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: aiam0667OpenMr. Harry O. Youngberg, Tiny's Tire Center, 10805 Pacific Avenue, Tacoma, WA 98444; Mr. Harry O. Youngberg Tiny's Tire Center 10805 Pacific Avenue Tacoma WA 98444; Dear Mr. Youngberg: Thank you for your recent letter regarding tire identification an recordkeeping, and your suggestions for promotion of safety on the highways.; As you know the Congress set forth the requirements for tir identification and recordkeeping as a part of the National Traffic and Motor Vehicle Safety Act of 1966, amended May 22, 1970. The Safety Act specifically places responsibility for tire identification and recordkeeping upon the manufacturer with the assistance of dealers and distributors. We believe Regulation Part 574 implements this mandate of the Congress in an effective and workable manner. Hopefully it will prove to be a protective measure to the great majority of conscientious industry members who are maintaining high safety standards in their products.; This Administration, by authority of the National Highway Safety Act o 1966, is also deeply involved in a program of traffic safety standards. Periodic Motor Vehicle Inspection is the first standard in the program. Details concerning the standard are contained in the Highway Safety Program Manual Volume I, copy enclosed.; Another standard in the program entitled 'Alcohol in Relation t Highway Safety' is described in the Highway Safety Program Manual Volume 8, copy enclosed. As you know, State and local enforcement plays a major role in the success of this type of program. We acknowledge, however, that much work at the Federal level is yet to be done in this area of safety.; Standardizing automotive switches and controls is related to acciden avoidance and is covered in the series-100 of Federal motor vehicle safety standards. Please note Standards No. 101 and No. 102 in the enclosed publication.; With regard to consumer information and protection, special attentio is being given to this subject by the White House's Office of Consumer Affairs. We are enclosing a pamphlet that contains an index of Federal publications on how to buy and use consumer products.; Your interest in consumer safety and protection is very muc appreciated.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam1975OpenMs. Connie R. Gale, Chrysler Corporation, P.O. Box 1919, Detroit, MI 48231; Ms. Connie R. Gale Chrysler Corporation P.O. Box 1919 Detroit MI 48231; Dear Ms. Gale: This is in response to your letter of June 11, 1975, requesting a interpretation of Part 567 with respect to whether or not Chrysler should affix a certification label to an incomplete vehicle prior to shipping the vehicle to an outside vendor for body work.; It appears from your letter that there is some misunderstandin regarding the certification requirements applicable to manufacturers of incomplete vehicles. Section 567.4, to which you refer in your letter, is not applicable to vehicles manufactured in two or more stages. However, Section 567.5(c) provides that if an incomplete vehicle manufacturer assumes legal responsibility for all duties and liabilities imposed by the Act, as provided for in Section 568.7(a), then the incomplete vehicle manufacturer must ensure that a certification label is affixed to the final vehicle with the incomplete vehicle manufacturer's name after the words 'MANUFACTURED BY' or 'MFD BY'. The date to be included on this label must follow the words 'INCOMPLETE VEHICLE MANUFACTURED' or 'INC VEH MFD' and is the '[m]onth and year in which the original manufacturer of the incomplete vehicle performed his last manufacturing operation on the incomplete vehicle . . ..' (Section 567.5(a)(4)). The date as of which the manufacturer certifies that the vehicle conforms to applicable safety standards is any date no earlier than the manufacturing date of the incomplete vehicle and no later than the date of completion of final-stage manufacture. (Section 567.5(a)(7)).; The regulations do not specify a date on which the certification labe must be affixed. However Section 114 of the Traffic Safety Act provides that the label must be on the vehicle at the time of its delivery by the manufacturer to the distributor or dealer.; We trust that the above explanation will provide you with the guidanc that you need. If you have any further questions, please let us know.