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: aiam2634OpenMr. Paul F. Bennett, Chief Engineer, Utility Trailer Manufacturing Co., P.O. Box 1299, City of Industry, California 91744; Mr. Paul F. Bennett Chief Engineer Utility Trailer Manufacturing Co. P.O. Box 1299 City of Industry California 91744; Dear Mr. Bennett: This responds to your May 20, 1977, letter asking whether your propose certification labels comply with the requirements of Part 567, *Certification*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approval of compliance with Federal safety standards or regulations. We will, however, issue an opinion of whether your labels appear to comply with the regulations. The labels you submitted appear to comply with all but one of the requirements of Part 567 and Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. On your certification labels, you list the symbol 'W/' before the rim information. This symbol should be dropped from the label. Further the rim size designation should use the symbol 'x' between the diameter and width. Information supplied on a certification label must be provided in the form detailed in Part 567.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3926OpenMr. John L. Strickland, J.S. Welding, Rt. 5 Box 496, Denham Springs, LA 70726; Mr. John L. Strickland J.S. Welding Rt. 5 Box 496 Denham Springs LA 70726; Dear Mr. Strickland: I am responding to your February 20, 1985 request for informatio regarding Federal regulation of trailer manufacturing.; There is no Federal licensing requirement for the manufacture o trailers, which are considered motor vehicles under Federal law. As a manufacturer of a motor vehicle, however, you must submit identification information to the National Highway Traffic Safety Administration under 49 CFR Part 566, *Manufacturer Identification*. You must also certify that each trailer complies with all applicable Federal regulations. The procedure is specified in 49 CFR Part 567.; At this time, the only safety standards applicable to all trailers ar Safety Standard No. 108, *Lamps, reflective devices, and associated equipment*, Safety Standard No. 120, *Tire Selection and rims for motor vehicles other than passenger cars*, and Safety Standard No. 115, *Vehicle Identification Number-Basic Requirements*. The content requirements for the vehicle identification number are found at Part 565. Trailers with certain braking systems also must meet Safety Standard No. 106, *Brake hoses*, Safety Standard No. 116, *Motor vehicle brake fluids*, and Safety Standard No. 121, *Air brake systems*. These standards are found in Part 571 of 49 CFR.; I am enclosing an information sheet that explains how you can obtai copies of these regulations. If you have any further questions, please feel free to contact me.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2321OpenMr. Donald L. Thompson, Managing Editor, NTDRA Dealer News, 1343 L Street, N.W., Washington, D.C. 20005; Mr. Donald L. Thompson Managing Editor NTDRA Dealer News 1343 L Street N.W. Washington D.C. 20005; Dear Mr. Thompson: I am writing to point out an error in an article that appeared in th May 24-31, 1976, issue of *NTDRA Dealer News* (Vol. XXXIX, No. 15). The article summarized a recent Federal Register notice (41 FR 18659, May 6, 1976, Docket No. 71-19, Notice 4) that delayed certain effective dates of Federal Motor Vehicle Safety Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars.*; The error appears in the paragraph of the article that reads: >>>Section 5.1.1 says that rims used must be those designated by th tire manufacturer. The effective date has been changed from March 1, 1977 to September 1, 1979.<<<; One requirement of S5.1.1 is that a vehicle be equipped with rims tha have been designated by the manufacturer of the vehicle's tires as suitable for use with those tires. The effective date of this requirements was originally established as September 1, 1976, and was not delayed be Notice4. Another requirement of S5.1.1 is that a vehicle be equipped with rims that comply with the standard, i.e., with rims that are marked according to S5.2, *Rim Marking.* Only the effective date of this vehicle requirement was changed from March 1, 1977, to September 1, 1979.; A clarification of these effective dates in a forthcoming issue o *NTDRA Dealer News* would be much appreciated.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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ID: aiam2771OpenMr. W.G. Milby, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W.G. Milby Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to your January 11, 1978, letter asking whether severa joints in your school bus must comply with Standard No. 221, *School Bus Body Joint Strength*.; The terms which establish the applicability of the requirements of th standard to a particular section of a school bus body are defined in S4 of the standard. Read together they establish the following test. If the edge of a surface component (made of homogeneous material) that encloses occupant space in a bus comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose, or is a door, window, or maintenance access