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: nht91-7.3OpenDATE: November 7, 1991 FROM: Takashi Odaira -- Chief Representative, Emission & Safety, Isuzu TO: P. J. Rice -- Chief Counsel, NHTSA COPYEE: Mr. Sakai; Mr. Watanabe TITLE: Test Conditions - Side Impact (FMVSS 214) ATTACHMT: Attached to letter dated 1/14/92 from Paul Jackson Rice to Takashi Odaira (A39; Std. 214) TEXT: The purpose of this letter is to seek your agency's interpretation about the test conditions specified in FMVSS 214, Side Impact Protection. S3. (b), (c) and (d) of FMVSS 214 specify passenger cars whose rear seating areas are so small that the rear seat requirements do not apply. However, when such passenger cars are subjected to dynamic side impact test, is it necessary to place a test dummy on their rear seating positions? I would appreciate receiving your quick response to this question. |
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ID: nht91-7.30OpenDATE: December 4, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Darrell E. Lischynski -- P.Eng., Project Manager, Energy and Processing, Prairie Agricultural Machinery Institute TITLE: None ATTACHMT: Attached to letter dated 10-3-91 from Darrell E. Lischynski to Mary Versailles (OCC 6562) TEXT: This responds to your letter of October 3, 1991 concerning Calmar Industries' Seat Lift Kit for Ford Supercab trucks. As described by you, the "Seat Lift Kit is an attachment to raise the rear bench seat in Ford Supercab trucks. The kit does not alter the factory seat, and uses the factory seat belts. However, the seat mounts are changed, and an extension is provided to raise the seat belt attachment point." You asked which safety standards this kit must meet. The National Highway Traffic Safety Administration has issued one safety standard that applies to seats, Standard No. 207 Seating Systems, and the following safety standards that apply to; safety belts: Standard No. 208, Occupant Crash Protection, Standard No. 209, Seat Belt Assemblies, and Standard No. 210, Seat Belt Assembly Anchorages. All safety belts sold in the United States must be certified as complying with Standard No. 209, regardless of whether the belts are installed as original equipment in a motor vehicle or sold as a replacement part. However, since you indicate that the kit uses the factory-installed safety belts, it does not appear that you need to be concerned with this standard. Since Standard No. 207, Standard No. 208 and Standard No. 210 apply only to new vehicles, they are called vehicle standards. The National Traffic and Motor Vehicle Safety Act specifies that vehicles must conform with all applicable safety standards up until the first purchase for purposes other than resale. Therefore, if the seat lift kit is installed in a truck before its sale to its first purchaser, the vehicle with the lift kit installed must conform to these standards. After the first purchase, the vehicle is no longer required by Federal law to conform with all safety standards. However, section 108(a)(2)(A) of the Safety Act provides as follows: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard . . . . In order to avoid violating this provision, a manufacturer, dealer, distributor, or repair business which installed the lift kit would need to ensure, by carefully comparing the lift kit and its planned installation with the requirements of relevant safety standards, that such installation enables the vehicle to continue to comply with all applicable safety standards. Violations of S108(a)(2)(A) are punishable by civil fines of up to $1,000 per violation. I note that section 108(a)(2)(A) does not affect modifications made by vehicle owners to their own vehicles. I hope you find this information helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. |
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ID: nht91-7.31OpenDATE: December 5, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA; (Signature by Steve Wood) TO: Gene Byrd -- Legris Incorporated TITLE: None ATTACHMT: Attached to letter dated 9-23-91 from Gene Byrd to Vernon Bloom (OCC 6551) TEXT: This responds to your September 23, 1991 letter asking about the air pressure requirement specified in S7.3.8 of Standard 106, Brake Hoses. Your letter has been referred to my office for reply. Paragraph S7.3.8 states that an air brake hose assembly shall contain air pressure of 200 psi for 5 minutes without loss of more than 5 psi. You ask whether Standard 106 specifies the length of the hose for an assembly tested to S7.3.8. The answer is no; the standard does not have a generic specification for hose length. Instead, each brake hose assembly is required to meet this requirement as manufactured and sold. For purposes of compliance testing, NHTSA obtains a brake hose assembly specimen by purchasing it on the market or directly from the manufacturer. The length of the hose might vary from assembly to assembly, depending on the particular configuration of an assembly. The assembly is tested as sold to obtain performance results that indicate the assembly's real world performance. While S7.3.8 is a performance requirement for assemblies, we understand that your company (an end fitting manufacturer) seeks to ensure that an assembly made with your fitting will not fail to meet S7.3.8 due to the fitting. Since an assembly is tested to S7.3.8 in the configuration in which it is sold, you could test to the requirement using the length of hose that will be used with your fitting. Legris might be able to avoid duplicative tests by conducting "worst case" testing, such as tests using a fitting with a hose of a length most likely to exhibit an excessive loss of air pressure. Please contact us if you have further questions. |