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam3948OpenMr. M. Mizuguchi, Ashimori Industry Co., Ltd., 12, 4-chome Yokobori, Higashi-ku, Osaka, Japan; Mr. M. Mizuguchi Ashimori Industry Co. Ltd. 12 4-chome Yokobori Higashi-ku Osaka Japan; Dear Mr. Mizuguchi: Your letter of February 28, 1985, was forwarded to my office for reply You asked whether the webbing attached to a buckle you intend to use must meet the webbing width requirement of S4.2 of Standard No. 209, *Seat Belt Assemblies*. The webbing is enclosed in a plastic sheath. As explained below, the webbing must meet the width requirement of the standard.; S4.2 of Standard No. 209 provides that the 'width of the webbing in seat belt assembly shall be not less than 1.8 inches, except for portions that do not touch a 95th percentile adult male with the seat in any adjustment position and the seat back in the manufacturer's nominal design riding position when measured under the conditions prescribed in S5.1(a).' The purpose of S4.2 is to ensure that belt webbing which comes into contact with an occupant has a minimum width that spreads the load imposed by the belt in a crash. By requiring webbing to spread rather than concentrate the load, the belt width requirement helps minimize the possibility of webbing-caused injury.; In the case of your design, the webbing is enclosed in tightly-fitting plastic sheath. You state that the webbing/sheath combination can come into contact with an occupant. The sheath enclosed with your sample is made from an easily deformable plastic. Thus, when the crash loads are imposed by the belt, the sheath will deform and the crucial factor in concentrating the load on an occupant is the width of the belt. Since the webbing/sheath combination can contact and impose crash loads on an occupant, the agency concludes that the webbing must meet the minimum width requirement of S4.2.; If the webbing were encased in a reinforced sheath that did no appreciably deform under loading, the agency would consider both the width of the webbing and its encasing sheath in determining whether the requirement of S4.2 was met.; I have enclosed the sample of your product sent with your letter. I you have any further questions, please let me know.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam5465OpenSamson Helfgott, Esq. Helfgott & Karas, P.C. 60th Floor Empire State Building New York, NY 10118-6098 Re: Your Ref. No.: 12.065; Samson Helfgott Esq. Helfgott & Karas P.C. 60th Floor Empire State Building New York NY 10118-6098 Re: Your Ref. No.: 12.065; "Dear Mr. Helfgott: We have received your letter to John Womack, th former Acting Chief Counsel of this agency, responding to his letter to you of July 20, 1994. Thank you for enclosing a copy of his letter for ready reference. Our previous letter to you was without the benefit of the diagram of the Caine system which you have now enclosed. The system is intended to be placed 'along the side of trucks and other vehicles.' It consists of three red lamps mounted over three amber (yellow) ones, the array installed between the amber front side marker lamp and the red rear side marker lamp. In normal operation the amber lamps are used as 'running lights' but will be turned off when the red lamps are illuminated in a steady burning state upon application of the brake pedal. The three amber lamps will flash to indicate that the vehicle is turning. All six lamps will flash when the hazard indicator switch is on. If the turn signal is on and the driver's foot is on the brake pedal, the amber lamps will flash while the red ones illuminate in a steady burning state. At 32 candela, the turn signal lamps will be at a higher intensity than the running lamps which operate at 3 to 5 candela. These are within NHTSA specifications. You ask whether this system will be in violation of Standard No. 108. This office has corresponded with you on lighting matters on a number of occasions and you are well aware that supplementary lighting equipment is prohibited as original equipment only if it impairs the effectiveness of lighting equipment that is required by Standard No. 108. This determination is to be made by the manufacturer or dealer who installs the equipment and NHTSA will not question it unless it is clearly erroneous. Sincerely, Philip R. Recht Chief Counsel"; |
