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: aiam4978OpenMr. Masashi Maekawa Director, Technical Division Ichikoh Industries, Ltd. 80 Itado, Isehara City Kanagawa, 259-11, Japan; Mr. Masashi Maekawa Director Technical Division Ichikoh Industries Ltd. 80 Itado Isehara City Kanagawa 259-11 Japan; "Dear Mr. Maekawa: This responds to your letter of February 21, 1992 asking for a clarification of our letter of December 18, 1991. In that letter we discussed 'a combination tail/stop lamp that would be mounted on the deck lid ('Lamp B') immediately adjacent to a combination tail\stop lamp that is mounted on the vehicle body ('Lamp A')'. You informed us that each lamp complied with the requirement for effective projected luminous lens area, but that neither complied with photometric requirements. You asked whether Ichikoh could consider the two adjacent lamps as one lamp for purposes of measuring photometrics. We replied that it was not possible to consider the two lamps as one, and that we regarded the lamp that was on the vehicle body as the one that should be designed to conform to Standard No. 108. You have asked whether this advice is consistent with an interpretation given Mazda on June 28, 1985, with respect to a similar design. That letter informed Mazda that compliance of the design would be judged with the vehicle in its normal driving position, thereby implicitly agreeing that the two lamps could be considered one for photometric purposes. The difference in the interpretations originated in the way each manufacturer described its design. Ichikoh referred to its design as two adjacent lamps. Mazda described its configuration as a (single) lamp constructed so that a portion of it is fixed to the body and a portion on the decklid. Our review of the two designs shows that they are essentially similar, and that the Mazda design comprises, in fact, two adjacent lamps. As it was not our intent to change the earlier interpretation, we confirm that the June l985 interpretation remains valid, and that the December 1991 letter is overruled to the extent that it is inconsistent with it. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0192OpenMr. 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: Thank you for your letter of December 8, 1969, concerning alternat flashing of side marker lamps with turn signal lamps.; Alternate flashing sidemarker lamps are permitted in paragraph S3.5 o Motor Vehicle Safety Standard No. 108 for signaling purposes, however, they must not impair the effectiveness of the turn signal lamps as required in paragraph S3.1.2.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam2455OpenMr. B. R. Weber, Executive Vice President, Wesbar Corporation, Box 577, West Bend, WI, 53095; Mr. B. R. Weber Executive Vice President Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Weber: This is in reply to your letter of October 28, 1976, asking severa questions with respect to that portion of paragraph S4.4.1 of Motor Vehicle Safety Standard No. 108 which prohibits the optical combination of clearance and tail lamps. You have also expressed your concern, in a recent telephone conversation with Mr. Vinson of my staff, about the ACUTEK interpretation of October 22, 1976, to be discussed below.; The distinction between the hypothetical lamp in Question 2 of you letter of September 7, 1976, and the Acutek lamp is that there is no opaque barrier wall in the former, separating the tail lamp bulb and the clearance lamp bulb, while in the latter the barrier rises to the base of the bulb. Since Standard No. 108 does not require separate compartments (i.e., an opaque barrier) for tail lamps and clearance lamps, it is obvious that the prohibition against optical combination means that (a) a single bulb may not perform both functions and (b) a single bulb must not be perceived as performing both functions. This was the rationale behind Mr. Driver's advice to Acutek that the available data indicated 'that when the tail lamp bulb [on the Acutek lamp] is activated independently from the clearance lamp bulb, and vice versa, there is no appreciable amount of incidental light emitted from the lens of the clearance lamp,' and that 'the amount of light 'spill' appears to be so small that it would not be interpreted (by a driver following the vehicle on which it is installed) as illuminating the lens of the tail lamp when operated in the clearance lamp mode, and vice versa.'; If you apply this general principle to the questions you asked then think you will have the answers. The principle is necessarily dependent upon the candlepower output of any lamp to which it is applied, a value not given in your questions. Thus, the principle cannot be quantified and the determination of the extent of light spill is necessarily subjective, and certification is dependent upon a manufacturer's good faith in attempting to achieve compliance.; After reviewing this matter I must admit that I am curious as to th safety rationale behind the prohibition. Paragraph S4.4.1 had its genesis in a similar provision in Bureau of Motor Carrier Safety regulations (49 CFR 393.22(b)(3), formerly 393.22(c)) and was adopted in conformance with it. The Society of Automotive Engineers, however, does not prohibit combining these lamps. If clearance lamps are mounted below 72 inches--the maximum allowable mounting height for tail lamps--it may be that they could be combined with tail lamps, without any detriment to safety, and at a saving to the consumer. Perhaps you would like to comment on this.