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ID: nht91-7.32OpenDATE: December 5, 1991 FROM: John H. Heinrich -- District Director, U.S. Customs Service, Department of Treasury; Kathleen M. Tobin -- Acting Director, Fines, Penalties & Forfeitures, U.S. Customs Service, DOT; Signature illegible TO: Office of Chief Counsel, DOT TITLE: None ATTACHMT: Attached to letter dated 1/9/92 from Paul Jackson Rice to John H. Heinrich (A39; Std. 211) TEXT: Enclosed find a petition for relief from the forfeiture of 200 Spinner Wheel Nuts seized by this service on October 8, 1991 as violative of Title 49, Code of Federal Regulations, Part 571.211. While thememorandum of November 13, 1991 from the importer to his broker and the broker's November 18, 1991 petition stress safety considerations and the need to "replace" worn parts, the importer's own parts list (page 26) refers to: "....conversion kits...designed to CONVERT your disc wheeled TD or TF to wire wheels...These kits enhance the appearance of any TD and are identical to the original factory OPTION for the TF" (underlines added). The petitioner expresses the opinion that these "imported spinners" should be exempt from any general DOT safety regulation. Please provide us with your recommendation within 30 days. |
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ID: nht91-7.33OpenDATE: December 5,1991 FROM: Harvey D. Benson -- Chief Engineer, Landoll Corporation TO: Richard Carter -- Office of Vehicle Safety Standards, NHTSA TITLE: None ATTACHMT: Attached to letter dated 2/3/92 from Paul Jackson Rice to Harvey D. Benson (A39; Std. 121) TEXT: I need answers for two questions: 1. Is a HEAVY HAULER TRAILER required to have spring brades? We manufacture tandem and triple axle trailers with capacities up to 12O,OOO GVWR which have load carrying decks less than 40 inches above the ground. Our understanding of 49 CFR Ch V, 571.121 is that spring brakes are not required but there may be other regulations which apply. I have had customers call stating that they were ticketed for not having spring brakes. I need a definitive statement referencing specific regulations to answer this question. 2. What are the requirements for bulkhead (cab protection) on truck chassis beds? We manufacture slide back beds mounted on single and tandem axle truck chassis. I have not been able to find requirements as to size and impact capacity for cab protecting bulkheads. |
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ID: nht91-7.34OpenDATE: December 6, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Michael E. Kastner -- Director of Government Relations, National Truck Equipment Association TITLE: None ATTACHMT: Attached to letter dated 9-4-91 from Michael E. Kastner to Paul J. Rice (OCC 6447) TEXT: This responds to your letter of September 4, 1991, asking whether an altered vehicle label must be added under the following circumstances. An NTEA member receives a truck which is certified as a completed vehicle. This vehicle has not yet been titled or registered for use in any state. The NTEA member then installs a piece of equipment. This piece of equipment would not be considered readily attachable, nor would this equipment modify the completed vehicle's weight ratings. Both the completed truck manufacturer and the equipment manufacturer have stated that installation of this equipment would not affect compliance with any federal motor vehicle safety standard. If the modification you describe is performed prior to the first purchase in good faith of the vehicle for purposes other than resale, the answer to your question is yes. A person is considered an alterer if (1) they alter the vehicle in any manner "other than by the addition, substitution, or removal of readily attachable components ... or minor finishing operations," or (2) they alter "the vehicle is such a manner that its stated weight ratings are no longer valid." Since the conditions you describe involve equipment which is not readily attachable, the NTEA member would be considered an alterer. If considered an alterer, the NTEA member would be subject to the certification requirements of 49 CFR S567.7. These requirements include provisions that the alterer supplement the existing manufacturer certification label, which must remain on the vehicle, by affixing an additional label. The label must state that the vehicle as altered conforms to all applicable Federal motor vehicle safety standards. The label would also state the alterer and the month and the year in which the alterations were completed. If the modification you describe is performed after the first purchase in good faith of the vehicle for purposes other than resale, the NTEA member would not be considered an alterer and an alteration label would not have to be attached. Under these conditions, the only provision in Federal law that affects the vehicle's continuing compliance with applicable safety standards is set forth in section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section provides: 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.
