORCE SHALL BE. . . . .TO:. .. RELEASING EFFECT". WE WOULD LIKE TO ASK YOU THE FOLLOWING QUESTIONS. WHERE ON THE PUSH BUTTON SHALL WE APPLY THE FORCE? IN A POSITION WHICH IS TYPICAL FOR THE SEAT BELT OCCUPANT? IN THE CENTER? 1/8 INCH FROM WHICH EDGE? IN WHAT DIRECTION? THESE QUESTIONS ARE OF GREAT IMPORTANCE FOR US AND WE AWAIT YOUR REPLY WITH GREAT INTEREST. WE ARE VERY GREATFUL IF YOU COULD ANSWER AS SOON AS POSSIBLE. SINCERELY YOURS AB STIL-INDUSTRI; HANS SYLVEN -- CHIEF OF CONSTRUCTION |
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ID: nht76-5.14OpenDATE: 05/03/76 FROM: AUTHOR UNAVAILABLE; William T. Coleman Jr.; NHTSA TO: Delbert L. Latta; House of Representatives TITLE: FMVSR INTERPRETATION TEXT: Thank you for your March 23, 1976, request for consideration of the views of a constituent that provision of air cushion restraint systems in passenger cars would be too costly, and that motor vehicle regulation should concentrate on used vehicles because they are equipped with fewer safety and emission features. As you are aware, the National Traffic and Motor Vehicle Safety Act (the Act) (15 U.S.C. @ 1391 et seq.) directs the Secretary of Transportation to issue motor vehicle standards that will reduce the number of accidents and deaths, and the severity of injuries, that occur on our nation's highways. The National Highway Traffic Safety Administration (NHTSA) of the Department of Transportation evaluates the available means to meet this goal. Restraining vehicle occupants to protect them against impact with the vehicle interior in a crash offers one of the greatest opportunities for improving motor vehicle safety. Reliance on existing seatbelt systems has prevented only a small portion of the death and injuries that occur from impact with the vehicle interior. For this reason, other means of providing restraint are under consideration. I can assure you that the issues of purchase cost, replacement cost, and the alternatives to air cushions are being included in this consideration. The safe operation of motor vehicles has traditionally been regulated by the individual States and not the Federal Government. While the Act does not authorize the retrofit of safety devices to vehicles in use, the NHTSA has issued a highway safety program standard for State periodic motor vehicle inspection programs (23 CFR @ 1204.4). Part 570, Vehicle in Use Standards (49 CFR Part 570), sets forth a procedure for inspection of older vehicles for use by the States in implementing the program standard. Also, the NHTSA has established demonstration diagnostic inspection projects that include emission as well as safety inspection of vehicles in use. I have no basis for comment on the reported decision by Allstate Insurance Company not to consider the effects of bumper modification in establishing its premium structure. I trust that this response will answer your constituent's questions. |
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ID: nht74-3.39OpenDATE: 05/06/74 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Rozner and Yorty TITLE: FMVSS INTERPRETATION TEXT: This responds to your March 26, 1974, request for information on seat belt regulations as they concern reclining passenger seats. Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection, requires passenger cars to be equipped with seat belt assemblies, but it does not contain performance requirements to regulate the effectiveness of the belt assembly with the seating system in the reclining position. Federal Motor Vehicle Safety Standard No. 207, Seating Systems, specifies minimum safety requirements for motor vehicle seats. The requirements of the standard are based on conventional seat designs that normally incorporate a seat back angle of approximately 25 degrees rearward inclination from the vertical. Standard No. 207 requires that reclining seats be tested in their most upright position and does not require seats to be tested in the reclining position. The National Traffic and Motor Vehicle Safety Act of 1966 preempts state motor vehicle safety regulations which are not identical to the Federal standards with regard to the same aspect of performance and therefore any state law would be identical to Standards Nos. 207 and 208 on these aspects of performance (15 U.S.C. @ 1392 (d)). The engineering staff is not aware of any studies in the area of seat belts and reclining seats. Yours truly, ROZNER AND YORTY March 26, 1974 National Highway Traffic Safety Admin. Re: Three point restraint on reclining passenger seat Gentlemen: I represent a passenger who was injured while she was sleeping in a bed-like reclining passenger seat. She slid out the back. She had a conventional seat belt on, but it did not help. Are there any regulations either in the past or the future that would apply to this situation, either State or Federal? Have there been any studies on this subject or any interest in this subject. I shall appreciate whatever help you can give me. Very truly yours, William A. Goichman |