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0468OpenMr. Fredrick A. Stewart, Vice President, Safety and Quality Assurance, American Motors Corporation, 14250 Plymouth Road, Detroit, MI, 48232; Mr. Fredrick A. Stewart Vice President Safety and Quality Assurance American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Stewart: This is in response to your recent telephone inquiry as to whether th recent amendment of Standard 215, Exterior Protection, requires that vehicles meet the photometric requirements of Standard 108 after being subjected to the Standard 215 impacts.; S5.3.1 of Standard 215 reads: >>>'Each lamp or reflective device, except license plate lamps, shal be free of cracks and shall comply with the applicable requirements of Motor Vehicle Safety Standard No. 108.'<<<; S4.3.1.1 of Standard 108 reads in relevant part: >>>'Each lamp and reflective device shall be located so that it meet the visibility requirements specified in any applicable SAE Standard or Recommended Practice. *In addition, no part of the vehicle shall prevent the device from meeting the photometric output at any test point specified* in any applicable SAE Standard or Recommended Practice.'(Emphasis supplied.)<<<; Thus, although the actual photometric tests may be considered 'benc test', that is, tests whose procedures include removing the devices from the vehicle, the above provision of Standard 108 requires that the configuration of the vehicle external to the devices not prevent them from meeting the photometric requirements. The test procedures themselves require the devices to be placed in their actual orientation on the vehicle. Therefore, the provision in Standard 215 that the lamps and reflective devices shall meet all the requirements of Standard 108 after the impacts includes the photometric requirements.; Sincerely, Robert L. Carter, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam5390OpenMr. Paul L. Anderson President Van-Con Inc. P.O. Box 237 Middlesex, NJ 08846-0237; Mr. Paul L. Anderson President Van-Con Inc. P.O. Box 237 Middlesex NJ 08846-0237; Dear Mr. Anderson: This responds to your letter of May 19, 1994 requesting an interpretation of the requirements of S5.5.3(c) of Standard No. 217, Bus Emergency Exits and Window Retention and Release. Section S5.5.3(c) reads: Each opening for a required emergency exit shall be outlined around its outside perimeter with a minimum 3 centimeters wide retroreflective tape, either red, white or yellow in color ... Your letter states that you are unable to continuously outline the perimeter of the rear emergency doors on your school buses due to the proximity of door hinges, tail light lenses, and a rubber gasket between the bottom edge of the door and the bumper. You ask: Would we be in compliance with Reflective Tape requirements of FMVSS 217 if we put a continuous strip of tape across the top of both Emergency Rear Doors on the roof cap above the doors and down the left and right side of the double door opening with breaks in the tape for door hinges & tail light lenses. This would outline the Emergency Rear Doors on three sides. No tape would be put across the bottom? As an alternative, if the above is not acceptable, could we put tape across the bottom on the doors? As explained below, your planned placement for the top and sides of the door, and your alternative placement for the bottom of the door would be acceptable. In a July 7, 1993 letter to the Blue Bird Body Company, NHTSA stated: NHTSA interprets S5.5.3(c) to allow interruptions in the tape necessary to avoid and/or accommodate curved surfaces and functional components, such as rivets,rubrails, hinges and handles, provided, however, that the following requisites are met. In the November 2, 1992, final rule, NHTSA indicated that the purpose of the retroreflective tape would be to identify the location of emergency exits to rescuers and increase the on- the-road conspicuity of the bus. Accordingly, the retroreflective tape may have interruptions if they satisfy both of these purposes. The occasional breaks in the tape you described would not appear to negatively affect a rescuer's ability to locate the exits, or reduce the conspicuity of the bus. However, the tape should be applied as near as possible to the exit perimeter... When rivets are present, NHTSA will defer to a manufacturer's decision to apply the retroreflective tape immediately adjacent to the rivets, rather than over the rivets, if the manufacturer decides that this will increase the durability of the tape. According to this July 1993 letter, interruptions in the retroreflective tape to avoid and/or accommodate hinges (such as the hinge on the side of the rear emergency door) and other functional components are permitted if the interruption does not negatively affect a rescuer's ability to locate the exits, or does not reduce the conspicuity of the bus. NHTSA considers tail light lenses to be 'functional components' which do not have to be covered by the retroreflective tape. (Indeed, placement