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: aiam0987OpenMr. Ross M. Smith, Midwest Business Forms, Inc., 4900 North River Road, Schiller Park, IL 60176; Mr. Ross M. Smith Midwest Business Forms Inc. 4900 North River Road Schiller Park IL 60176; Dear Mr. Smith: This is in reply to your letter of February 5, 1973, concerning th odometer disclosure form that you propose to print in accordance with the Federal odometer Disclosure Requirements, 49 CFR 580.; As you indicate, the proposed form conforms in all respects to the for specified in S 580.6, except that it provides additional space for the State and year of the last plate. We find that these items will help identify a vehicle, and that their inclusion is consistent with the purpose of the form. We therefore do not object to their inclusion on the form.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3702OpenMr. Roger E. Maugh, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. Roger E. Maugh Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Maugh: This responds to your letter of June 2, 1983, regarding Ford's desir to equip 2,500 of its vehicles with Securiflex windshields to obtain field data regarding glass- plastic glazing. You state that such a test fleet would provide Ford with information regarding concerns it has about in-plant handling, vehicle assembly, mirror attachment, haze, scratching, delamination durability, and performance in accidents.; As you are probably aware, General Motors made a similar reques regarding a test fleet of Securiflex windshields last fall. We can give Ford the same assurances that were given to General Motors in response to their request. Under the limited and special circumstances of the field test described in your letter, the agency can firmly state that it would not enforce the abrasion requirement of Safety Standard No. 205 as it now stands since it does not appear to be appropriate for technology like the Securiflex windshield (Securiflex apparently cannot pass the existing abrasion requirements). That technology was developed after the standard was originally issued, and the standard did not contemplate assymetrical (sic) glazing of this type. Equally important, the agency notes that all current information indicates that glass- plastic glazing does have a great potential for reducing lacerative injuries in accidents. The experimental use which you propose should provide valuable information regarding injury reduction and some of the remaining problems which do appear to exist with regard to this type windshield. We also note your statement that the Securiflex windshields you plan to install on the test fleet would comply with the proposed requirements for glass-plastic glazing issued by the agency March 10, 1983 (48 FR 10097).; In light of the agency's policy decision to foster the use of ne safety technology by permitting the field test you propose, the agency expects your company to monitor closely the test fleet and to rectify any problems that may develop. Ford would, of course, remain responsible for meeting its obligation under the Vehicle Safety Act regarding any safety related defects. The agency also expects to be apprised of all information that Ford obtains from this field test.; Sincerely, Diane K. Steed, Acting Administrator |
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ID: aiam2810OpenMr. Edwin S. Kirby, The Johnson Manufacturing Co., 605 Miami Street, Urbana, OH 43078; Mr. Edwin S. Kirby The Johnson Manufacturing Co. 605 Miami Street Urbana OH 43078; Dear Mr. Kirby: This responds to Johnson Manufacturing's May 4, 1978, request fo confirmation that the requirement in Standard No. 121, *Air Brake Systems*, that reservoirs 'withstand' specific pressure does not require testing of a multi-compartment reservoir compartment-by-compartment.; Your understanding of the 'withstanding' requirement in S5.1.2.2 an S5.2.1.3 is correct. Although the agency sought to clarify that compartment-by-compartment testing was the proper interpretation of this requirement (42 FR 64630, December 27, 1977), problems with the interpretation resulted in its withdrawal (43 FR 9149, March 6, 1978) and adherence to the existing interpretation that there be no rupture or permanent circumferential deformation of the reservoir. Under this interpretation only the circumference of the outer reservoir shell is measured, and internal baffles are not stressed by separate compartment-by-compartment testing.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5286OpenMr. C.N. Littler Coordinator-Regulatory Affairs MCI/TMC Engineering Centre 1558 Willson Place Winnepeg, Manitoba R3T 0Y4; Mr. C.N. Littler Coordinator-Regulatory Affairs MCI/TMC Engineering Centre 1558 Willson Place Winnepeg Manitoba R3T 0Y4; "Dear Mr. Littler: This responds to your FAX and phone call of July 30 1993 to Mary Versailles of my office. Your FAX enclosed information on a vehicle, the AMF Invader, which is built on a remanufactured MCI chassis, and advertised and sold as a new vehicle. You do not believe that such a vehicle should be considered a new vehicle. As Ms. Versailles explained on the phone, we can explain whether such a vehicle would be considered a new vehicle for purposes of laws and regulations administered by this agency, and the implications of such a determination. I suggest you also contact the Federal Trade Commission concerning whether it is appropriate to advertise this vehicle as new. To determine whether this vehicle can be titled and registered as new, you would have to contact the various states concerning their laws. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) to issue Federal motor vehicle safety standards that apply to the manufacture and sale of 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 any person from manufacturing, introducing into commerce, selling, or importing any new motor vehicle or item of motor vehicle equipment unless the vehicle or equipment item is in conformity with all applicable safety standards. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor does it endorse any commercial products. Instead, the Safety Act establishes a self-certification process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. After a vehicle's first retail sale, a provision affecting its modification is section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(2)(A)) which 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. It is possible that modifications on an existing vehicle may be so substantial that the resulting vehicle would be a new vehicle for purposes of compliance with the safety standards. In this case, the new vehicle would be required to be certified by its manufacturer as complying with all applicable safety standards in effect on its date of manufacture, just like every other new vehicle. This date would be the date such modifications were completed. The agency has stated that a bus built with a new body is not considered a 'new' vehicle if, at a minimum, the engine, transmission, and drive axle(s) are not new and at least two of these three listed components are taken from the same used vehicle (see, for example, August 11, 1987 letter to Mr. Ernest Farmer). The agency has also stated that a bus constructed from an old body and a new chassis is a new vehicle (see, for example, July 17, 1981 letter to Mr. Larry Louderback). When neither the body nor the chassis are completely new, the agency looks to see if the vehicle has so deviated from the original components and attributes that it may be considered a new vehicle, and one for which compliance with the safety standards is legally required, or whether it has retained a sufficient number of components and characteristics to be considered a used vehicle (see, for example, April 22, 1991 letter to Mr. Kent Morris). You enclosed an article titled 'The New Invader' from the August 1993 issue of National Bus Trader magazine. The manufacturing process for the Invader is described beginning on page 14. Page 16 of this article states, 'the Invader is supplied with a new engine,' but the article does not contain enough information to determine whether the vehicle, which includes both new and old parts, would be considered new. If the Invader has a new body, NHTSA would considered the vehicle to be new if the chassis lacks the used components referenced in the Farmer letter. Any new vehicle must be certified as complying with all applicable safety standards in effect on the date of manufacture before the vehicle can be sold in the United States. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel cc: AMF 1830 LeBer Street, Montreal Quebec, Canada H3K 2A4"; |
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ID: aiam2543OpenMr. R. A. Bynum, Supervisor, Pupil Transportation Service, Commonwealth of Virginia, State Department of Education, Richmond, VA 23216; Mr. R. A. Bynum Supervisor Pupil Transportation Service Commonwealth of Virginia State Department of Education Richmond VA 23216; Dear Mr. Bynum: This responds to your February 18, 1977, letter asking whether Standar No. 222, *School Bus Passenger Seating and Crash Protection*, permits the use of a two-passenger front-row seat with a corresponding two-passenger front-row restraining barrier. Secondly, you ask whether the State of Virginia can require the use in joints of discrete fasteners and welding, and not adhesives, without conflicting with the requirements of Standard No. 221, *School Bus Body Joint Strength*. Finally, you ask who must certify that a vehicle complies with Standard No. 105, *Hydraulic Brake Systems*.; The NHTSA has issued an interpretation allowing the use of a two passenger front-row seat with a two-passenger restraining barrier. This can be accomplished by the use of a two-passenger seat cushion and a three-passenger seat back as you suggest. I am enclosing a copy of the NHTSA interpretation for your information.; Regarding your second question concerning the use of adhesives in bu body joints, the Federal bus body joint standard requires only that joints meet a specified strength requirement. The NHTSA does not require any particular type of joint construction. Therefore, the purchaser and manufacturer can decide upon any method of joint construction as long as the joint meets Federal strength specifications.; Your final question asks who must certify that a small school bu (under 10,000 pounds) is in compliance with Standard No. 105, *Hydraulic Brake Systems*. To assign responsibility for the certification of multi-stage vehicles, NHTSA has issued Part 568, *Vehicles Manufactured in Two or More Stages* (enclosed). The manufacturer of an 'incomplete-vehicle' (such as a cab-chassis) must provide documentation to the intermediate- and final-stage manufacturer of the vehicle on how to complete it so that it complies with all applicable standards. It is the responsibility of the final- stage manufacturer to affix a certification label unless the incomplete- or intermediate-stage manufacturer assumes this responsibility.; On a related matter concerning small school buses, it is ou understanding that school buses weighing under 10,000 pounds will be available after April 1, 1977.