panel. Applying this test to the several joints to which you refer, it appears that they do not need to comply with the requirements since they connect panels which are considered to be maintenance access panels.; The National Highway Traffic Safety Administration (NHTSA) notes tha maintenance access panels are granted this exception from the requirements because of their need for removal for routine service to underlying components. The NHTSA will not consider all bus walls as maintenance access panels simply because wiring may be present behind them since routine maintenance would not be required on such wiring. Further, should any of the panels to which you refer in your letter not have wiring or other serviceable components requiring routine maintenance behind them, they will not be treated as maintenance access panels.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3863OpenMr. John B. Walsh, Head, Regulations & Emissions Laboratory, Government Relations Department, U.S Suzuki Motor Corp., 3251 East Imperial Highway, Brea, CA 92621; Mr. John B. Walsh Head Regulations & Emissions Laboratory Government Relations Department U.S Suzuki Motor Corp. 3251 East Imperial Highway Brea CA 92621; Dear Mr. Walsh: This is in reply to your letter of October 31, 1984, to Mr. Vinson o this office, asking for confirmation of a 1972 agency interpretation of Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*.; In pertinent part, Table III of Standard No. 108 requires that, at minimum, a motorcycle be equipped with one taillamp, one stop lamp, and four turn signal lamps. Table IV directs that the stop lamp and taillamp be placed on the vertical centerline, and that the turn signal lamps be placed on each side of the vertical centerline with a minimum edge to edge separation distance of 4 inches between the turn signal lamp 'and tail or stop lamp.' Table IV expressly permits dual stop and taillamps 'symmetrically disposed about the vertical centerline.' No express exception is made to the 4-inch spacing requirement if dual stop or taillamps are installed, raising the question whether the minimum distance must be maintained no matter what the rear lighting configuration may be.; You have called our attention an (sic) interpretation of July 1, 1972 that Motor Vehicle Programs of this agency provided Stanley Electric Company Ltd. In that instance the proposed rear lighting configuration consisted of two combination stop, turn signal, and taillamps placed on either side of the vertical centerline. The agency opined that the minimum separation distance was not applicable to combination lamps when there was 'no tail or stop lamp mounted on the vertical centerline.' You have asked for confirmation that this remains the agency's view.; As you have pointed out Suzuki's proposed design of a unit combinin amber turn signal lamps with red stop and taillamps is similar to current passenger car practice where the minimum distance requirement does not exist. Therefore, this will confirm that the minimum edge to edge separation distance of 4 inches between turn signals and stop and taillamps applies when single stop and taillamps are installed on the vertical centerline, but not when dual stop and taillamps are installed on either side of the centerline.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3530OpenMr. Malcolm J. McCalmon, International Sales Manager, CENTRA Leichtmetall-Rader GmbH, Daimlerstrasse 6, D-6733 Hassloch/Pfalz, West Germany; Mr. Malcolm J. McCalmon International Sales Manager CENTRA Leichtmetall-Rader GmbH Daimlerstrasse 6 D-6733 Hassloch/Pfalz West Germany; Dear Mr. McCalmon: This responds to your letter to Mr. Kratzke of my staff concerning th Federal requirements for vehicle wheels that are to be imported into the United States. You noted in your letter that the wheels would be for 'original equipment on passenger vehicles and non-passenger vehicles (recreation vehicles).' There are two Federal Motor Vehicle Safety Standards which apply to wheel rims. There are no standards applicable to the rest of the wheel assembly, however.; The two applicable standards are No. 110, *Tire selection and rims passenger cars*, and Standard No. 120, *Tire selection and rims for motor vehicles other than passenger cars*. I have enclosed copies of both standards, along with Standards Nos. 109 and No. 119, which are applicable to tires. For those passenger car rims you manufacture there are two requirements, specified in section S4.4 of Standard No. 110. FIrst, the rim must be constructed to the dimensions of one of the rims that is listed under the definition of a test rim in Standard No. 109. This means that the rim must comply with the dimensional specifications shown for that rim size in the current publications of specified standardization organizations, such as the Tire & Rim Association, the European Tyre and Rim Technical Organization, or the Deutsches Institut fur Normnug. Second, in the event of a rapid loss of inflation pressure with the vehicle travelling in a straight line at 60 miles per hour, the rim must retain the deflated tire until the vehicle can be stopped with a controlled braking