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: aiam3520OpenH. A. Kendall, Ph.D., Executive Secretary, United Sidecar Association, Inc., 1621 Palomino Lane, Kingwood, TX 77339; H. A. Kendall Ph.D. Executive Secretary United Sidecar Association Inc. 1621 Palomino Lane Kingwood TX 77339; Dear Dr. Kendall: This is in reply to your letter of September 9, 1981, asking severa questions about Federal Motor Vehicle Safety Standard No. 108.; You have asked for a clarification of our position on pulsatin headlamps and stoplamps, commenting that several States have expressed a concern 'that a light of variable intensity may be confused by the citizen as an emergency vehicle which is allowed to have flashing headlights.'; As you have indicated, paragraph S4.6(a) of Standard No. 108 require turn signal lamps, hazard warning signal lamps, and school bus warning lamps to flash when activated, while S4.6(b) requires all other lamps to be steady burning. By 'steady burning,' the standard means a light that is essentially unvarying in intensity. There is, however, an exception in S4.6(b) to the 'steady burning' requirement. Means may be provided 'to flash headlamps and side marker lamps for signalling purposes.' Paragraph S3 of the standard defines 'flash' as meaning 'a cycle of activation and deactivation of a lamp by automatic means....' In our view, a lamp whose intensity varies from a higher output to a lower output would not be 'steady burning' or 'flash' within the meaning of those terms and hence would be prohibited. But if complete deactivation occurs, then the lamp 'flashes.' Installation of flashing lamps under the S4.6(b) exception is not restricted to emergency vehicles. It is permissible under the standard for a motorcycle to have a device which gives the motorcyclist the option of causing a motorcycle headlamp to operate automatically through cycles of activation and deactivation instead of burning steadily.; On the other hand, stop lamps that either flash or are of variabl intensity are not allowed by S4.6(b) of Standard No. 108 since they are not steady-burning while in use.; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4031OpenRichard Pertz, Esq., Julian & Pertz, P.C., 1629 Oneida Street, Utica, NY 13501; Richard Pertz Esq. Julian & Pertz P.C. 1629 Oneida Street Utica NY 13501; Dear Mr. Pertz: I regret the delay in replying to your letter of July 12, 1985 regarding interpretations of Standard No. 111, *Rearview Mirrors*. You asked whether the agency has issued any interpretations concerning S5.1.2 of the standard. In addition, you asked whether Ford Motor Company had submitted to the National Highway Traffic Safety Administration (NHTSA) any interpretations of paragraph S5.1.2 of Standard No. 111, regarding requirements for mounting inside rearview mirrors in passenger cars.; This agency administers the National Traffic and Motor Vehicle Safet Act of 1966. As part of its responsibilities, this office issues interpretations of safety standards, upon written request. This agency has issued two interpretations of S5.1.2 of Standard No. 111. Copies of these interpretations are enclosed.; In addition, NHTSA's Office of Vehicle Safety Compliance investigate the compliance of different makes of passenger cars with Standard No. 111 between 1977 and 1981. The Ford passenger car models tested were the Ford LTD, Econoline, and Fiesta and the Mercury Zephyr and Cougar. As part of its submission to the agency in these investigations, Ford provided information on its compliance with S5.1.2. The files are available on microfiche from the Technical Reference Office, Room 5108 (202-426-2768) at the address shown above, and the file numbers are CIR Nos. 1708, 2062, 2063, 2064, and 2245.; Your request in your letter of September 3, 1985, for comments by For on notices of proposed rulemaking on Standard No. 111 has been referred to the Docket Section. They will reply directly to you regarding this information.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1233OpenMr. Louis May, President, Sate-lite Mfg. Company, 6545 W. Irving Park Road, Chicago, Illinois 60634; Mr. Louis May President Sate-lite Mfg. Company 6545 W. Irving Park Road Chicago Illinois 60634; Dear Mr. May: This is in response to your petition of July 26, 1973, to modify th water immersion requirements of Standard 125, *Warning devices*, and the grounds that the test is more severe than typical weather conditions. The standard requires immersion of the device for 2 hours in water at a temperature of 100 degrees F. without warpage or separation of the reflective material from the support material.; Your reference to the device as a flare and to its immersion in 5 fee of water for an indefinite period makes it unclear whether you are