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0084OpenMr. George W. S. Smith, President, Ideal Manufacturing Company, 1107 South Seventh Street, Oskaloosa, IA 52577; Mr. George W. S. Smith President Ideal Manufacturing Company 1107 South Seventh Street Oskaloosa IA 52577; Dear Mr. Smith: Thank you for your letter of June 10, 1968, to Mr. J. O'Gorman of thi Bureau, concerning the requirements for side reflex reflectors as specified in Motor Vehicle Safety Standard 108.; As noted in your letter, paragraph S3.1.1.6 of Standard No. 108 effective January 1, 1969, permits until January 1, 1970, the use of two side reflex reflectors on each side of vehicles that are less than 80 inches in overall width. On and after January 1, 1970, Standard No. 108 requires that these vehicles be equipped on each side with two side reflex reflectors and two side marker lamps.; Thank you for writing. Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam2113OpenMr. Lee, Tong Shin Chemical Products Co., Ltd., 325 - 12th Street, Palisades Park, New Jersey 07650; Mr. Lee Tong Shin Chemical Products Co. Ltd. 325 - 12th Street Palisades Park New Jersey 07650; Dear Mr. Lee: This is in response to your inquiry concerning the addition of th symbol 'DOT' to tires imported into this country, and in confirmation of your telephone conversation with Mr. Schwartz of this office.; 49 CFR Part 574, Tire Identification and Recordkeeping, requires tir manufacturers to permanently mold into or onto the sidewall of tires an identification number and the symbol DOT. The position of the identification number and DOT symbol is illustrated in Figures 1 and 2 of the Regulation. The symbol DOT, as stated in Motor Vehicle Safety Standard No. 109, New Pneumatic tires, 49 CFR 571.109, constitutes a certification that the tire conforms to all applicable safety standards.; Neither Standard No. 109 nor Part 574 prohibit the branding of th symbol DOT onto the tire after manufacture, as long as the information becomes part of the actual sidewall material. By branding the symbol DOT onto the tire you are certifying that the tires meet all the requirements of the motor vehicle safety standards based on information which, in the exercise of due care, you know to be accurate.; If you have further questions concerning this matter, please do no hesitate to contact me.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5639OpenMr. Larry W. Strawhorn Vice President of Engineering American Trucking Associations 2200 Mill Road Alexandria, VA 22314-4677; Mr. Larry W. Strawhorn Vice President of Engineering American Trucking Associations 2200 Mill Road Alexandria VA 22314-4677; "Dear Mr. Strawhorn: This letter responds to your request for a interpretation of the antilock power circuit requirements set forth at S5.1.6.3 of Standard No. 121, Air Brake Systems. This provision states that S5.1.6.3 Antilock Power Circuit for Towed Vehicles. Each truck tractor manufactured on or after March 1, 1997 and each single unit vehicle manufactured on or after March 1, 1998 that is equipped to tow another air-braked vehicle shall be equipped with one or more separate electrical circuits, specifically provided to power the antilock system on the towed vehicle(s). Such a circuit shall be adequate to enable the antilock system on each towed vehicle to be fully operable. (Emphasis added.) You believe that the phrase 'separate electrical circuit' allows for the continued use of the single SAE J560 connector if one of the seven pins provides full-time power for the ABS. You further believe that the ABS malfunction signal can be multiplexed on any circuit of the connector and that the other trailer devices can be powered off the circuit as long as the circuit is adequate to enable the antilock system on each towed vehicle to be fully operable. In the March 10, 1995 final rule, NHTSA decided to adopt the proposed full-time power requirement for trailer ABSs. (60 FR 13216) The agency explained that it amended the standard's wording to clarify that towing vehicles must have a corresponding separate circuit specifically provided to power the antilock system on the towed vehicle or vehicles. The agency stated that requiring a separate circuit 'will ensure the strongest possible source of electrical power from the tractor to ensure the functioning of all the ECUs and modulators that are employed in the antilock brake system, or systems, on single trailers, or multiple trailers and converter dollies in multi-trailer combinations. It also stated that this requirement will ensure a continuous malfunction indication