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: aiam2754OpenMr. B. Henderson, Legislative Engineer, NVT Motorcycles Limited, Lynn Lane, Shenstone, Lichfield, Staffordshire WS14 OEA, England; Mr. B. Henderson Legislative Engineer NVT Motorcycles Limited Lynn Lane Shenstone Lichfield Staffordshire WS14 OEA England; Dear Mr. Henderson: This is in reply to your letter of December 15, 1977, asking for a interpretation of S5.1 of Federal Motor Vehicle Safety Standard No. 123, *Motorcycle Controls and Displays*. You have asked whether a switch on the right handlebar of moped exported by NVT to the United States may be viewed as the 'supplement engine stop control' that the standard requires.; You have noted that the switch is 'identified as required in Table 3 and that the engine can be stopped by the clutch that is part of the starter arrangement. To answer your question it is necessary to make several assumptions as your letter is not complete enough to allow a definitive response. If the normal or recommended method of stopping the vehicle is through the clutch then the switch may serve as the supplemental engine stop control. If, however, turning the switch to off is the normal or recommended method of stopping the vehicle, it cannot be viewed as a supplemental control.; We assume that the switch is identified as 'engine stop' and no 'ignition' since you refer to it as a means of stopping the vehicle and imply that the clutch arrangement is the only method of starting it. If our assumptions are not correct, please inform us of the correct facts so that we may advise you accordingly.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3515OpenMr. James S. Nasby, Director of Engineering, Pathfinder Auto Lamp Company, 6201 W. Howard Street, Niles, IL 60648; Mr. James S. Nasby Director of Engineering Pathfinder Auto Lamp Company 6201 W. Howard Street Niles IL 60648; Dear Mr. Nasby: This responds to your November 25, 1981, letter to Roger Tilton of thi Office regarding the applicability of vehicle identification number (VIN) requirements to trailer kits manufactured by your company.; It is our view that these trailer kits must comply with the VI requirements of FMVSS 115. Your kits contain all components necessary to assembly a complete trailer, and are advertised as capable of being readily assembled with simple tools such as screwdrivers and wrenches. We see no relevant basis for distinguishing between such kits and completed trailers for purposes of determining the applicability of FMVSS 115.; While the VIN requirements do provide anti-theft benefits, they als are important to this agency in administering the defect recall program as well as to State motor vehicle departments and insurance companies. Further, even if this agency exempted trailer kits from VIN requirements, purchasers of your kits would likely face difficulties when they attempt to register their trailers with the States. We expect most states to soon begin checking VIN's as part of the vehicle registration process, and vehicles without a VIN or with a nonconforming identification number might face rejection by the state motor vehicle departments notwithstanding a technical exemption from NHTSA. We feel that in the long run, the best and simplest solution is for vehicle manufacturers to assign a VIN which meets the requirements of FMVSS 115.; Should you still wish to seek an exemption from the standard procedures for obtaining exemptions are set forth in Title 49 of the Code of Federal Regulations, Part 555, a copy of which is enclosed. Such exemptions are available for not more than three years.; You should also be aware that certification labels must contain bot the month and year of a vehicle's manufacture. See 49 CFR 567.5(b)(5). The copy of the label you sent us contains only the year of manufacture.; If you have further questions on this matter, feel free to contact u again.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1528OpenMr. J.M. Craig, President, Gator Trailer Corp., 1925 E. Beaver, Jacksonville, FL, 32206; Mr. J.M. Craig President Gator Trailer Corp. 1925 E. Beaver Jacksonville FL 32206; Dear Mr. Craig: This is in reply to your letter of May 30, 1974, describing you pontoon boat trailer and asking if it is permissible to offer a '. . . clamp on light bar at the rear along with front side marker amber lighting for installation forward on the pontoon boat itself?' As you point out 'This would mean that the user would have to install the lighting each time a rig is put on the highway.'; Your proposed installation arrangement does not appear to be i conformance with paragraph S4.3.1 of Federal Motor Vehicle Safety Standard No. 108, which requires that lighting and reflective devices be *securely* mounted on a rigid part of the *vehicle*. If the cargo partially obscures the visibility of the required lighting devices on the trailer, State regulations would govern any additional, temporarily attached lighting devices on the cargo.; We trust this answers your question. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1482OpenMr. Rick Shue, Product Safety Engineer, Volvo of America Corporation, Product Engineering and Development, Rockleigh, NJ 07647; Mr. Rick Shue Product Safety Engineer Volvo of America Corporation Product Engineering and Development Rockleigh NJ 07647; Dear Mr. Shue: This is in response to your letter of April 16, 1974, requesting a interpretation of the test procedure specified in Standard No. 301 (Docket 73-20, Notice 2) concerning the operation of the vehicle's fuel pump during testing.; Paragraph S7.1.3 of the standard requires that electrically driven fue pumps be in operation during the barrier crash tests if they normally operate with the activation of the vehicle's electrical system. If the pump is incapable of functioning with the independent activation of the electrical system and requires the operation of the vehicle's engine, then the pump should not be running during the barrier crash tests.; Once the barrier crash tests have been completed, if the fuel pump wa operating it may be deactivated, as the standard only requires that it operate during the crashes.; Thank you for your inquiry. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3145OpenMr. William E. Barry, Chief, Cleveland Fire Department, 1645 Superior Avenue, Cleveland, OH 44114; Mr. William E. Barry Chief Cleveland Fire Department 1645 Superior Avenue Cleveland OH 44114; Dear Mr. Barry: This is in response to your letter of July 2, 1979, in which you aske for copies of any current or recommended standards concerning the use of plastic auxiliary fuel tanks. May I apologize for the delay in this response.; I have enclosed a copy of a letter, which was sent to a company whic planned to manufacture auxiliary fuel tanks and to do some installation, that details the ways in which the safety standards and statutes administered by this agency apply to the manufacture of auxiliary fuel tanks of all types. In addition, I have enclosed a copy of an advance notice of proposed rulemaking that this agency issued with respect to a proposal to issue performance standards applicable to nonmetallic fuel tanks.; At this time the agency does not have any standards applicable to th use of auxiliary fuel tanks. However, several months ago we issued a consumer advisory warning against carrying fuel in portable containers in the trunks of cars. We consider this advisory applicable not only to portable containers but to any fuel container mounted in an area not normally consigned to such use. I have enclosed a copy of this advisory for your information. In addition, we are planning to issue a press release in the near future specifically addressed to the dangers of using auxiliary fuel tanks.; If you have any reports, case histories, photographs, or other materia concerning any fires or fire problems caused by the use of auxiliary fuel tanks we would be most grateful if you would allow us to examine them. Your concern in this area of vehicle safety is deeply appreciated.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4680OpenMr. Scott K. Hiler Manager, R & D Lab The C.E. White Co. 417 N. Kibler Street New Washington, OH 44854; Mr. Scott K. Hiler Manager R & D Lab The C.E. White Co. 417 N. Kibler Street New Washington OH 44854; "Dear Mr. Hiler: This responds to your letter seeking an interpretatio of Standard No. 210, Seat Belt Assembly Anchorages (49 CFR /571.210). Specifically, you asked if the strength test set forth in that standard requires simultaneous testing of all the safety belt anchorages for a passenger seat in school buses with a gross vehicle weight rating (GVWR) of 10,000 pounds or less, when those anchorages are installed on the seat frame, or whether those anchorages can be tested individually. The answer is that such anchorages are tested individually under the current provisions of the strength test in Standard No. 210. Standard No. 222, School Bus Passenger Seating and Crash Protection (49 CFR /571.222) establishes the occupant protection requirements for passenger seating positions in school buses. Section S5(b) of Standard No. 222 provides that school buses with a GVWR of 10,000 pounds or less shall meet the requirements of Standard No. 210, among other standards. Section S4.2 of Standard No. 210 sets forth the strength test for anchorages. Section S4.2.4 reads as follows: 'Except for common seat belt anchorages for forward-facing and rearward-facing seats, floor-mounted seat belt anchorages for adjacent designated seating positions shall be tested by simultaneously loading the seat belt assemblies attached to those anchorages.' Note that the only anchorages subject to a simultaneous testing requirement are floor-mounted anchorages. The anchorages described in your letter and shown in the photographs enclosed with that letter are mounted on the seat frame. Therefore, those anchorages would not be tested simultaneously to determine compliance with Standard No. 210. I should also point out that NHTSA has proposed to amend section S4.2.4 of Standard No. 210 so that all seat and floor-mounted anchorages common to one seat would be tested simultaneously during the strength test. Ihave enclosed a copy of that proposal for your information. The interpretation in this letter may no longer be correct after the effective date of any final rule adopting that proposal. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure"; |