referring to the standard as it will be effective on January 1, 1974. The final rule balanced the likelihood of water damage against numerous other considerations including cost and reuse. The 2-hour immersion requirement detailed above is intended to ensure that the device is undamaged and reuseable after an exposure to rain during any emergency deployment. In contrast, the 12-hour spray test of Standard No. 108 which you suggest as an alternative is used for reflex reflectors which are permanently mounted on a vehicle and are subject to regular and long exposure to blowing water. That spray test does not adequately simulate the relatively short but severe exposure to which a warning device would be subject in a steady rain. It is in such adverse weather conditions, of course, that the use if the device will be most important.; For these reasons, your petition is denies on the grounds tha preservation and reuse of the device justify the immersion requirement. Thank you for your interest in developing a functional warning device standard.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam4461OpenMr. Gary W. Rossow Director, Government Technical Affairs Freightliner Corporation Charlotte Technical Center 9844 Southern Pine Boulevard P.O. Box 7562 Charlotte, NC 282l7; Mr. Gary W. Rossow Director Government Technical Affairs Freightliner Corporation Charlotte Technical Center 9844 Southern Pine Boulevard P.O. Box 7562 Charlotte NC 282l7; "Dear Mr. Rossow: This responds to your letter requesting a interpretation of Standard No. l2l, Air Brake Systems. You asked whether a proposed design would meet the requirements of S5.l.2. Your question is responded to below. By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its motor vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter. Under section S5.l.2, trucks and buses are required to have the following equipment: 'Reservoirs. One or more service reservoir systems, from which air is delivered to the brake chambers, and either an automatic condensate drain valve for each service reservoir or a supply reservoir between the service reservoir system and the source of air pressure. You stated that some of your existing air braked trucks utilize a supply reservoir or wet tank between the service reservoir system and the air compressor without using automatic condensate drain valves on the service reservoirs. You noted that the supply reservoir functions as a means of removing excess water vapor from the air supply to avoid water contamination of the braking system and works on thermodynamic principles whereby water condenses to a liquid as the hot compressed air cools. Your proposed design would utilize an air dryer between the service reservoir system and the air compressor. According to your letter, the air dryer serves the same function as the supply reservoir in your existing system but works on a different principle. You stated that the moist, compressed air passes through a filter media contained in a small canister sized reservoir. The material, a desiccant, has a high chemical affinity for water. The water absorbs on the desiccant and is later purged by stored dry air. The air dryer would have an integral automatic condensate drain valve. Since your proposed design would not include an automatic condensate drain valve for each service reservoir, the issue raised by your letter is whether it complies with S5.l.2's option for 'a supply reservoir between the service reservoir system and the source of air pressure.' You stated that you believe the air dryer with automatic condensate drain is the functional equivalent of the more generally accepted embodiment of a supply reservoir in the context of S5.l.2. You also noted that Standard No. l2l does not specify a separate volume for the supply reservoir, although it does require in S5.l.2.l that the combined volume of all service reservoirs and supply reservoirs be at least l2 times the total service brake chamber volume. You suggested that if the volume of the service reservoirs is l2 times the volume of the service brake chambers, it would appear that there is no requirement for a specific volume in the supply reservoir. While Standard No. l2l does not include a definition for 'supply reservoir,' the term is one that is commonly understood. For example, you indicated in your letter that some of your current brake system designs utilize the 'more generally accepted embodiment of a supply reservoir.' In considering whether a particular item of equipment can be considered a 'supply reservoir,' we believe that effect must be given to both 'supply' and 'reservoir.' The dictionary defines 'reservoir' as 'a receptacle or chamber for holding a liquid or fluid, as oil or gas.' The word 'supply' is defined as 