whenever a malfunction exists. The agency further stated that it has left the decision about which type of connector should be used to the industry. In response to your question about the use of one of the pins in the seven-pin connector to provide full-time power for the ABS, the use of such a pin would be permissible provided that the pin services a 'separate' electrical circuit to 'specifically provide' full time power for the trailers in combination vehicles. This means that the circuit's sole function must be to provide ABS powering, i.e., other trailer devices may not be powered off this separate electrical circuit. This would preclude the use of the pin to power the ABS malfunction signal. Since the requirement for the ABS malfunction circuit did not specify that the circuit used for transmitting the malfunction signal be a 'separate' one, ABS malfunction signals can be multiplexed on other circuits with pins in the electrical connector, but not on the circuit and pins used to power the ABS system. It is important to note that the ABS semitrailer fleet study report (DOT HS 808 059) concluded that the voltages delivered by powering system approaches that employed dedicated separate circuits (i.e., the Cole Hersee, ISO, and 6-pin auxiliary systems) were well within the required limits for ECU powering, whereas, the voltages delivered through the stoplamp circuit did not perform as well. The agency concluded that these data indicate the superiority of a separate circuit powering of the trailer ABS and therefore, justify the separate circuit requirement. As you are aware, NHTSA received several petitions for reconsideration about the separate electrical circuit. The agency anticipates that the final rule in response to these petitions for reconsideration will have a detailed discussion of these requirements. In addition, the agency may decide to modify these requirements. I hope this information has been helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992. Sincerely, Samuel J. Dubbin Chief Counsel"; |
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ID: aiam2406OpenMr. Kenneth C. Ploeger, President, ACUTEK, 5th & Dryden, Odessa, MO, 64076; Mr. Kenneth C. Ploeger President ACUTEK 5th & Dryden Odessa MO 64076; Dear Mr. Ploeger: This is in reply to your letter of October 13, 1976, to Mr. Lewis C Owen, Safety Standards Engineer, concerning an interpretation of the words 'optically combined' as they apply to your Acutek 301 combination rear lamp.; In the Acutek lamp, the data you submitted indicate that when th taillamp bulb is activated independently from the clearance lamp bulb, and vice versa, there is no appreciable amount of incidental light emitted from the lens of the clearance lamp. The amount of light 'spill' appears to be so small that it would not be interpreted (by a driver following the vehicle on which it is installed) as illuminating the lens of the taillamp when operated in the clearance lamp mode, and vice versa.; Accordingly, the Acutek 301 combination rear lamp appears to meet th requirements of Federal Motor Vehicle Safety Standard No. 108, 'Lamps, Reflective Devices, and Associated Equipment.'; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam0591OpenMr. Jerry Warner, Manager, Foam Sales & Engineering, Keyston Brothers, 1000 Brannan Street, San Francisco, CA, 94103; Mr. Jerry Warner Manager Foam Sales & Engineering Keyston Brothers 1000 Brannan Street San Francisco CA 94103; Dear Mr. Warner: This is in reply to your letter of February 9, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' to an interior upholstered panel that you manufacture. You state that the panel is made up of a vinyl surface, a self-extinguishing foam, and a backing, and that the three materials must be tested as a single unit, or separately.; Paragraph S4.2 of Standard No. 302 specifies as follows:>>>S4.2 Th portions of the components that shall meet the requirements of S4.3 are all of the following:; (a) The surface material taken separately if it is not bonded, sewed o mechanically attached to underlying material.; (b) A composite consisting of the surface material bonded, sewed o mechanically attached to underlying material, if such a composite is used in the component.; (c) Padding and cushioning materials taken separately, if thos materials are not bonded, sewed or mechanically attached to surface materials.<<<; Under the language of S4.2, your surface material, and the underlyin foam should be tested as a composite pursuant to subparagraph (b). If the backing is considered a padding or cushioning material, it should be tested separately pursuant to subparagraph (c).; A notice of proposed rulemaking which would amend paragraph S4.2 wa published May 26, 1971 (36 F.R. 9565), and a copy is enclosed for your information. We expect that a final rule based on this proposal will be published in the near future. Under the wording of the proposal your material would be tested under subparagraph (b) to a depth of 1/2 inch, and padding and cushioning material would be tested again under subparagraph (c).; We are pleased to be of assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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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.