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ID: aiam0237OpenMr. Thomas J. McKnight, President, Fleet Cap'n Trailers, Inc., P. O. Box 508, New Bern, NC 28560; Mr. Thomas J. McKnight President Fleet Cap'n Trailers Inc. P. O. Box 508 New Bern NC 28560; Dear Mr. McKnight: This is in reply to your letter of April 29, 1970, to Mr. Rodolfo A Diaz, Acting Associate Director, Motor Vehicle Programs, concerning the location of rear lamps on various models of your trailers.; From a review of the sketch attached to your letter, it appears tha the tail, stop and turn signal lamps mounted on the trailer frame rearward of the fenders will meet the location requirements specified in Table IV of Federal Motor Vehicle Safety Standard No. 108. However, Standard No. 108, by reference to SAE Standard J588d, also requires that '---visibility of the front turn signal to the front and the rear signal to the rear shall not be obstructed by any part of the vehicle throughout the photometric test angles for the lamps.' The photometric test angles for turn signal lamps are specified in Table 2 of SAE Standard J575c. From your sketch it appears that the required visibility of the turn signal lamps, when mounted in the proposed location, would be partially blocked by the framework of the trailer. Mounting the lamps on the rear crossmember may therefore be necessary to provide the required unobstructed visibility.; For your information I am enclosing copies of Standard No. 108, SA Standard J588d and SAE Standard J575c.; Sincerely, Roger H. Compton, Director, Office of Operating Systems Motor Vehicle Programs; |
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ID: aiam5035OpenHerr Tilghman Spingler Robert Bosch GmbH Dept K2/ELS 11 Postfach 13 42 D-4710 Reutlingen Germany; Herr Tilghman Spingler Robert Bosch GmbH Dept K2/ELS 11 Postfach 13 42 D-4710 Reutlingen Germany; "FAX (49)7121-1792 Dear Herr Spingler: This responds to your FAX o July 9, 1992, asking for a 'quick answer' to your question regarding the aim of replaceable bulb headlamps. Specifically, you ask whether the requirement of 'a vertical aim range of +/-4 degrees and a horizontal aim range of +/- 2.5 degrees' means 'that a headlamp has to meet both ranges in addition, i.e. 2.5 degrees horizontal at a full range of 4 degrees vertical and vice-versa?' The requirements to which you refer are found in paragraphs S7.7.3 and S7.7.4 of Standard No. 108. Paragraph S7.7.3 requires in pertinent part that 'When a headlamp system is tested in a laboratory, the range of its vertical aim shall be not less than +/- 4 degrees from the nominal correct aim position for the intended vehicle application.' Paragraph S7.7.4 requires that 'When a headlamp system is tested in a laboratory, the range of its horizontal aim shall be not less than 2.5 degrees from the nominal correct aim position for the intended vehicle application.' We call your attention to paragraph S7.7.2.2. With respect to headlamps aimed by moving the reflector relative to the lens and headlamp housing, or vice versa, the paragraph requires conformance with respect to the applicable photometrics 'with the lens at any position relative to the reflector within the aim range limits of paragraph S7.7.3 and S7.7.4 or any combination.' This clearly indicates that when a replaceable bulb headlamp that is aimable as provided in S7.7.2.2 is adjusted to the extreme of its range, and at all positions in between, it must continue to meet all applicable photometrics. We interpret this requirement as also applying to headlamp systems of replaceable bulbs subject to S7.7.3 and S7.7.4, but aimable in a manner outside S7.7.2 (such as movement of the entire headlamp, rather than its lens or reflector). I hope that this answers your question. Please note that under recent amendments to Standard No. 108, paragraphs S7.7.2.2, S7.7.3, and S7.7.4 have been renumbered respectively S7.8.2.2, S7.8.3, and S7.8.4. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam5520OpenMr. Mark Warlick Four Winds International Corporation 791 C.R. 15 P.O. Box 1486 Elkhart, IN 46515-1486; Mr. Mark Warlick Four Winds International Corporation 791 C.R. 15 P.O. Box 1486 Elkhart IN 46515-1486; "Dear Mr. Warlick: This responds to your fax asking about the meanin of 'designated seating position' for purposes of the Federal motor vehicle safety standards. You noted that the RVIA Handbook, dated April 23, 1991, states that 'it is the NHTSA's position that, as a minimum, there must be as many designated seating positions as there are sleeping accommodations.' You asked whether this statement is still in effect, and, if so, where you can find it in the Code of Federal Regulations. You also asked what defined area makes up one sleeping position. This will confirm that it continues to be NHTSA's position that, as a minimum, there must be as many designated seating positions as there are sleeping accommodations. This position is based on the definition of 'designated seating position,' which is set forth at 49 CFR 571.3. Under that definition, the question of whether a position in a vehicle constitutes a designated seating position is dependent in part on whether the position 'is likely to be used as a seating position while the vehicle is in motion.' If a manufacturer designs a vehicle to sleep a particular