'to furnish or provide.' Random House Dictionary of the English Language (unabridged edition). The Society of Automotive Engineers (SAE) defines 'air reservoir' as '(a) storage container for compressed air.' SAE Recommended Practice J656g, 'Automotive Brake Definitions and Nomenclature.' Thus, in order to qualify as a 'supply reservoir,' an item of equipment must hold or store air in order to furnish or provide the air to the rest of the brake system. The information provided with your letter does not provide sufficient information to determine whether your air dryer qualifies as a 'supply reservoir.' In particular, the information does not indicate whether the air dryer holds other than a de minimis amount of air. While your letter is correct that there is no requirement for a specific volume in the supply reservoir if the volume of the service reservoirs is l2 times the volume of the service brake chambers, an air dryer with a de minimis volume could not be considered to hold or store air in order to furnish or provide the air to the rest of the brake system. On the other hand, if a supply reservoir provides an air cleaning function as well as holding or storing air in order to furnish or provide the air to the rest of the brake system, it would still be a supply reservoir. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam1399OpenMr. Robert W. Borgert, Spartan Design Inc., 24151 Telegraph Road, Southfield, MI, 48075; Mr. Robert W. Borgert Spartan Design Inc. 24151 Telegraph Road Southfield MI 48075; Dear Mr. Borgert: This is in reply to your letter of January 21, 1974 asking for ou comments on your defect notification letter.; In describing the defect (your third paragraph) as required by Sectio 577.4(c), you should state specifically that the placement of the lamps fails to conform to Federal Motor Vehicle Safety Standard No. 108, and indicate, in general terms, what is the appropriate location. In addition, section 577.4(c) requires the inclusion of precautions the purchaser can take. We believe one precaution that should be included where a lighting problem is concerned is to recommend that night driving be limited as much as possible.; When we have received a corrected copy, we will close our files in thi matter.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam1663OpenMr. Geoffrey R. Myers, Hall and Myers, Suite 200, Free State Bank Building, P.O. Box 34436, Washington, DC 20034; Mr. Geoffrey R. Myers Hall and Myers Suite 200 Free State Bank Building P.O. Box 34436 Washington DC 20034; Dear Mr. Myers: This responds to your October 22, 1974, question whether the languag of S5.3.1(b) and S5.3.2(b) in Standard No. 121, *Air brake systems*, exempts all liftable, nonsteerable axles from the 'no lockup' requirements of the standard. You specifically ask whether a liftable, nonsteerable 'tag' axle and 'pusher' axle would be exempt if they were both mounted on a vehicle equipped with a single nonliftable, nonsteerable axle or with tandem nonliftable, nonsteerable axles.; The sections in question permit 'lockup of wheels on nonsteerable axle other than the two rearmost nonliftable, nonsteerable axles on a vehicle with more than two nonsteerable axles.' This language is limited to vehicles which have more than two nonsteerable axles and therefore a liftable axle on a vehicle with only one other nonsteerable axle would not be exempt. Such a combination can be found on some intercity buses.; In both of the examples you describe the vehicle has more than tw nonsteerable axles, and therefore the language of S5.3.1(b) and S5.3.2(b) would exempt the tag and pusher axles from the 'no lockup' requirements of the standard. I would like to emphasize, however, that our language is intended to require 'no lockup' performance on not less than two nonsteerable axles of any vehicle with at least two nonsteerable axles. We did not contemplate the unlikely configuration of a single fixed axle and two liftable axles which you cite as an example. If a safety problem arises with this configuration, we would consider an amendment of the standard to require 'no lockup' performance of two of these axles.