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: aiam3651OpenMr. J. W. Lawrence, Manager, Compliance and Recall, Volvo White Truck Corporation, P.O. Box D-1, Greensboro, NC 27402-1200; Mr. J. W. Lawrence Manager Compliance and Recall Volvo White Truck Corporation P.O. Box D-1 Greensboro NC 27402-1200; Dear Mr. Lawrence: This responds to your letter concerning Safety Standard No. 101 *Controls and Displays*. You asked whether the standard's identification and illumination requirements are applicable to an optional windshield wiper control you are planning to make available on some heavy duty trucks.; By way of background information, the agency does not provide approval of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is up to the manufacturer to assure that its vehicles and equipment comply with applicable Federal motor vehicle safety standards. The following interpretation represents our opinion based on the facts provided in your letter. It also takes into account information provided in a follow-up telephone conversation with Edward Glancy of this office.; The standard wiper controls for the vehicles in question consist of tw knobs which independently control the left and right wipers. These controls provide both the on-off function and variable speed. According to your letter, these controls are identified and illuminated as required by the standard.; The proposed optional control, the specific subject of your letter would provide a time delay for windshield wiper operation during light mist conditions. The control would be a knob which, if turned to the left, would provide no pause, and if turned toward the right, would offer a variable time delay.; We are unable to agree with your suggestion that the control is no covered by Standard No. 101. As discussed below, Standard No. 101 requires that this control, like the standard controls, be identified and illuminated in accordance with the standard's requirements. Additional words or symbols may be provided for the purpose of clarity.; Section S5 of Standard No. 101 requires, among other things, that eac truck manufactured with any control listed in S5.1 or in column 1 of Table 1 meet the requirements of the standard for the location, identification, and illumination of such control. One of the controls listed by S5.1 is 'windshield wiper.' Also, 'windshield wiping system' is among the controls listed in column 1 of Table 1. The issue raised by your letter is therefore whether an optional control for intermittent wiper operation is within the meaning of 'windshield wiper' control and/or 'windshield wiping system' control. It is our interpretation that such a control is within the meaning of both terms.; Neither the term 'windshield wiper' control nor 'windshield wipin system' control is limited to specific wiper functions, such as on-off, variable speed, etc. Since a control for intermittent wiper operation controls one function of windshield wipers, it is a 'windshield wiper' control or 'windshield wiping system' control. Such a control is therefore subject to the standard's requirements for location, identification and illumination.; We would note that while section S5.2.1 and Table 1 require such control to be identified by the symbol specified for windshield wiping system controls, additional words or symbols may be used at the manufacturer's discretion for purposes of clarity. Since your vehicles would have three windshield wiper controls, you may wish to provide such additional words or symbols to explain the function of each.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1396OpenMr. Jim Lang, President, L and R Enterprises, P.O. Box 2201, Wichita Falls, TX 76307; Mr. Jim Lang President L and R Enterprises P.O. Box 2201 Wichita Falls TX 76307; Dear Mr. Lang: Since the questions raised in your letter of February 15, 1974, ar under the jurisdiction of the National Highway Traffic Safety Administration, Department of Transportation, we have taken the liberty of forwarding it to the General Counsel of that agency.; You can expect to hear directly from that office in the near future. Sincerely, Fred J. Emery, Director of the Federal Register |
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ID: aiam3201OpenMr. J. Kawano, General Manager, U.S. Representative Office, Toyota Motor Co., Ltd., One Harmon Plaza, Secaucus, NJ 07094; Mr. J. Kawano General Manager U.S. Representative Office Toyota Motor Co. Ltd. One Harmon Plaza Secaucus NJ 07094; Dear Mr. Kawano: This responds to your recent request for an interpretation concernin the proper designated seating capacity for the rear seat in several Toyota vehicle models (Corolla Sedan, Corolla Coupe, Corona Sedan and Starlet). You assert that the rear seat hip room in these models ranges from 39.4 inches to 42.6 inches, and ask whether the vehicles would qualify as having only two designated seating positions.; Under the strict measurement technique specified in the amende definition of 'designated seating position' (SAE J1100a), the Toyota vehicle models in question would have the hip room dimensions you state. This is due to the fact that the SAE procedure specifies that hip room is to be the minimum dimension of the seat cushion. The Toyota designs include wheel wells and contoured side paddings at the intersection of the seat back and seat cushion that establish the minimum dimension of the seat. However, these structures only extend out 4 to 5 inches (approximation) from the seat back. If