number of persons, e.g., six persons, it is logical to assume that those six persons will ride in the vehicle to their sleeping destination. Therefore, there must be at least six designated seating positions in the vehicle. A more complete discussion of this issue is presented on p. 23234 of the enclosed Federal Register notice (Final rule amending the definition of 'designated seating position,' April 19, 1979). We do not have a definition of what area makes up one sleeping position. NHTSA would consider all available information to determine the number of sleeping positions in a vehicle. This would include the size of the sleeping accommodations, e.g., whether an area is large enough to accommodate more than one person, and advertising by the manufacturer and dealers. I hope this information is helpful. If you have further questions, please feel free to call Edward Glancy of my staff at (202) 366-2992. Sincerely, Philip R. Recht Acting Chief Counsel Enclosure"; |
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ID: aiam0722OpenMr. F. A. Stewart, Vice President Safety & Reliability, American Motors Corporation, 14250 Plymouth Road, Detroit, MI, 48232; Mr. F. A. Stewart Vice President Safety & Reliability American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Stewart: This is in reply to your letter of May 8, 1972, as to which component included in a list attached to your letter are subject to the requirements of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' A related list was left with Mr. Joseph Zemaitis by Mr. Jim Richardson on April 25, 1972, and our letter responds to this list as well. I would point out that, in line with a suggestion you make, consideration is presently being given to an amendment to the standard which could alter our response regarding some of these components.; Paragraph S4. of Standard No. 302 lists the motor vehicle component subject to the standard. The following components you list appear to be among those specifically enumerated in that paragraph and are accordingly subject to the standard: roof bow silencer (headlining), center arm rest cushion and back boards, tape used in seat assembly, (seat cushions, seat backs), and center pillar trim panels (trim panels).; Plastic roof bows to retain hardboard roof trim seem to be closel related to or a different description of headlining and if so, would also be subject to the standard. In addition, 'a roll bar pad assembly' and steering wheel pads would appear to fall within the phrase, '. . . padding . . . designed to absorb energy on contact by occupants in the event of a crash.' Stereo speaker grills and cones incorporated into a door or rear shelf would be considered part of a 'trim panel' and 'compartment shelf,' respectively.; The following components from your list would not be subject to th standard unless they are '. . .any other materials . . . designed to absorb energy on contact by occupants in the event of a crash': fresh-air deflector, instrument panel end cap, pinch welt, control knobs, transfer case shift lever gasket, dome lamp bezel and lens, 'A'. 'B', 'C', and 'D' post covers, instrument cluster lens, heater/air conditioning distribution ducts, defroster nozzle, defroster and air conditioner outlets, assist straps - door or instrument panel mounted, steering wheel rim material, and wood grain overlay adhered to gauge panel.; The following items that you list are not enumerated in S4.1, and a you state they are not energy absorbing, would not be subject to the standard: front face of instrument panel and glove box door, and cover for steering wheel rims. Finally, based on your description of both roof-silencer pads and dash pads, they would not be subject to the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1830OpenMr. David E. Martin, General Motors Corporation, General Motors Technical Center, Warren, MI 48090; Mr. David E. Martin General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Martin: This responds to General Motors' January 14, 1975, request fo confirmation that a Type II seat belt assembly demonstrated to Messrs. Carter, Detrick, Hofferberth, Burgett, Hitchcock, and Herlihy of the NHTSA on December 17, 1974, satisfies the requirements of S7.1.1 of Standard No. 208, *Occupant crash protection*, that the lap belt portion 'adjust by means of an emergency-locking or automatic-locking retractor.' You describe the seat belt assembly as of the single retractor, continuous loop type, with a B-pillar-mounted 'window shade' emergency-locking retractor, and a one-way frictional 'D ring' buckle tongue which limits return of webbing to the lap belt portion from the torso portion when the belt