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0971OpenMr. W. S. Magenau, President, Chesapeake Marine Products, Route 256, Deale, MD 20751; Mr. W. S. Magenau President Chesapeake Marine Products Route 256 Deale MD 20751; Dear Mr. Magenau: This is in reply to your letter of December 18, 1972, requestin information as to how a distributor who assembles a boat trailer may certify the trailer under NHTSA requirements, when the weight ratings for the trailer when assembled differ from those anticipated by the fabricator, due to the distributor's use of components (tires and springs) of a greater weight-carrying capability than those envisioned by the fabricator.; The certification requirements applicable to the manufacture of boa trailers are found at section 567.4, 'Requirements for Manufacturers of Motor Vehicles'. The fabricator may affix the required label to a trailer in certain cases (section 567.4(f)(ii)), but in the case you describe, where the distributor assembles the vehicle in a manner not specifically anticipated by the fabricator, the assembler is the appropriate person, pursuant to S 567.4(g)(1), to certify the vehicle and affix the certification label. The label should state the name of the assembler (the distributor) as the manufacturer and reflect the weight ratings of the vehicle as assembled.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5620OpenMr. Joseph J. Smith Assistant Chief Maintenance Officer New York City Transit Authority 25 Jamaica Avenue Brooklyn, NY 11207; Mr. Joseph J. Smith Assistant Chief Maintenance Officer New York City Transit Authority 25 Jamaica Avenue Brooklyn NY 11207; "Dear Mr. Smith: This responds to your inquiry about whether Federa Motor Vehicle Safety Standard No. 302, Flammability of Interior Materials (49 CFR 571.302), applies to air conditioning return air filters. You state that these filters are placed on top of the air conditioning evaporator coil and are separated from the bus interior by a louvered panel. You were concerned that the filters may be subject to Standard No. 302 because they may be considered located in the 'occupant compartment air space.' As explained below, Standard No. 302 does not apply to air conditioning return filters. By way of background information, NHTSA is authorized to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, Congress has established a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. Since Standard No. 302 is a vehicle standard, the manufacturer of the vehicle, and not the manufacturer of the individual component, is responsible for certifying compliance with Standard No. 302. The agency periodically tests new vehicles and items of equipment for compliance with the standards. Standard No. 302 specifies burn resistance requirements for materials used in the occupant compartment of new motor vehicles. Section S4.1 lists the components in vehicle occupant compartments that the vehicle manufacturer must certify as complying with the flammability resistance requirements of paragraph S4.3. The components listed include seat cushions, seat backs, seat belts headlining, convertible tops, arm rests, all trim panels including door, front, rear, and side panels, compartment shelves, head restraints, floor coverings, sun visors, curtains, shades, wheel housing covers, engine compartment covers, and any other interior materials, including padding and crash deployed elements, that are designed to absorb energy on contact by occupants in the event of a crash. Section S4.1 represents a complete listing of all components in new vehicles that must comply with the flammability resistance requirements. Any component not identified in section S4.1 is not subject to those requirements. Therefore, an air conditioning return filter is not subject to those requirements. Please note that there are other NHTSA requirements that could affect the manufacture and sale of products related to motor vehicles. A motor vehicle or equipment manufacturer incorporating air conditioning filters in its vehicles or equipment would be subject to 49 U.S.C. 30118-30121 to ensure that its vehicles or equipment do not contain any safety related defect. If the manufacturer or NHTSA determines that a safety related defect exists, the manufacturer would be responsible for notifying purchasers of the defective vehicle or equipment and remedying the problem free of charge. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam4932OpenDeborah K. Nowak-Vanderhoef, Esq. General Motors Corporation Legal Staff New Center One Building 3031 West Grand Boulevard P.O. Box 33122 Detroit, MI 48232; Deborah K. Nowak-Vanderhoef Esq. General Motors Corporation Legal Staff New Center One Building 3031 West Grand Boulevard P.O. Box 33122 Detroit MI 48232; "Dear Ms. Nowak-Vanderhoef: This responds to your request for a interpretation of Standard No. 209, Seat Belt Assemblies (49 CFR 571.209). Specifically, you asked if General Motors Corporation (GM) could include the term 'dynamically-tested' in the label required by S4.6(b) of Standard No. 209. The answer is that GM may do so. Prior to September 1, 1992, S4.6(b) of Standard No. 209 requires a dynamically tested manual belt to be labeled with the following statement: 'This dynamically-tested seat belt assembly is for use only in (insert specific seating position(s), e.g., front right) in (insert specific vehicle