application.; For those rims you manufacture for use on vehicles other than passenge cars, Standard No. 120 also specifies two requirements. The first requirement, set forth in section S5.1.1, is that the rims on a vehicle must correspond with the size tire on the vehicle i.e., be listed as suitable by the tire manufacturer, pursuant to either Standard No. 109 or No. 119. This would be done in the publications of the standardization organizations, as explainted (sic) above. This requirement is the responsibility of the vehicle manufacturer, since only it knows what size tires will actually be on the vehicle. The second requirement, set forth in section S5.2, is that the rim must be marked with certain specified information.; When a rim manufacturer determines that its rims comply with th requirements outlined above, it may certify the rims and sell them in the United States. In your letter, you inaccurately stated that there is no (sic) a specific DOT certification for rims. While there is no specific DOT certification number, as required by some other standards for items for equipment other than rims, a manufacturer must always certify that each item of motor vehicle equipment complies with all applicable Federal motor vehicle safety standards, pursuant to section 114 of the National Traffic and Motor Vehicle Safety Act of 1966, as amended (15 U.S.C. 1403) (copy enclosed). That section specifies that the certification for items of motor vehicle safety equipment, including rims, may be in the form of a label or tag on the item, or on the outside of a container in which the item is delivered. All of your rims to be sold in this country must contain such a certification.; The United States does not use a certification process similar to th EEC, in which the manufacturer delivers the item to be certified to the governmental entity, and that entity tests the item to determine if it can be certified. Instead, in the United States, the individual manufactuer (sic) must certify that the product complies with all applicable standards. Further, this agency does not require that a certification be based on actual tests of the equipment, we only require that the certification be made with the exercise of due care on the part of the manufacturer. It is up to the individual manufacturer to determine in the first instance exactly what data or information it needs to allow it to certify that the equipment meets all applicable Federal standards. Obviously, with respect to the requirements for rims, a manufacturer is not expected to test if the rims have the necessary markings or if the rim size is listed in one of the publications of a standardization organization.; Should you have any further questions about these standards, feel fre to contact me. If you need further information about the actual process of importing the rims into the United States or the form for the certification, you can contact the U.S. Customs Service Duty Assessment Division at 1301 Constitution Avenue, N.W., Washington, DC 20229.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3160OpenMr. Edward F. Tannery, Theodore Bargman Company, 129 Industrial Avenue, Coldwater, MI 49036; Mr. Edward F. Tannery Theodore Bargman Company 129 Industrial Avenue Coldwater MI 49036; Dear Mr. Tannery: This responds to your recent letter asking whether doors on aftermarke top covers for American Motors Jeeps would have to comply with Safety Standard No. 206, *Door Locks and Door Retention Components*.; Safety Standard No. 206 applies to passenger cars, trucks an multipurpose passenger vehicles, which would include Jeeps. The standard applies only to completed vehicles, however, and not to aftermarket motor vehicle equipment. Therefore, the doors on aftermarket Jeep top covers would not have to have locks. Further, doors on new Jeep vehicles would also not have to comply with the standard if they are 'designed to be easily attached to or removed from' the vehicle, as provided in section S4 of the standard.; Please contact Hugh Oates of my office if you have any furthe questions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4328OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Department, Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Department Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of March 4, 1987, with reference t aiming adjustment of fog lamps. We understand that Stanley is developing a fog lamp and replaceable bulb headlamp with a common lens and housing. Since the portion of the housing also functions as a reflector, the fog lamp moves simultaneously with the headlamp in aiming adjustment. In your view, it will not impair the effectiveness of the headlamp, and you ask for confirmation that the lamp 'is acceptable in the U.S.A.; Federal Motor Vehicle Safety Standard No. 108 contains no requirement for a fog lamp, and would prohibit it only if it impaired the effectiveness of any other lamp mounted on the front of a vehicle that is required by the standard. Assuming that the fog lamp does not impair the effectiveness of the headlamp, its installation would not crate a noncompliance with Standard No. 108. However, in the absence of a Federal standard on fog lamps, the individual States may establish their own requirement for fog lamps. We are unable to advise you whether this design would be acceptable in each of the 50 States, and other jurisdictions in which the Federal standards must be met, we can only advise you that it does not appear prohibited by Federal law.; The American Association of Motor Vehicle Administrators (AAMVA). 