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ID: aiam1178OpenMr. Donald W. Taylor, Engineering Liaison Representative, Volvo of America Corporation, Rockleigh, NJ 07647; Mr. Donald W. Taylor Engineering Liaison Representative Volvo of America Corporation Rockleigh NJ 07647; Dear Mr. Taylor: This is in reply to your letter of July 11, 1973, asking for a waive of 49 CFR S575.6(c) with respect to consumer information that Volvo of America would like to supply to prospective purchasers of 500 passenger cars beginning July 30, 1973.; There is no provision in the Consumer Information Regulation empowering the Administrator to waive the 30 day requirement and therefore we are unable to grant this request. We do not view the lack of this authority as unjust, given the purpose of the requirement 'so that there may be an evaluation and dissemination to the public of this information if deemed appropriate' (34F.R.11501).; We received your material on July 12, and the 30 day period will expir on August 11.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam5642OpenMr. A.D. Fisher 308 Lolly Lane Jacksonville, FL 32259; Mr. A.D. Fisher 308 Lolly Lane Jacksonville FL 32259; Dear Mr. Fisher: This is in reply to your letter of October 11, 1995 asking for our comments on the relationship of your lighting invention, 'The Enlightener,' to Federal Motor Vehicle Safety Standard (FMVSS) No. 108. The Enlightener is intended to replace the center highmounted stop lamp. The lens has two colors, divided between amber at the top and red at the bottom. The amber portion is lit in a steady burning mode when both the accelerator and brake are not depressed, and in a flashing mode when the transmission lever is in Reverse. The red portion is lit when the brake pedal is depressed and amber is extinguished. This device would not be permissible under FMVSS No. 108. The center highmounted stop lamp must stand alone, the lamp cannot serve another function, and paragraph S5.4(a) prohibits combining it with any other lamp. In addition, the backup function on motor vehicles is furnished by a steady burning white lamp, required by FMVSS No. 108. The presence of a flashing amber lamp operating simultaneously would impair the effectiveness of the backup lamp by sending a conflicting signal. I am sorry that we cannot provide you a more positive response. If you have any questions, you may refer them to Taylor Vinson of this office by calling (202) 366-5263. Sincerely, Samuel J. Dubbin Chief Counsel; |
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ID: aiam2187OpenMr. J. A. Hogan, Gibson, Darden and Hotchkiss, 912 City National Building, Wichita Falls, TX 76301; Mr. J. A. Hogan Gibson Darden and Hotchkiss 912 City National Building Wichita Falls TX 76301; Dear Mr. Hogan: As you requested in your letter of December 30, 1975, I am forwardin to you a copy of the odometer disclosure regulation (49 CFR Part 580) promulgated pursuant to section 408 of the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513).; The regulation does not require that disclosure documents be retained Thus, any individual who maintains a copy of an odometer disclosure statement, does so of his own accord. There is nothing in the odometer law or regulation that would prevent a person from making disclosure statements available to interested parties. However, neither does the law demand that such documents be made public.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam4950OpenMr. Michael A. Martin Program Manager Bureau of Highway Safety State House Station 42 Augusta, Maine 04333; Mr. Michael A. Martin Program Manager Bureau of Highway Safety State House Station 42 Augusta Maine 04333; "Dear Mr. Martin: This is in regard to your letter of December 9, 1991 regarding school buses. Your three questions are addressed below. 1. (W)hat is the general rule to which states need to comply with regarding Federal school bus safety standards? What bus safety modifications would not be restricted by 15 U.S.C. 1392(d)? Section 103(d) of the National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1392(d)) provides that: Whenever a Federal motor vehicle safety standard ... is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard. Nothing in this section shall be construed to prevent ... any State or political subdivision thereof from establishing a safety requirement applicable to motor vehicles or motor vehicle equipment procured for its own use if such requirement imposes a higher standard than that required to comply with the otherwise applicable Federal standard. Section 103(d) preempts state requirements for school buses covering the same aspect of performance as an applicable Federal motor vehicle safety standard (FMVSS) that are different from the applicable FMVSS except to the extent that the requirements impose a higher level of performance and apply only to vehicles procured for the State's use. A state law imposing higher requirement would be preempted under 103(d) to the extent that the law requires all school buses manufactured for use in the state to comply with the law. The law would not be preempted to the extent that it applies to public school buses. The agency has previously interpreted the phrase 'vehicles procured for (the State's) own use' to include public school buses and school buses operated and owned by a private contractor under contract to transport children to and from public school. See, for example, February 20, 1987 letter to Mr. Martin Chauvin (copy enclosed). 