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ID: nht74-4.41OpenDATE: 01/11/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Corner Sterling & Machell Avenues TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of November 21, 1973 to "U.S. Bureau of Safety" expressing your view that "the automobile industry should . . . have some type of clutch to reverse action when the closing motion of the (power) window meets any resistance." I enclose a copy of Federal Motor Vehicle Safety Standard No. 118 Power-Operated Window Systems which has applied to all passenger cars and multipurpose passenger vehicles with power windows manufactured since February 1, 1971. The objective of the standard is to minimize the likelihood of injury or death occurring when a person is caught between a closing window and its frame, channel, or seat. The NHTSA determined that the most cost-effective way to accomplish this objective was by prohibiting operation of power windows when the ignition key is either in the ignition "off" position or removed. As you will see from the enclosure, consideration was given to mechanisms that would reverse the direction of the window. We appreciate your interest in motor vehicle safety. ENC. December 11, 1973 Dr. Irvin Jacobs, M.D. The circumstance and comment in your letter of November 21, 1973, regarding automatic window closing operation is noted. The matter is deemed to be in the jurisdiction of the U. S. Department of Transportation (DOT). Therefore, we are forwarding your letter with a copy of this acknowledgement to DOT for their attention and an appropriate reply. JOHN J. KLOCKO Chief, Materials Handling Technology Center cc: FMSMUSS-118 U.S. Dept. of Transportation November 21, 1973 U. S. Bureau of Safety Washington D. C. Gentlemen: Recently one of our young patients was brought in after having his head caught in the window of a car door after the automatic window closing operation had been started. Fortunately, this was not a serious accident; however, it could have been. It seems the automobile industry should be prevailed upon to have some type of clutch to reverse action when the closing motion of the window meets any resistance. Sincerely, IRVIN JACOBS, M.D. |
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ID: nht73-1.43OpenDATE: 09/26/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Sekurit-Glas Union GmbH TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of July 19, 1973, requesting information regarding the marking requirements in FMVSS No. 205 for automobile safety glass. With respect to your request for a copy of the marking requirements, they may be found in paragraph S6. of the enclosed copy of the standard, and in section 6 of American National Standard Z26.1 - 1966. The latter standard can be obtained by writing to the American National Standards Institute, 1430 Broadway, New York, New York 10018. Information on various State requirements should be obtained from Mr. Armond Cardarelli, American Association of Motor Vehicle Administrators, Suite 500, 1828 L Street, N.W., Washington, D.C. 20036. You ask whether marking requirements can be met using a specific format you include in your letter, and refer to "Approval" and "Supplemental" markings. It is not clear to us to what you refer, as we prescribe neither "approval" nor "supplemental" markings in the standard, and perhaps we will be better able to answer any questions you may have after you have had an opportunity to review the requirements. Yours truly, Enclosure July 19, 1973 Administrator -- National Highway Traffic Safety Administration Ref.: Markings of Safety Glass Dear Sirs, According to the FMVSS 205 all the safety glasses built in cars have to be marked. Beside the prescriptions of the Department of Transportation there are other special prescriptions for each state (for instance California). Please could you send us an exact list of all these special specifications. Could you send us as well the concerned regulation or a list from which we can take the form and the contains of the markings. Is it sufficient to write as Approval Markings DOT . . . /M . . . /AS and all other denominations, as for instance laminated, Kinonglas-Kristall-HI-BFG, plate in the Supplemental Markings? We would be very grateful if you could answer our letter as soon as possible. Yours sincerely, SEKURIT-Glas Union GmbH i.V. i.A. |
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ID: nht95-2.52OpenTYPE: INTERPRETATION-NHTSA DATE: April 25, 1995 FROM: A. P. Corrado -- Director, Market Development Gen Corp Aerojet, Electronic Systems Division TO: John Womack -- Acting Chief Council, NHTSA TITLE: NONE ATTACHMT: ATTACHED TO 6/14/95 LETTER FROM JOHN WOMACK TO A. P. CORRADO (A43; STD. 208) TEXT: Dear Mr. Womack, The purpose of this letter is to request clarification from NHTSA concerning the application of FMVSS 208, 49 CFR @ 571.208 (Occupant Crash Protection), with respect to an "Out-Of-Position) front outboard passenger. As you know, S4.1.5.3 of FMVSS 208 requires that all passenger cars manufactured on or after September 1, 1997, comply with the automatic front/angular protection system of S4.1.5.1(a)(1) "by means of an inflatable restraint system at the driver's and right front passenger's position". The term "inflatable restraint system" is defined in S4.1.5.1(b) as "an air bag that is activated in a crash". Some in the industry have interpreted this standard -- particularly the word "activated" -- as mandating a system that automatically deploys a passenger-side air bag