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: aiam3876OpenMr. John S. Cucheran, Vice President, Design and Engineering, Jac Products, Inc., 1901 E. Ellsworth, Ann Arbor, MI 48104; Mr. John S. Cucheran Vice President Design and Engineering Jac Products Inc. 1901 E. Ellsworth Ann Arbor MI 48104; Dear Mr. Cucheran: This is in reply to your letter of November 30, 1984, to Mr. Vinson o this office asking for an interpretation of Motor Vehicle Safety Standard No. 108 *Lamps, Reflective Devices, and Associated Equipment*.; Figure 10 of Standard No. 108 establishes the minimum desig photometrics for center high mounted stoplamps. The test procedure for this particular part of Standard No. 108 which is specified in SAE J186a, stipulates that the 'lamp axis shall be taken as the horizontal line through the light source.' However, I believe that you have misinterpreted the light cone that is involved. The pertinent light cone in this case has its vertex at the photometer and a cross section at the plane of the lamp which encompasses the lens areas. From Drawing A that you have provided, it appears that your rail would interfere with this light cone.; In order to determine if your rack interferes with the photometri requirements, the vehicle must be tested with the rack in position as installed on the vehicle. As the agency has noted before, the photometric requirements do not specify that the entire lens must be visible from each 5 degree down test point. Instead, they specify the intensity of light that must be visible from those points. Therefore, the requirement can be met with a lamp whose lens is partially obscured by a portion of the vehicle when viewed from some of the test points.; We hope that his interpretation is helpful to you. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2334OpenMr. W. Wayne Daniel, Wayne Daniel Truck, Inc., P.O. Box 303, Mt. Vernon, MO 65712; Mr. W. Wayne Daniel Wayne Daniel Truck Inc. P.O. Box 303 Mt. Vernon MO 65712; Dear Mr. Daniel: This responds to your June 18, 1976, request for permission t substitute pre-121 brake components for certain components of the brake systems on trucks and trailers you own that were manufactured in conformity with Standard No. 121, *Air Brake Systems*.; From your description, I assume that you intend to remove portions o the brake system that were installed in satisfaction of the requirements of S5.3.1 of Standard No. 121. Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S 1397(a)(2)(A)) prohibits, with one exception, knowing disconnection of the antilock system by a manufacturer, distributor, dealer, or repair business.; A person that does not fall into these categories is not prohibite from disconnection of the systems. Thus, it would be permissible for you to make such modifications on your own trucks and trailers. Other State or Federal requirements, such as those of the Bureau of Motor Carrier Safety for operation in interstate commerce, may prohibit disconnection. In any case, the NHTSA urges that you not disconnect safety devices without consulting the vehicle manufacturer with regard to the safest configuration of the vehicle.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0309OpenMr. Eisuke Niguma, Manager, Export Vehicle Engineering Dept., Toyo Kogyo Co., LTD., 6047 Fuchu-Machi, Aki-Gun, Hiroshima 730- 91, Japan; Mr. Eisuke Niguma Manager Export Vehicle Engineering Dept. Toyo Kogyo Co. LTD. 6047 Fuchu-Machi Aki-Gun Hiroshima 730- 91 Japan; Dear Mr. Niguma: This is in response to your letter of March 16, 1971, requestin interpretations of several provisions of the Defect Report Regulations, 49 CFR Part 573.; You ask whether a quarterly report containing the information specifie by section 573.5(b) concerning quarterly motor vehicle production must be submitted for calendar quarters during which no defect notification campaign is conducted. This interpretation is correct. A quarterly report containing the production figures and such other information as may be required by section 573.5 must be submitted for each calendar quarter.; You ask whether the first quarterly report required to be submitte pursuant to section 573.5 need cover only the period from August 16, 1971 (the effective date of the regulation) to September 30, 1971. This interpretation is correct.; Finally, you ask whether the term 'submit', as used in section 573.4(b) and 573.5(a), means 'send'. This interpretation is generally correct. The requirements in these sections for the submission of the defect information and quarterly reports would be satisfied by mailing the reports so that they are postmarked within the specified period of time. For example, defect information reports that are mailed to NHTSA must be postmarked not more than 5 working days after a defect in a vehicle has been determined to be safety- related. However, hand-delivered defect information reports must be received by NHTSA not more than 5 working days after such determination.; Please write if we can be of further assistance. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam2553OpenMr. W. G. Milby, Manager, Engineering Services, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Manager Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This is in reply to your letter of March 29, 1977, asking two question about the use of strobe lamps on school buses.; Your first question is whether it is 'legal to install strobe typ warning lamps on school buses?' The answer is yes provided such lamps meet the specific performance requirements in S4.1.4 which incorporates SAE Standard J887 'School Bus Red Signal Lamps.'; You also reference 'certification from our vendor. . . that his syste meets FMVSS if installed according to his instructions.' You have asked if this letter from your vendor is 'adequate documentation upon which we could certify that a bus with such a system meets FMVSS 108?' In an earlier opinion letter on this subject (to Yankee Metal Products Corporation of April 12, 1976) we opined opinion by a professional engineer indicating compliance of a strobe lamp design with SAE J887 provided a basis upon which Yankee could certify that its system meets Standard No. 108. Since you did not enclose the letter from your vendor we cannot comment upon it. However the National Traffic and Motor Vehicle Safety Act requires that a manufacturer exercise due care in insuring that its certification is not false and misleading in a material respect, and you should exercise the same care in this instance that you do with respect to insuring compliance of other items of lighting devices with which your buses are equipped.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam0094OpenMr.. Francesco Palazzi, 11 Direttore, Associazione Nazionale Fra, Industrie Automobilistiche, 10128 - Torino, Italy; Mr.. Francesco Palazzi 11 Direttore Associazione Nazionale Fra Industrie Automobilistiche 10128 - Torino Italy; Dear mr. Palazzi: Thank you for your letter of June 3 to the National Highway Safet Bureau asking 'whether the solution given in the enclosed drawing N. 591-1559 of Ferrari is in line with the requirements' of Federal motor vehicle safety standard No. 211.; This standard states that 'wheel nuts, hub caps, and wheel discs fo use on passenger cars...shall not incorporate winged projections'. The Ferrari plan appears to incorporate such a projection, even though it is recessed. Accordingly the proposed solution by Ferrari does not meet the requirements of Federal standard No. 211.; Sincerely, Joseph R. O'Gorman, Acting Director |
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ID: aiam0581OpenMr. J. Frank Brasher, Salt lake Auto Auction, 460 Orange Street (1900 West), Salt Lake City, Utah 84104; Mr. J. Frank Brasher Salt lake Auto Auction 460 Orange Street (1900 West) Salt Lake City Utah 84104; Dear Mr. Brasher: This is in reply to your letter of January 5, 1972, inquiring whethe you may inlay whitewall rings in black tires. You state that in the process a narrow strip of black rubber around the tire is buffed or ground off and replaced with a strip of whitewall which is bounded or vulcanized to the tire in its place.; Assuming that you are discussing applying this process to new passenge car tires, whether the process is permissible depends upon whether or not it adversely affects the tire's compliance with Motor Vehicle Safety Standard No. 109, 'New Pneumatic Tires,' which prescribed performance requirements for all passenger car tires sold in the United States. A copy of the standard is enclosed.; If after using the process the tire will not comply with Standard No 109, the use of the process is prohibited, and its use can result in the imposition of civil penalties of up to $1,000 per tire and of other sanctions as well (15 U.S.C. 1397(a)(1), 1398, 1399). In addition, it is the responsibility of the one who wishes to use the process to determine whether it will cause the tires to fail the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5279OpenMr. Richard L. Plath Selecto-Flash, Inc. P.O. Box 879 Orange, NJ 07051; Mr. Richard L. Plath Selecto-Flash Inc. P.O. Box 879 Orange NJ 07051; Dear Mr. Plath: This is in reply to your letter of November 15, 1993 to Taylor Vinson of this Office on trailer conspicuity. You ask for confirmation of several points. Initially, we would like to comment as follows on the 4-point procedure you have outlined: '1) A chassis for purposes of the conspicuity requirement shall be considered to be a trailer.' This is correct. Because the chassis is designed for carrying property and for being towed by a motor vehicle, it is a 'trailer' as defined for purposes of compliance with the Federal motor vehicle safety standards. '2) That the total length of the chassis shall be used in computing the 50 percent coverage of high intensity reflective for each individual side.' This is correct. Under S5.7.1.4.2(a) of Standard No. 108, retroreflective tape 'need not be continuous as long as not less than half of the length of the trailer is covered . . . .' '3) In the case of a 48 foot chassis, the law will thus require a minimum of 24 feet of the approved reflective sheeting to be applied to each side. Further, there shall not be more than 18 inches of either red or silver reflective in a continuous strip and that there shall not be an allowed void of more than 48 inches between modules.' This is partially correct. Under S5.7.1.4.2(a), a minimum of 24 feet of reflective material must be applied to the side of a 48-foot trailer. However, S5.7.1.3(a) requires the colors to be red and white, not red and silver. Further, under S5.7.1.3(b), the permissible lengths of the sheeting are expressed as 'each white or red segment shall have a length of 300 mm +/- 150 mm.' We note that 450 mm is slightly less than 18 inches. Finally, Standard No. 108 does not specify any maximum permissible 'void . . . between modules.' Under S5.7.1.4.2(a), the spaces are to be distributed 'as evenly as practicable.' '4) * * * When the chassis is not loaded with a container, the application of 24 feet per side of a 48 foot chassis of evenly spaced