2. Would Federal safety standards restrict a state from requiring safety belts on school buses? A state requirement that all school buses be equipped with safety belts regulates the same aspect of performance as the Federal standard for school bus occupant crash protection (FMVSS No. 222, School Bus Passenger Seating and Crash Protection) and would not be identical to that standard for large school buses (those with a gross vehicle weight rating (GVWR) over 10,000 pounds). FMVSS No. 222 requires school buses to provide passenger crash protection through a concept called 'compartmentalization.' Providing compartmentalization entails improving the interior of the school bus with protective seat backs, additional seat padding, and better seat spacing and performance. These interiors are intended to keep occupants in their seating area and protect them during a crash. FMVSS No. 222 requires the additional protection of safety belts at each passenger position in small school buses (10,000 pounds or less GVWR) because these buses experience greater force levels in a crash. A state requirement for safety belts on school buses would be identical to the level of performance required for small school buses, but would specify a different level of performance for large school buses. However, because the state requirement specifies a higher level of performance for large school buses than that required by FMVSS No. 222, Maine may require the installation of safety belts in school buses procured by the State or its political subdivisions, as long as the Federal requirements for compartmentalization are not compromised. 3. Could a school bus fleet modify the rear lighting configuration of their buses (8 light system) to reduce the potential for other vehicles rear-ending buses during poor visibility conditions, e.g., fog? ... The proposed change is to replace the white 8 inch back-up lights with 8 inch red sealed beam warning lights similar to the two at the upper level of the rear end of the bus. These would flash in an alternating criss-cross fashion when the bus is stopped loading or discharging students. The small white lights at the lowest level of the rear end of the bus would each be replaced with white, universal backup lights angled to also direct their beams at 45 degree angles out from the rear of the bus. The answer to your question is yes if the school district or its fleet contractor performs the modification itself. The National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1381 et seq.) authorizes this agency to issue FMVSS applicable to new motor vehicles and new items of motor vehicle equipment. Section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) prohibits the sale for purposes other than resale of any new motor vehice or item of motor vehicle equipment unless it is in conformity with all applicable FMVSSs. After the first purchase of a vehicle in good faith for purposes other than resale, the only provision in Federal law that affects a vehicle's continuing compliance with an applicable safety standard is set forth in Section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section provides that: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard. This provision does not regulate in any manner how a vehicle owner can modify his or her vehicle. I note, however, that this agency encourages vehicle owners not to tamper with their vehicle's safety equipment if the modification would degrade the safety of the vehicle. In addition, it is possible that the modifications you describe could be made by one of the named commercial entities without violating the 'render inoperative' provision. The modification you describe affects two requirements of FMVSS No. 108, Lamps, reflective devices, and associated equipment. FMVSS No. 108 requires buses, including school buses, to have at least one backup light meeting the photometric and height requirements of SAE Standard J593c, February 1968. If the small white lights at the lowest level of the rear end of the bus comply with these requirements, the vehicle would continue to conform with this requirement. Section S5.1.4 of FMVSS No. 108 requires school buses to have a system of either four red or four red and four amber signal lamps which conform to SAE Standard J887, July, 1964. The modification you describe would add an additional two red signal lamps to the existing eight light system. Section S5.1.3 of FMVSS No. 108 states that '(n)o additional lamp, reflective device or other motor vehicle equipment shall be installed that impairs the effectiveness of lighting equipment required by this standard.' It is our opinion that the addition of two red signal lamps would not violate this provision. I hope this information is helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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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.