In general, this "render inoperative" provision would require any of these named entities to ensure that any additional equipment installed in a vehicle would not negatively affect the compliance of any component or design on the vehicle with applicable safety standards. Violations of S108(a)(2)(A) are punishable by civil fines up to $1,000 per violation. I hope this information is helpful. If you have further questions, please contact Mary Versailles of my staff at this address or my telephone at (202) 366-2992. |
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ID: nht91-7.35OpenDATE: December 6, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Floyd J. Barkman -- Vice President Sales & Marketing, Collins Bus Corporation TITLE: None ATTACHMT: Attached to letter dated 10-16-91 from Floyd J. Barkman to Susan Schruth (OCC 6589) TEXT: This responds to your letter of October 16, 1991, to Ms. Susan Schruth of the Urban Mass Transportation Administration. Because your questions concern a final rule issued by the National Highway Traffic Safety Administration (NHTSA), Ms. Schruth has referred your letter to our office for response. Your questions are as follows. 1. Based on a final ruling that went into effect September 1, 1991, all MPV and/or buses with a gross vehicle weight less than 10,000 pounds are required to have Type 1 or Type 2 occupant restraints at all seated positions. Also, all outboard occupants or passengers are required to have three point shoulder harness. We also understand school buses are exempt from the outboard shoulder harness. Are these statements correct and are there any exceptions to these rulings? Your understanding of the September 1, 1991, final rule is correct. The only exception to these requirements is that the rear-seat lap/shoulder belt requirement does not apply to rear outboard seating positions located adjacent to a walkway located between the seat and the side of the vehicle to allow access to more rearward seating positions. I am enclosing a copy of the Federal Register notice for this final rule. A discussion of this exception is found on page 46258. A discussion of the agency's rationale for excluding small school buses from the rear-seat lap/shoulder belt requirement is found on page 46260 of the same notice. 2. We build under 10,000 GVW buses for the day care industry that use school bus interiors with school bus safety seats and lap belts at all locations. The exterior of the bus is commercial. Would these buses require the outboard shoulder harness? The answer to this question depends on whether these vehicles are classified as school buses. Under NHTSA's certification requirements (49 CFR Part 567), a vehicle's type is determined using the definitions set out in 49 CFR S571.3. A school bus is defined as a motor vehicle designed for carrying 11 or more persons, including a driver, to and from school or school-related events. A program for pre-primary age children is considered a school if the program is primarily educational rather than custodial in nature. If your vehicle is a not a school bus, it must comply with the rear-seat lap/shoulder belt requirement. If the vehicle is a school bus, it does not have to comply with this requirement. 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.