assembly is in use. At the December 17 demonstration you specifically asked if the 'D ring' frictional characteristics satisfy the criterion established in a September 25, 1972, letter to Renault, Inc. (copy enclosed), that 'the friction in the buckle is low enough that the normal motion of the occupant against the shoulder belt cinches up the lap belt.'; Section S7.1.1 requires adjustment of the lap belt portion 'by means o an emergency-locking or automatic-locking retractor' and adjustment in most cases of the upper torso portion 'by means of an emergency-locking retractor.' The language permits some single retractor, continuous loop systems as long as the single retractor does 'automatically adjust' the tension of the lap belt portion to prevent excessive belt slack. Because of the submarining danger of a slack lap belt, the NHTSA has restricted the acceptability of continuous loop systems under S7.1.1 in two areas.; One restriction was set out in the Renault letter and it is the basi for your question whether the GM 'D ring' has a sufficiently low level of friction to qualify the lap portion as 'automatically adjustable.'; We would like to clarify that letter by emphasizing that, to conform t the requirements, the assembly must be *designed* by the manufacturer with a sufficiently low level of friction to qualify the lap portion as 'automatically adjustable.' Thus it is the manufacturer who determines whether or not the particular belt is designed to satisfy the requirements of the standard. In your December 17 demonstration we saw no evidence of design deficiency in limited use of that continuous loop system.; The other restriction was set out in a March 9, 1973, letter to Genera Motors (copy enclosed). It limits the use of 'comfort clips' on the upper torso portion of continuous loop systems. The letter distinguishes continuous loop systems from systems that have separate lap and shoulder belt retractors. It concludes that 'a comfort clip would be acceptable under S7.1.1 of the standard, so long as the shoulder belt is otherwise capable of adjustment as required by S7.1.1.'; This restriction has since been the subject of an NHTSA proposa (Docket 74-32, Notice 1) which would restrict the use of 'a device used to limit retractive action of an emergency-locking retractor for the comfort of the occupant' to seat belt assemblies that have 'an individually adjustable lap belt.' General Motors' response to that proposal and its anticipated use of a 'window shade' device in future continuous loop systems assume that NHTSA intends to permit 'belt tension relief' devices on all continuous loop systems. I would like to point out that this issue is outstanding in Docket 74- 32.; Pursuant to your request for confidential treatment of this question o a new seat belt assembly, this letter will be made public only after the introduction of the new vehicle in question.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam0688OpenMr. Lee S. Richards, Lee Equipment, Incorporated, 38 Old Route 6, Carmel, NY 10512; Mr. Lee S. Richards Lee Equipment Incorporated 38 Old Route 6 Carmel NY 10512; Dear Mr. Richards: This is in reply to your letter of April 11, 1972, to our New Yor office, that has been referred to me.; Paragraph 568.3 of Title 49 of the Code of Federal Regulations states ''Final stage' manufacturer means a person who performs such manufacturing operations on an incomplete vehicle that it becomes a completed vehicle.'; The subject is also dealt with in the Preamble to Part 568 '. . .Th definitions by which the regulation establishes the categories of 'incompete (sic) vehicle,' 'completed vehicle,' and the three categories of vehicle manufactures provide a framework within which each *may categorize himself* and his products. Of necessity, the definitions are broad and may not clearly define individual situations . . . . In the usual case, it will be possible for the affected manufacturers to *reach agreement between themselves* as to their respective obligations . . . .' (emphasis added); In the event that the matter is in dispute between yourself and th tank installer we would be inclined, based on the information in hand, to rule that the tank installer is the final stage manufacturer inasmuch as the equipment that you install would be 'readily attachable.'; Your obligations as a manufacturer would be the same whether the tan you install on the new chassis is new or used.; I trust this will answer your questions. Sincerely, Francis Armstrong, Director, Office of Standard Enforcement, Motor Vehicle Programs; |
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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.