make(s) and model(s)). However, a November 4, 1991 final rule, published at 56 FR 56323, amended S4.6(b) by deleting the term 'dynamically-tested' from the required label, effective September 1, 1992. GM would like to continue to include the term 'dynamically-tested' on its labels. NHTSA has often addressed the issue of whether additional information may be provided along with information that is required to be labeled on the product in the context of our safety standards that apply to tires. NHTSA has consistently stated that additional information may be included on tires, provided that the additional information 'does not obscure or confuse the meaning of the required information, or otherwise defeat its purpose.' See, e.g., our May 31, 1988 letter to Mr. Garry Gallagher of Metzeler Motorcycle Tire. This is the same test we would apply in any of our safety standards for additional information that is provided along with required labeling information. Applying this test to the situation at hand, the purpose of the labeling requirements in Standard No. 209 is to minimize the likelihood of improper installations of dynamically-tested manual belts, by specifying the particular vehicles and seating positions in which the belts are designed to be installed. GM's proposed labels would provide the information about the particular vehicles and seating positions in which the belts are designed to be installed on the label of these belts. The only difference between GM's proposed labels and the exact language specified in S4.6(b) of Standard No. 209 would be that GM's proposed labels would describe the belts as 'dynamically-tested seat belt assemblies,' instead of 'seat belt assemblies.' We do not see how this additional description of the belts, which is accurate and consistent with the agency's use of the term 'dynamically-tested,' would obscure or confuse the meaning of the required information or otherwise defeat its purpose. Therefore, GM's proposed labeling would be permitted under the provisions of S4.6(b) of Standard No. 209 that take effect September 1, 1992. Enclosed with your letter was a petition for reconsideration that you asked be considered if the agency determined that the current language of S4.6(b) of Standard No. 209 prohibited the additional information to be provided on the GM labels. Since NHTSA has concluded that Standard No. 209 permits the additional information, we are disregarding that petition for reconsideration and will take no action on it. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0422OpenMr. J. A. Shuman, Safety and Environment Manager, International Harvester Company, Motor Truck Division, 401 North Michigan Avenue, Chicago IL 60611; Mr. J. A. Shuman Safety and Environment Manager International Harvester Company Motor Truck Division 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Shuman: This is in reply to your letter of March 18, 1971, petitioning fo reconsideration of the 'Defect Reports' regulations (Docket No. 69-31, Notice 2). Your letter was received on March 22, 1971, which is more than 30 days after publication of the regulation. Accordingly, pursuant to NHTSA procedural rules (49 CFR S 553.35), it has been treated as a petition for rulemaking.; You request that the requirements specified in A 573.4(b), that defec information reports be submitted not more than 5 working days after a defect in a vehicle has been determined to be safety related, be changed to require the report to be submitted not later than 15 days after the determination has been made. You state as the basis for this requested change that the information required pursuant to S 573.4(c)(3) and S 573.4(c)(7) cannot be provided by International Harvester within 5 days due to computer run-out times, but can be provided within 15 days. Section 573.4(b) of the regulation provides, as you point out, that information required pursuant to S 573.4 that is not available within 5 days may be submitted as it becomes available. This provision deals with the issue you raise, and no amendment to the regulation is called for.; With reference to your statement that the figures you intend to repor pursuant to S 573.5(c)(6) and (c)(7) will be identical, the regulation requires different kinds of information to be reported. Only if the information required by SS 573.5(c)(6) and (c)(7) is in fact identical may it be reported as such. The requirements are not intended necessarily to fit within the framework of manufacturers' presently existing data gathering procedures, and may require some manufacturers to change these procedures to provide the specific information.; Sincerely, Robert L. Carter, Acting Associate Administrator, Moto Vehicle Programs; |
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.