the hip room of the rear seats is measured midway of the seat cushion, all of the designs have greater than 50 inches of hip room, and ostensibly should have three designated seating positions. Nevertheless, since according to the measurement technique specified in the definition these seats have substantially less than 50 inches of hip room, the agency must conclude that the rear seats could qualify as having only two designated seating positions. This opinion is accompanied with several candid remarks, however.; The effective hip room of the Toyota seat designs is much greater tha the approximately 40 inches that is obtained by the technical measuring technique specified in the definition. If two outboard occupants move their hips several inches forward from the seat back in these vehicle designs, the wheel-wells and contoured side paddings are no longer impediments and there is over 50 inches of hip room, as noted above. Moreover, the design of these rear seats is such that use of the center position is 'invited.' There is at least 10 to 12 inches of well-padded hip room at the center portion of the seat between the inboard ends of the two seat belt assemblies installed in the seats. The manufacturer has given no indication that this space is not intended for occupancy. The agency is also concerned that this center position has no belt assembly to secure a child restraint system, particularly since the rear- center seat is statistically the safest position in a vehicle.; Frankly, with the wide center space that is available in these rea seat designs, we do not believe the manufacturer has made a sincere attempt to indicate to vehicle occupants that the seats are intended for use by only two occupants. It would be a simple matter for the manufacturer to make this obvious by use of a fixed armrest or some other impediment to use of the position. Furthermore, we believe that this message can be given to occupants without otherwise compromising the design the manufacturer wishes to achieve. If the manufacturer does not in fact wish to market the vehicles as having three-passenger rear seats, we do not understand why wide, well-padded center positions are present.; Finally, I am enclosing a copy of an earlier interpretation whic discusses the measurement procedure included in the definition of 'designated seating position.' As that interpretation pointed out, the agency will not allow manufacturers to avoid the obvious intent of the definition by finding 'loopholes' in the specified measurement procedure. If designs such as those displayed in the Toyota vehicles persist, without some clear indication that the center position is not to be used, the agency may find it necessary to amend the definition to provide that the hip room measurement is to be taken at the midpoint of the seat cushion. We hope that manufacturers will voluntarily alter designs of this type to conform to the intent of the definition, so that such an amendment is not necessary.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4897OpenMrs. Debby Funk R.R. #1, Box 41A Shirley, IL 61772; Mrs. Debby Funk R.R. #1 Box 41A Shirley IL 61772; Dear Mrs. Funk: This responds to your letter of July 5, l99l, as followup to my letter of June 25. You have asked whether 'it would be illegal for the owner of a vehicle that has a center highmounted stop lamp to install an additional rear window brake light? (anywhere in the back window?)' The answer is that it would not be illegal under Federal law for a vehicle owner to install an additional stop lamp anywhere in the back window, providing that all modifications were performed by the owner. However, the legality of the modification would still be subject to State law. You have also asked 'What is F.M.V.S.S. 108?' That is Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment. It can be found in Title 49 Code of Federal Regulations, as Section 571.108. If you have further questions, please don't hesitate to write. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2040OpenMr. Leonard Barkan, Strick Corporation, U.S. Highway No. 1, Fairless Hills, PA 19030; Mr. Leonard Barkan Strick Corporation U.S. Highway No. 1 Fairless Hills PA 19030; Dear Mr. Barkan: This responds to your July 17, 1975, question whether a used runnin gear assembly can be combined with a new platform to qualify as a 'repaired' trailer that would not have to conform to the requirements for air brake systems on newly-manufactured trailers (Standard No. 121, *Air Brake Systems*). I have enclosed an interpretive letter which should clarify this matter for you. Briefly, the answer is no, if the 'platform' includes the main frame members.; You also asked whether the vehicle must conform to the safety standard if it is assembled for the manufacturer's own use or if it is leased to a third party. Section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(1)(A)) prohibits not only the sale, but also the introduction or delivery for introduction in interstate commerce of vehicles which do not comply with all applicable safety standards in effect on the date of manufacture. Therefore the answer to your question is yes if the vehicle is ever operated on the public streets or highways.