under all circumstances. However, we do not believe the term "activate" in the defin ition of "inflatable restraint system" is intended to mean "deploy in all cases". Specifically, given the purpose and intent of the Standard, we do not believe that the Administration intended to require deployment of an airbag where the deployment itse lf is likely to cause serious injury or death. This distinction is critical given the development of sophisticated sensing devices that offer the potential of discriminating between an In-Position passenger and an Out-Of-Position passenger. Such systems, being developed initially to detect the pr esence of rear facing infant seats, offer the prospect of reducing the likelihood of serious injury or death to Out-Of-Position passengers by purposely inhibiting or restricting full deployment of the passenger side air bag. Because we are confident that NHTSA does not intend to preclude the development or application of such sophisticated sensor systems, we would appreciate your confirmation that FMVSS 208 does not preclude the use of inflatable restraint systems that by design inhibit deployment of a passenger air bag in those identified cases where the likelihood and severity of passenger injury would be greater with air bag deployment than without. |
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ID: nht95-2.55OpenTYPE: INTERPRETATION-NHTSA DATE: April 26, 1995 FROM: John Womack -- Acting Chief Counsel; NHTSA TO: Richard Kreutsiger -- Executive Director NYSBDA TITLE: NONE ATTACHMT: ATTACHED TO 2/11/95 LETTER FROM RICHARD KREUTZIGER TO WALTER MYERS TEXT: Dear Mr. Kreutsiger: This responds to your facsimile request for an interpretation of the question "is there any Federal mandate . . . that provides a specific date or time frame in which a manufacturer has to change model year dating . . . if there is no change in the vehic le production or design makeup." I apologize for the delay in responding. The short answer to your question is that our regulations require model years to change within a two year time frame but do not prescribe the date that may be selected for the mod el year changeover. Regarding this agency's regulations, your letter indicated that you had found the provision in 49 CFR part 565, Vehicle Identification Number - Content Requirements, specifying that the model year must be included as part of the vehicle identification nu mber (VIN). You may not have noticed that section 565.3(h) of that part defines "model year" as "the year used to designate a discrete vehicle model irrespective of the calendar year in which the vehicle was actually produced, so long as the actual peri od is less than two calendar years." Therefore, even if a vehicle is identical to the vehicles produced in any number of preceding years, the model year must change at a frequency of less than two years. My understanding is that your letter is only concerned with model years for school buses, which are not subject to the corporate average fuel economy program under Chapter 329 of title 49 of the U.S. Code. For passenger cars and light trucks, model year is defined in section 32901(15) for fuel economy purposes as "the annual production period of a manufacturer, as decided by the [EPA] Administrator, that includes January 1 of that calendar year; or that calendar year if the manufacturer does not have a n annual production period." I hope this information is helpful. If you have any questions, please contact Paul Atelsek of my staff at this address or at (202) 366-2992. |
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ID: nht73-4.43OpenDATE: 08/08/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: DPD Mfg. Co., Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of July 31, 1973, in which you asked our opinion as to the effect of Standard 208 upon your vehicle air conditioner installations. Standard 208, Occupant Crash Protection, for the next few years allows manufacturers the option of providing either seat belts or passive protection systems, of which the air cushion is presently the most widely considered, in various combinations. The decision as to when passive protection would become mandatory has not yet been made. The passive protection requirements of Standard 208 are measured with instrumented dummies, and the standard does not specifically regulate the method by which manufacturers provide the protection in the various crash tests. The way a manufacturer chooses to meet the standard, including the arrangement of the components of the vehicle interior, is thus left to his own discretion and the NHTSA does not offer opinions as to particular vehicle designs. The "vacuum advance system" you refer to evidently refers to the air pollution control programs of the Environmental Protection Agency. That agency's address is Washington, D.C. 20460. Yours Truly, dpd mfg. co., inc. July 31, 1973 The Office of the Chief Counsel National Highway Traffic Safety Administration We manufacture air conditioners for small cars imported into the United States Accordingly, we are interested in providing units which will not interfer with vehicle safety devices. Our 1973 air conditioners are usually installed under the dash or in center console. See attached photos of our air conditioners installed and the vehicle without air conditioning. We have heard that a vacuum advance system may be under consideration and the air-bag protection system would definitely bear on our future design of air conditioners. Also, we need your opinion as to the effect of Law 208 upon our air conditioners. The above information is most urgently requested since we are proceeding rapidly with the 1974 air conditioners. Thanking you in advance for an early reply. O. D. Hunter Director of Training and Publications Enclosures |