of the tape on the tail light lense could affect the efficacy of the light.) The interruptions in the tape for these components would not appear to negatively affect a rescuer's ability to locate the exits, or reduce the conspicuity of the bus. Thus, the interruptions are permitted for the tape along the sides of your door. With regard to the bottom of your door, based on the pictures provided with your letter, it appears that there is no location available for the placement of retroreflective tape outside of the door's bottom edge. Since not outlining an entire side of an exit might affect a rescuer's ability to locate the exit and would reduce the conspicuity of the exit, the bottom side of the door must be marked with the retroreflective tape. In this situation, NHTSA interprets S5.5.3(c) as allowing placement of the retroreflective tape on the door itself, as near as possible to the lower edge of the door. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam5628OpenMr. Lawrence A. Beyer Attorney at Law 674 Lake Road Webster, NY 14580; Mr. Lawrence A. Beyer Attorney at Law 674 Lake Road Webster NY 14580; Dear Mr. Beyer: This responds to your August 28, 1995, 'Petition fo Exemption for Inconsequential Defect or Noncompliance'. You state that 'the noncompliance relates to' 49 CFR Part 592. The effect of an inconsequentiality determination is to relieve a manufacturer of its obligation to notify and remedy when a noncompliance with a Federal motor vehicle safety standard or a safety related defect is determined to exist. The failures you attributed to your client as a registered importer under part 592 do not encompass a failure to bring vehicles into compliance with the Federal motor vehicle safety standards, or the existence of a safety related defect in vehicles that it has imported. Therefore, there is no legal basis for your 'petition'. Please read 49 U.S.C. 30118 and 30120, and 49 CFR Part 556. The proper forum for your arguments is in response to any penalty the agency may propose to impose on your client for its failure to meet the requirements of Part 592. If you have any questions, you may call Taylor Vinson (202-366-5263). Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2417OpenMr. N. Harada, Yokohama Tire Corp., 1530 Church Road, Montebello, CA 90640; Mr. N. Harada Yokohama Tire Corp. 1530 Church Road Montebello CA 90640; Dear Mr. Harada: I am writing to confirm your October 15, 1976, telephone conversatio with Mark Schwimmer of this office, concerning the effective dates of the Uniform Tire Quality Grading Standards (UTQGS) (49 CFR Part 575.104).; As Mr. Schwimmer explained, (i) the National Highway Traffic Safet Administration has not yet established new effective dates for the UTQGS regulation, (ii) when the new effective dates are established, they will be announced in the Federal Register, and (iii) the interval between the announcement of the effective dates and the dates themselves will be sufficient to allow manufacturers to prepare for compliance with the regulation.; For your convenience, an information sheet entitled 'Where to Obtai Motor Vehicle Safety Standards and Regulations' is enclosed.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam1391OpenMr. Bernard Belier, U.S. Resident Engineer for Maserati, S.p.A., Officine Alfieri Maserati, S.p.A., Modena, Italy; Mr. Bernard Belier U.S. Resident Engineer for Maserati S.p.A. Officine Alfieri Maserati S.p.A. Modena Italy; Dear Mr. Belier: This is in replay to your letter of January 22, 1974, asking whethe paragraph S4.3.1 of Motor Vehicle Safety Standard No. 108 precludes the mounting of rear lamps in a transparent 'Lexan' panel 'not involved in the driver's rearward vision.'; Paragraph S4.3.1 states in pertinent part that '. . . each lamp . . shall be securely mounted on a rigid part of the vehicle other than glazing that is not designed to be removed except for repair . . . .' The 'glazing' referred to is the glazing regulated by Standard No. 205, and refers generally to glazing used in windshields, windows, doors, and interior partitions. Accordingly, Standard No. 108 does not preclude the mounting of rear lamps in the 'Lexan' panel.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4469OpenMr. Jay Costa Assistant Procurement Specialist Municipality of Metropolitan Seattle Exchange Bldg., 821 Second Ave. Seattle, Washington 98104; Mr. Jay Costa Assistant Procurement Specialist Municipality of Metropolitan Seattle Exchange Bldg. 821 Second Ave. Seattle Washington 98104; "Dear Mr. Costa: I am responding to your letter seeking a interpretation of Standard 217, Bus Window Retention and Release (49 CFR /571.217). Specifically, you expressed concern that some transit system passengers are opening the rear emergency exits on your public transit vehicles. Apparently, some passengers open these emergency exits to commit acts of vandalism. You state that 'in the interest of safety the rear emergency window (in these vehicles) should be removed and replaced with a non-operable type window.' You asked whether Standard 217 would prohibit your body shop from modifying your transit buses in this manner. Assuming that your body shop does not hold itself out to the public as a business that repairs motor vehicles for compensation, the shop would not be prohibited from modifying the buses as you describe. Under paragraph S5.2.1 of Standard 217, buses that have a gross vehicle weight rating of 10,000 pounds or more (such as your transit buses) must have at least one rear emergency exit, unless the configuration of the bus precludes installing an accessible rear exit. The manufacturer of your buses has stated that the bus configuration does not preclude installing an accessible rear exit. Therefore, your manufacturer must deliver buses that are equipped with a rear emergency exit. On the other hand, your repair shop is subject to different considerations. Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(2)(A)) prohibits certain commercial establishments from 'rendering inoperative' any device or element of design included on or in a vehicle in compliance with an applicable safety standard. In your example, the rear emergency exit is an element of design included in the buses in compliance with an applicable safety standard, and removing these exits would render inoperative that element of design. However, the 'render inoperative' prohibition applies only to manufacturers, distributors, dealers, or motor vehicle repair businesses. A 'motor vehicle repair business' is defined in /108(a)(2)(A) as 'any person who holds himself out to the public as in the business of repairing motor vehicles or motor vehicle equipment for compensation.' Please note that the 'render inoperative' provision does not apply to a vehicle owner. The vehicle owner may modify his or her vehicle without violating any Federal requirements, irrespective of whether the modification affects the vehicle's compliance with a safety standard. Assuming that your transit system body shop does not hold itself out to the public as being in the business of repairing motor vehicles for compensation, it can make the modification you describe without violating any Federal requirements. The problem you describe apparently involves the design for releasing the kind of emergency window exit in your vehicles. Standard 217 does not require a specific design for releasing an emergency exit. Rather, the Standard sets out a ceiling for the magnitude of force necessary to release the exit, and a required direction for applying the release force. The transit system could replace the 'operable' rear emergency window with a push-out window or other type of design that would still meet the release requirements of Standard 217, yet make it difficult or impossible for a passenger to commit the acts of vandalism you describe. Please note that the purpose of our emergency exit requirements for buses is to facilitate quick and safe rider exit in the event of an emergency. Though nothing prohibits you from modifying the vehicles to close off the rear emergency exit, I urge you to give your fullest consideration to the implications of making this modification. It is NHTSA's position that compliance with Standard 217 is the safest way to facilitate vehicle exit in an emergency, and it is my opinion that you needn't eliminate the rear window exit to resolve your problem. Further, you might want to check with the State of Washington to learn if it prohibits modifications that would make your transit buses no longer comply with Standard 217. I hope you find this information helpful. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam0979OpenMr. Robert L. Scates, R.R. No. 1, Box 168, Prairie Farm, WI 54762; Mr. Robert L. Scates R.R. No. 1 Box 168 Prairie Farm WI 54762; Dear Mr. Scates: This is in reply to your letter of January 6, 1973, requestin information on requirements regarding the manufacture of truck-mounted campers. You specifically mention requirements dealing with wiring.; There are several Federal requirements applicable to campers. Camper are items of motor vehicle equipment under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 *et seq*.) and are required to conform to certain motor vehicle safety standards and regulations. Briefly, each camper must meet requirements applicable to the glazing materials (glass and plastics used in windows, doors, and interior partitions) used in the camper (Federal Motor Vehicle Safety Standard No. 205, 'Glazing Materials', 49 CFR 571.205). Each slide-in camper must, in addition, have affixed to it a label that indicates among other things its loaded weight. (Federal Motor Vehicle Safety Standard No. 126, 'Truck-Camper Loading', 49 CFR 571.126). All campers must also be certified in accordance with Section 114 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1403) as conforming to applicable standards. Each camper manufacturer must submit certain information concerning his company pursuant to NHTSA regulations, 'Manufacturer Identification' (49 CFR Part 566). You may obtain copies of NHTSA standards and regulations as explained on the enclosure.; We understand that certain states also have requirements, includin requirements for wiring, that apply to campers. Information regarding these requirements should be obtained from State authorities. Trade associations that represent recreational vehicle manufacturers may be of help in obtaining this information.; Yours truly, Richard B. Dyson, Assistant 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.