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0587OpenMr. George H. Jones, Manager, Alabama Tire Dealers and Retreaders Association, P.O. Box 2851, Birmingham, Alabama 35212; Mr. George H. Jones Manager Alabama Tire Dealers and Retreaders Association P.O. Box 2851 Birmingham Alabama 35212; Dear Mr. Jones: This is in response to your three letters, dated December 1, 1971 December 27, 1971, and January 11, 1972, concerning Motor Vehicle Safety Standard No. 117.; In your letter of December 1, 1971, you enclose a booklet that you hav recently made available which contains your interpretation of Standard No. 117, and ask us to review it. As your letter was written before the amendment of December 23, 1971 (36 F.R. 24814), and the suit in Chicago, it does not, and our reply will not, deal with the changes made by the amendment or the 'stay' ordered by the Court of Appeals. We believe your summary of the standard is correct,but we would recommend that you include in the requirements of paragraph S5.1.1 of Standard No. 117 the treadwear indicator requirements found in S4.2.1(d) of Standard No. 109. This fact is apparently being overlooked by some retreaders, and you may wish to point it out more clearly.; Your letter of December 27 ask whether exposure of cord that ha occurred on casings because of 'chipping' would prevent the casing from being retreaded under S5.2.1. As presently written, S5.2.1 would preclude the retreading of such a casing if what is exposed if ply cord. However, if it is actually 'chafer' fabric, which is a special fabric placed only around the bead, then exposure is permitted.; Finally, with regard to your letter of January 11, I regret that, a you have been told, mike will not be able to attend the Missalaga Conference. He has told me that your organization has done a very responsible job with regard to not only Standard No. 117 but other areas of tire safety as well, and we appreciate your efforts.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2410OpenMr. Warren M. Heath, Commander, Engineering Section, Department of California Highway Patrol, P. O. Box 898, Sacramento, CA, 95804; Mr. Warren M. Heath Commander Engineering Section Department of California Highway Patrol P. O. Box 898 Sacramento CA 95804; Dear Mr. Heath: This is a reply to your letter of September 16, 1976, referencing a opinion letter to you dated October 21, 1969, and asking whether it conflicts with an opinion letter to Ford Motor Company dated 'December 5, 1975'. (The true date of the letter is July 7, 1975, we do not know why your copy is dated otherwise).; The 1969 letter informed you that 'if one compartment or lamp [in multicompartment lamp] meets the photometric requirements [of Standard No. 108] the additional compartments or lamps are considered as additional lamps and are, therefore not regulated by . . . Standard No. 108 except by S3.1.2.'. The letter also stated that 'lamps on a vehicle and not required by this standard are generally subject to regulation by the States.' Our 1975 letter to Ford, on the other hand advised the company in effect that the performance of the entire multicompartment assembly was covered by Standard No. 108, and that section 25950(b), of the California Vehicle Code was preempted by it. You have asked whether our letter to Ford conflicts with our earlier letter to you.; There is no present conflict. In an amendment to Standard No. 10 effective January 1, 1973, (copy enclosed) the agency adopted paragraph S4.1.1.12 and figure 1 which established minimum photometric requirements that must be met by multicompartment tail, stop, and turn signal lamps. The act of establishing requirements for the additional compartments in a multicompartment lamp thus voided the 1969 letter to you and the interpretation to Ford is the correct one.; The Monarch taillamp, therefore, must meet the requirements of Table of standard No. 108 and is not a lamp that is 'in addition to the minimum required number' as that term is used in California Vehicle Code section 25950(b), which appears to have been amended in an effort to include it.; We appreciate your suggestion on an amendment to Standard No. 108 o lens color.; Sincerely,Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3997OpenMr. Rawleigh G. Decker, 18018 134 Avenue, Sun City West, AZ 85375; Mr. Rawleigh G. Decker 18018 134 Avenue Sun City West AZ 85375; Dear Mr. Decker: Thank you for your letter of July 23, 1985, to Secretary Dole, whic was referred to my office for reply. You expressed concern about conflicting state regulations on motor vehicle window tinting and asked about possible Federal regulations on this subject.; Congressman John McCain of Arizona has also recently written our agenc concerning conflicts in state tinting laws. I am enclosing a copy of the Administrator's letter of July 11, 1985, to Congressman McCain explaining what action the agency is taking on the subject of vehicle window tinting. I have also enclosed a (sic) information sheet which explains the Federal requirements on vehicle window tinting.; I hope this information is of assistance to you. If you have an further questions, please let me know.; Sincerely, Stephen P. Wood, Assistant Chief Counsel for Rulemaking |