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ID: nht92-3.7OpenDATE: 10/26/92 FROM: KENNETH W. WEBSTER II -- PROJECT ENGINEER, TRANSPORTATION RESEARCH CENTER, INC. TO: PAUL JACKSON RICE -- OFFICE OF CHIEF COUNCIL, NHTSA ATTACHMT: ATTACHED TO LETTER DATED 12-24-92 FROM PAUL J. RICE TO KENNETH W. WEBSTER II (A40; STD. 124) TEXT: Thank you for your response concerning the FMVSS 114. We appreciate the time an efforts of the Chief Council to reach a decision concerning the letters we have mailed recently. This correspondence should be the our last request for the present time. This correspondence is a request for clarification of CFR Title 49, Part 571.124, Paragraph S5 (FMVSS 124, "Accelerator Control Systems"). The Transportation Research Center Inc. (TRC) has performed the FMVSS 124 tests on passenger cars at the lowest extreme temperature of -40 degrees F. In some cases it becomes very difficult or impossible to start a test vehicle after a 12 hour soak at -40 degrees F. Paragraph S5 specifies that the engine must be running under any load condition during the test performance. If all cold starting improvements have been incorporated but the engine will not start at the -40 degrees F test condition, which of the following would be correct: (1) Test with engine not running at the -40 degrees F test condition. (2) Raise temperature until engine will start. Record test temperature and perform test. If number one is correct, does the vehicle fail if the time is greater than the requirement even though the vehicle meets the requirement at a slightly higher temperature with the engine running? If number two is correct, what would be the allowable low temperature range in which the vehicle must be started and tested to check compliance? If neither is correct, please indicate proper measures that must be taken in this situation. A manufacturer has indicated that the "due care" clause is not an acceptable explanation of actions to take in this case. Please provide TRC a response in writing, regarding the Chief Council's position. If you have any questions or require further information before you can determine a position, please contact the undersigned at (513) 666-2011. We thank you in advance for your expeditious reply. |
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ID: nht88-2.36OpenTYPE: INTERPRETATION-NHTSA DATE: 05/31/88 EST FROM: ERIKA Z. JONES -- NHTSA CHIEF COUNSEL TO: GARRY GALLAGHER -- VICE PRESIDENT, METZELER MOTORCYCLE TIRE TITLE: NONE ATTACHMT: FEBRUARY 11, 1988 LETTER FROM GALLAGHER TO COOK IS ATTACHED TEXT: I am writing in response to your letter of February 11, 1988 that requested "written confirmation and approval" to add the word "reinforced" to the sidewall of the Metzeler Motorcycle ME88 Marathon model motorcycle tire. As discussed below, it is our op inion that Federal Motor Vehicle Safety Standard 119 does not prohibit the addition of the word "reinforced." It is important to note that the National Highway Traffic Safety Administration does not approve motor vehicles or motor vehicle equipment, nor do we endorse commercial products. Instead, the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S .C. 1381 et seq.) establishes a "self certification" process under which each manufacturer is required to certify that its products meet all applicable safety standards. The Act prohibits the manufacture or sale of a noncomplying product. Standard No. 119; New pneumatic tires for vehicles other than passenger cars establishes performance and marking requirements for tires for use on multipurpose passenger vehicles, trucks, buses, trailers, and motorcycles. Paragraph S6.5 of Standard No. 1 19 requires that certain information be labeled on the sidewalls of each tire subject to this standard. The agency has frequently stated in past interpretations that the purpose of these labeling requirements is to provide the consumer, in a clear and s traightforward manner, with technical information necessary for the safe use of the tires. Standard No. 119 permits tire manufacturers to label additional information on the sidewall on the tires, provided that the additional information does not obscur e or confuse the meaning of the required information, or otherwise defeat its purpose. Assuming that the addition of the word "reinforced" is not made in such a way that it obscures or confuses the meaning of the required information, Standard No. 119 d oes not prohibit the addition of the word "reinforced" to the motorcycle tire sidewall. I hope the information provided above will be useful to you and to Metzeler Motorcycle Tire. If there are any further questions or if you need more information, please do not hesitate to write to me. |
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.