120 Connecticut Avenue, N.W., Washington, D.C., 20036 may be able to advise you as to state laws relevant to your design.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3117OpenMr. J. B. H. Knight, Chief, Car Safety and Regulations Engineer, Rolls-Royce Motors Limited Car Division, Crewe Cheshire CW1 3PL, ENGLAND; Mr. J. B. H. Knight Chief Car Safety and Regulations Engineer Rolls-Royce Motors Limited Car Division Crewe Cheshire CW1 3PL ENGLAND; Dear Mr. Knight: This is in response to your letter of August 17, 1979, regarding th requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 208, Occupant Crash Protection, pertaining to the emergency release warning system for automatic belts.; Paragraph S4.5.3.3(b)(1) of the standard requires an audible an visible warning if the driver's automatic belt system is not in use, as determined by the belt latch mechanism not being fastened. On one of your automatic belt designs the latch mechanism consists of a pivoting bar which slips through a small stitched loop on the end of the belt webbing. You note that this latch mechanism can be fastened without the webbing being connected to the pivot bar, and that in such a case the warning system would not operate even though the belt is not in use. Therefore, you ask if you can install a switch in the automatic belt retractor to detect when insufficient webbing is extended from the retractor to engage with the latch on the door frame. You ask if such a system could be used as an alternative to the existing requirement or, if the standard could be amended to allow the alternative.; In answer to your question, a switch in the retractor of an automati belt system would not satisfy the current warning system requirement if the system did not also include a switch in the emergency release latch mechanism. Further, the Agency does not believe that it is necessary to amend the standard to allow such an alternative. Although it may be true that the existing warning system could be defeated in a belt system such as you describe, the same is true with most warning system requirements. For example, if the standard provided the alternative you suggest, the automatic belt could be 'tied-off' after sufficient webbing was withdrawn from the retractor and the warning system would be defeated. As you know, this method has been used to defeat the warning systems of many manual belts in the past. Therefore, we believe the existing requirement is sufficient to warn vehicle occupants that their automatic belt has been released and should be reconnected.; The 'pivot-bar' release mechanism described in you letter appears t comply with the requirements of the standard. However, we believe that the bar should remain in the released position after the belt webbing has been removed so that the warning system will activate. In other words, we assume that the pivot bar does not re-latch automatically after being released but, rather, requires manual re-latching by the occupant.; Regarding your third question we have enclosed, for your information Notice 14, Docket No. 1- 18, which establishes the new requirements related to controls and displays.; Sincerely, Ralph J. Hitchcock, Chief, Crashworthiness Division, Offic of Vehicle Safety Standards; |
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ID: aiam4778OpenMs. Carol Zeitlow Manager, Engineering Services Oshkosh Truck Corporation P.O. Box 2566 Oshkosh, WI 54903-2566; Ms. Carol Zeitlow Manager Engineering Services Oshkosh Truck Corporation P.O. Box 2566 Oshkosh WI 54903-2566; Dear Ms. Zeitlow: This is in reply to your letter of August 1, 1990, t Taylor Vinson of this Office, with respect to Motor Vehicle Safety Standard No. 108. You ask for confirmation that 'the hazard warning light should always over-ride the stop lamp' when they are 'together on a vehicle.' I am pleased to provide that confirmation. Under the relevant SAE materials on stop lamps that are incorporated by rference in Standard No. 108, when a stop signal is optically combined with the turn signal, the circuit shall be such that the stop signal cannot be turned on if the turn signal is flashing. Because the hazard warning system operates through the turn signal lamps, the stop signal cannot be turned on in an optically combined lamp if the hazard system is in use. You have also noted that in your version of Standard No. 108, no reference is made to SAE Standard J1395. It was not until May 15 of this year that Standard No. 108 was amended to incorporate SAE J1395 (with an effective date of December 1, 1990). I enclose a copy of that amendment for your information. If you have any further questions, we shall be pleased to answer them. Sincerely, Paul Jackson Rice 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.