Attached to Federal Register 49 CFR Part 571 pages 46257 - 46268 (text omitted) |
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ID: nht91-7.36OpenDATE: December 9, 1991 FROM: Michael A. Martin -- Program Manager, Bureau of Highway Safety, State House Station 42, Augusta, Maine TO: Mary Versailles -- Office of Chief Counsel, NHTSA TITLE: None ATTACHMT: Attached to letter dated 2/14/92 from Paul Jackson Rice to Michael A. Martin (A39; VSA 103(d); Std. 108; Std. 222); Also attached to letter from Erika Z. Jones to Martin V. Chauvin TEXT: In follow-up to our telephone conversation of November 20 concerning federal school bus safety standards and a state's ability to make improvements beyond those standards would you please provide a written response to the following. First, what 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)? Would federal school bus safety standards restrict a state from requiring safety belts on school buses? Could a school bus fleet modify the rear lighting configuration on their buses (8 light system) to reduce the potential for other vehicles rear-ending buses during poor visibility conditions e.g., fog? Please refer to the attached diagram. 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. This would greatly improve the driver's ability to see when backing the bus in a direction both behind and to the side of the bus. I would appreciate your interpretation of what safety modifications a state may propose that would definitely be preempted by federal school bus safety standards. Thank you for your assistance.
Attachments Drawing entitled Rear End of School Bus, Current System. Drawing entitled Rear End of School Bus, Proposed System. (Drawings omitted) |
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ID: nht91-7.37OpenDATE: December 9, 1991 FROM: Hanno Westermann -- Hella KG Hueck & Co.; Olaf Schmidt -- Hella KG Hueck & Co. TO: Richard L. van Iderstine -- NHTSA TITLE: Definition of 2 or 4 Headlamp System ATTACHMT: Attached to letter dated 3/5/92 from Paul Jackson Rice to Herrn. Westermann u. Schmidt (A39; Std. 108) TEXT: Since the great revision of FMVSS No. 108 by Docket 85-15, Notice 12 of February 8, 1990, we are missing a paragraph clarifying the definition of a 2 or 4 headlamp system respectively. In the former version of 108, this definition was done under para. S4.1.1.36, but today there only remains figure 26, which explains the application of photometric requirements with respect to the bulb or bulb combination used. We assume that no changes to the sense of 108 have been made for this matter so that our remarks could be added to FMVSS 108 by short term to avoid the current discrepancies between headlamp manufacturers and the test laboratories. Attached you will find a sketch representing our understanding of the definition of a 2 or 4 lamp system, deriving from the former 108. Many thanks for your endeavours in this and A Merry Christmas and a Happy New Year.
Attachment Drawings of Replaceable Bulb Headlamp Systems. (Graphics omitted) |
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ID: nht91-7.38OpenDATE: December 10, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA (Signature by Kenneth A. Weinstein) TO: James E. Scapellato -- Director, Office of Motor Carrier Standards, FHWA TITLE: Re Standard No. 108 (Heavy duty trailers) Lamps and Reflectors TEXT: This responds to your memorandum of November 20, 1991, asking whether Federal Motor Vehicle Safety Standard No. 108 permits a trailer manufacturer "to equip a heavy-duty flatbed trailer with amber tail lamps in combination with its rear turn signal lamps." Such a combination lamp would be adjacent to combination red stop and taillamps. Standard No. 108 does not directly answer this question. Table II of the standard requires the trailer to be equipped with a pair of red taillamps. Section S5.1.3 of Standard No. 108 prohibits the installation of supplementary lighting equipment "that impairs the effectiveness of lighting equipment required by this standard." Thus, the question is whether the installation of amber taillamps would impair the effectiveness of the trailer's amber turn signal lamps, red stop lamps, and red taillamps. Although the determination of impairment is initially that of the vehicle's manufacturer in certifying compliance of the vehicle to all applicable Federal motor vehicle safety standards, NHTSA may review that determination, and, if clearly erroneous, inform the manufacturer of its views. In this instance, NHTSA believes there is a substantial possibility of impairment of the effectiveness of other rear lamps. When combined with an amber turn signal lamp, the intensity of an amber taillamp might mask the turn signal in operation. Because motorists are not used to seeing steady burning amber lamps on the rear of vehicles, amber taillamps could lead to momentary confusion of a driver following the trailer when the stop lamps are activated, thereby impairing the effectiveness of the stop signal. The presence of simultaneously burning amber and red taillamps could also create some confusion of a following driver approaching the trailer from around a corner to its rear. Thus, we have concluded that a combination amber turn signal and taillamp is implicitly prohibited by Standard No. 108. |
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.