reflective modules would comply with the law as we understand it. It would identify the extreme front and rear portions of the chassis. * * *' This is incorrect. Compliance by an unloaded container chassis with the conspicuity requirements is determined as if the container load were in place. S7.5.1.4.2(a) states that 'at the location chosen for conspicuity treatment , the strip shall not be obscured in whole or in part by other motor vehicle equipment or trailer cargo.' Because the container obscures the gooseneck, the conspicuity treatment mandated by Standard No. 108 cannot identify the extreme front portion of the chassis. Its front termination point will be behind the gooseneck, at a point where it is not obscured by the container. You have correctly stated this with respect to a loaded chassis but it applies to the unloaded chassis as manufactured: '. . . the entire 24 feet (50 per cent of length) shall be applied behind the gooseneck. In general this would mean that the rear 40 foot portion of the chassis would contain the 24 feet of reflective modules. Further we understand that the 50 percent requirement would be satisfied and that additional modules would not have to be applied to the gooseneck.' You conclude that a gooseneck chassis traveling without its container would be in violation of Standard No. 108 if its gooseneck were not marked 'creating a hazard and would violate the requirement stating that a void of no more than four feet is allowable.' You also ask ' i s there a benefit in applying the additional 4 feet of reflective within the rear 40 foot portion of the chassis?' As explained previously, Standard No. 108 does not require marking of the gooseneck of a container chassis, and there is no requirement limiting the spacing between segments of retroreflective material. We believe that the desired conspicuity of the trailer will be maintained by requiring the additional 4 feet of sheeting on the chassis behind the gooseneck when the gooseneck itself will be obscured with the container in place. Standard No. 108 does not prohibit a manufacturer from applying conspicuity treatment to the 8-foot gooseneck of a 48 foot trailer if it wishes to do so, however, the manufacturer is still required to apply not less than 24 feet of material in the 40-foot section behind the gooseneck. We shall be pleased to answer the following four questions you have also raised: '1) Will we need to apply 24 feet of stripping on a 48 foot chassis behind the gooseneck plus an additional 4 feet on the gooseneck?' You will have to apply 24 feet of stripping on the portion of a 48-foot chassis that lies behind the gooseneck, but you are not required to mark the gooseneck. '2) Since a chassis is considered to be treated as a trailer, shouldn't we apply the 24 feet evenly spaced from the extreme rear and front portions of the chassis?' As explained previously, the 24 feet of material is to be applied behind the gooseneck. If you wish to apply evenly spaced conspicuity treatment that includes the gooseneck, you may do so, as long as at least 24 feet of it is behind the gooseneck. '3) Is a tire considered a legal obstruction? If so, can we deduct the distance behind the tire from the 50 percent coverage?' Yes, a tire is 'motor vehicle equipment' within the meaning of S5.7.1.4.2(a) forbidding the obscuring of conspicuity treatment. No, you may not deduct the length of the area obscured by the tire from the 50 per cent coverage. You must include it in the 50 per cent computation. Thus, if a tire would obscure 3 feet of conspicuity material on the side of a 48 foot gooseneck trailer, the manufacturer must apply 24 feet of material in the 37 feet that is behind the gooseneck which is not obscured. We note in passing that the prints submitted for our review by J.Z. Peepas of Selecto-Flash depict conspicuity treatment that is above the top of the tire and apparently not obscured by it. '4) We anticipate that the slide mechanism on an extendable chassis will scrape the reflective film off the chassis. Is the operator then subject to penalties? How will the operator be able to avoid these penalties since they have no control over this process?' You are not required to place conspicuity treatment on the extendable portion of the chassis provided that not less than half of the length of the trailer is covered when the conspicuity treatment is placed elsewhere. In the event that conspicuity treatment is placed on the extendable portion and is damaged when the trailer is in use, the operator will not be subject to any penalties of this agency. Federal regulations governing the use of commercial vehicles in interstate commerce are issued by another agency of the Department of Transportation, the Federal Highway Administration (FHWA). The FHWA requires that vehicles manufactured on or after March 7, 1989, meet the requirements of Standard No. 108 in effect on the date of manufacture of the vehicle (49 CFR 393.11). Therefore, maintenance of the conspicuity treatment on trailers manufactured on or after December 1, 1993, is required by the FHWA. If you wish to write FHWA on this topic, you may address James E. Scapellato, Director, Office of Motor Carrier Standards, FHWA, Room 3107, 400 Seventh Street, SW, Washington, D.C. 20590. The individual states may have regulations in this area as well. We are unable to advise you on State requirements, and suggest that you consult the American Association of Motor Vehicle Administrators, 4600 Wilson Blvd., Arlington, Va. 22203. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam4891OpenMessrs. Steven M. and Morris G. Healy P.O. Box 73 Worthington, MA 01098-0073; Messrs. Steven M. and Morris G. Healy P.O. Box 73 Worthington MA 01098-0073; Dear Messrs. Healy: This responds to your letter of June 5, l99l, t Richard Van Iderstine of this agency, asking for an opinion as to the legality of your device that attaches monitoring lights to bug deflectors 'and/or to other appropriate mounting areas on vehicles.' As you state it, the primary purpose of the device is to 'bring indicator lights up and into the line of vision of the vehicle operator.' You specifically mention the turn signal and upper beam indicators ('or other appropriate applications desired by the operator).' You mention that the existing indicator lights on the dashboard are left undisturbed. As bug deflectors or shields are accessory equipment sold in the aftermarket, it is clear that you do not intend your device to be original equipment offered by the vehicle manufacturer. The Federal statute governing the manufacture of motor vehicles and motor vehicle equipment is the National Traffic and Motor Vehicle Safety Act. There is no regulation or standard under this Act that relates to the manufacture and sale of your device. We must, however, add a cautionary note relating to the use of your device by its purchaser. The Act prohibits any 'manufacturer, distributor, dealer, or motor vehicle repair business' from rendering 'inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle . . . in accordance with an applicable Federal motor vehicle safety standard.' You have assured us that the existing indicator lamps are not affected. However, one of the requirements of the lighting standard (Standard No. 108) that applies to motor vehicles is that accessory equipment not 'impair the effectiveness' of the lighting equipment required by the standard. We regard the potential to create confusion as the potential to impair the effectiveness of lighting equipment. It does not appear that the turn signal indicator portion of your device, operating in tandem with the turn signals, would create confusion. Likewise, the upper beam indicator would be too small to be perceived by an oncoming car at any great distance. However, you have added qualifications to your letter ('other appropriate mounting areas on vehicles' and 'other appropriate applications desired by the operator') that require us to advise you of the statutory prohibition. The prohibition does not affect vehicle owners, and if you intend the device to be installed by them, you may disregard the foregoing. However, in any event, the use of the device is also subject to the laws of any State in which it will be used. We are unable to advise you on these laws, and suggest that you write for an opinion the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2046OpenMr. Frank Hardy, Owner, The Hardy Heater Company, 9609 Dixie Highway, Louisville, KY 40272; Mr. Frank Hardy Owner The Hardy Heater Company 9609 Dixie Highway Louisville KY 40272; Dear Mr. Hardy: This is in response to your letter of July 30, 1975, in which yo inquire as to any rules and regulations to which you may be subject with respect to your pre-heater defroster. Your letter was referred to this office by the Environmental Protection Agency.; We assume, from the material submitted with your letter, that you pre-heater is sold for installation in used cars and supplements the vehicle's existing defrosting system. If our assumption is incorrect, please advise us. If your pre-heater is installed in a motor vehicle prior to its first purchase or if it replaces an existing defrosting system, you will be subject to regulations in addition to those mentioned in this letter.; The National Traffic and Motor Vehicle Safety Act provides that manufacturer, dealer, distributor, or repair shop may not render inoperative any safety device or design in a motor vehicle after its first purchase by the owner. this means that the installation of the pre-heater must not take the vehicle out of compliance with an applicable Federal Motor Vehicle Safety Standard. The standard with which you will likely be most concerned is Standard No. 103, *Windshield Defrosting and Defogging Systems* (copy enclosed).; In addition, if the fuel used in your pre-heater has a boiling poin greater than 32 degrees Fahrenheit, you must ensure that the pre-heater fuel system complies with Standard No. 301, *Fuel System Integrity* (copy enclosed).; Thank you for your interest in motor vehicle safety. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5629OpenJonathan P. Reynolds, Esq. Cosco, Inc. 2525 State St. Columbus, IN 47201; Jonathan P. Reynolds Esq. Cosco Inc. 2525 State St. Columbus IN 47201; "Dear Mr. Reynolds: This responds to your letter asking us to confir that we consider your submission, dated August 3, 1995, as a timely petition for reconsideration of a final rule published July 6, 1995 (Docket No. 74-09, Notice 42). You enclosed a copy of a Federal Express document to show that your submission was received by NHTSA within the time period provided for such petitions under 49 CFR 553.35. The Federal Express document, which shows the signature of an agency employee, supports a finding that your submission was timely filed. NHTSA is processing your submission as a petition for reconsideration of the subject rule. If you have any further questions about your petition, please contact Ms. Deirdre Fujita of my staff at (202) 366-2992. Sincerely, John Womack Acting 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.