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ID: aiam2685OpenMr. Robert P. Ducey, Grand Teton Trading Co., Box 2436, Jackson, WY 83001; Mr. Robert P. Ducey Grand Teton Trading Co. Box 2436 Jackson WY 83001; Dear Mr. Ducey: This responds to your letter of September 12, 1977, requestin information concerning the certification requirements for acrylic glazing to be used in motor vehicles. Specifically, you are interested in the separate certification responsibilities of the company that manufactures the acrylic sheets, the company that cuts and shapes the acrylic, and the company that constructs aluminum frames around the acrylic and sells windows to the customized van market.; Paragraphs S6.1 and S6.3 of Safety Standard No. 205, *Glazin Materials*, specify that prime glazing material manufacturers shall certify each piece of glazing that is for use in motor vehicles in accordance with section 114 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381, *et seq*.) and with section 6 of the ANS Z26 standard. These requirements would be applicable to the company from which you buy acrylic sheets, since that company would qualify as a prime glazing material manufacturer.; As a manufacturer or distributor who cuts a section of glazing for us in a motor vehicle, your company would be required to certify its product in the same fashion as your supplier (paragraphs S6.4 and S6.5 of Standard No. 205). Please note, however, that under section 6 of ANS Z26 your company is required to mark any section of glazing that it cuts with the same words, designations, characters, and numerals as the piece of glazing from which it was cut. This means that you would stamp your product with markings identical to the certification markings on the acrylic sheets you purchased.; The company that constructs aluminum around the glazing and sell windows to the customized van market would be required to certify its product in accordance with section 114 of the National Traffic and Motor Vehicle Safety Act. Section 114 provides that an item of motor vehicle equipment (including glazing) may be certified by means of a label or tag on the item of equipment or on the outside of a container in which the equipment is delivered. The label or tag must certify that the item of motor vehicle equipment complies with all applicable motor vehicle safety standards, Standard No. 205 in this case.; Please contact this office if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5140OpenMr. Thomas C. Baloga Manager, Safety Engineering Mercedes-Benz of North America, Inc. One Mercedes Drive P.O. Box 350 Montvale, NJ 07450-0350; Mr. Thomas C. Baloga Manager Safety Engineering Mercedes-Benz of North America Inc. One Mercedes Drive P.O. Box 350 Montvale NJ 07450-0350; "Dear Mr. Baloga: This responds to your letter asking whether th National Highway Traffic Safety Administration (NHTSA) will exercise its discretion not to institute enforcement proceedings with respect to a special seat belt installation in a Mercedes-Benz car owned by a man who weighs approximately 500 pounds. You stated that the owner cannot use the driver-side seat belt because of his large body size and that your special order 12-inch longer belt is still too short. You indicated that your factory has supplied a 30-inch longer seat belt, but that the extra-long belt assembly will not comply with the following aspects of Standard No. 209: --the seat belt will not completely roll up into the B-pillar due to excessive webbing on the spool, --the seat belt has not been tested for retraction spring durability and therefore may not pass the retractor cycle test, --no certification label is attached. As you are aware, our agency is authorized to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. Manufacturers are required by the National Traffic and Motor Vehicle Safety Act (Safety Act) to certify that their products conform to our safety standards before they can be offered for sale. Manufacturers, distributors, dealers and repair businesses modifying certified vehicles are affected by 108(a)(2)(A) of the Safety Act. It prohibits those businesses from knowingly rendering inoperative any elements of design installed on a vehicle in compliance with a safety standard. In certain limited situations in the past where a vehicle must be modified to accommodate the needs of a person with a particular disability, NHTSA has stated that it would consider certain violations of Safety Act provisions as purely technical ones justified by public need, and that it would not institute enforcement proceedings. This is to advise you that we will take this position for the specific factual situation cited above, as we equate the special needs of a 500 pound individual with the needs associated with a disability. I note that we expect manufacturers to provide complying seat belts that are appropriate for the normal range of occupant sizes, including large persons. Mercedes-Benz appears to do this, as it provides a (presumably complying) special order 12-inch longer belt for large persons. We recognize that a 500 pound individual is outside the normal range of occupant sizes. You stated that requests for extra long seat belts are likely to continue and asked whether Mercedes-Benz needs to advise NHTSA of each and every special installation or whether it is sufficient to keep appropriate records of the VIN. I note that if the agency was presented again with the same factual situation, we would expect to make the same decision. However, we would want to be advised of each such special installation. One of the factors behind our position is the special nature of the factual situation. If Mercedes-Benz wanted to provide extra long seat belts on a routine basis, we would expect it to provide a design that fully complies with Standard No. 209. Sincerely, John Womack Acting Chief Counsel cc: Jerry Sonosky, Esq. Hogan & Hartson"; |
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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.