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: aiam1134OpenMr. Doran Rhodes, Assistant to the President, Highway Aircraft Corporation, 909 Fifth Avenue, Box 651, Sidney, NE 69162; Mr. Doran Rhodes Assistant to the President Highway Aircraft Corporation 909 Fifth Avenue Box 651 Sidney NE 69162; Dear Mr. Rhodes: This is in reply to your letter of April 24, 1973, to Mr. Schneide asking for an interpretation that the Fascination vehicle your company proposes to manufacture is 'an automobile.' You state that you 'are currently testing both a single wheel and a dual wheel arrangement in the front, and it is not clear yet which one will prevail.'; If the final configuration of the Fascination were that of four-wheeled vehicle it would be categorized as a 'passenger car' under the Federal Motor Vehicle Safety Standards. Currently all three-wheeled vehicles are classified under our regulations as 'motorcycles.' Under a recent rule making proposal, a copy of which I enclose, the definition of a motorcycle with three wheels would be restricted to those lacking a full or partial enclosure for the driver, clearly excluding the Fascination. If the proposal is adopted, and you choose the three-wheel configuration for the Fascination, then the vehicle would probably be classified as a passenger car. It is possible that some adjustments would be made in the standards applied to three-wheeled or other lightweight vehicles, on petitions received from those interested.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1336OpenMr. R.O. Crider, Manager, Government Safety Standards and Regulations Compliance, Fruehauf Corporation, P.O. Box 238, Detroit, MI 48232; Mr. R.O. Crider Manager Government Safety Standards and Regulations Compliance Fruehauf Corporation P.O. Box 238 Detroit MI 48232; Dear Mr. Crider: Thank you for your letter of November 20, 1973, asking whether you ma install 'lights as set forth in Example 1.' In this example identification lamps would be mounted under the rear crossmember of the vehicle while 'the combination tail and turn signal lamps (at the bottom) could serve as the clearance lamps.'; The rear lighting scheme shown in your 'Example 1' appears to b seriously at variance with Standard No. 108. There is a clear violation of paragraph S4.4.1 which forbids the optical combination of tail lamps and clearance lamps. Both clearance lamps and identification lamps must be located 'as close as practicable to the top of the vehicle.' The fact that you have developed a clearance lamp that can be mounted in the header area demonstrates that that is the 'practicable' location, despite the fact that the header may be too shallow to accommodate the lamps specified by the customer. Further, since the performance required of clearance lamps is identical to that for identification lamps, and three of your clearance type lamps could serve as identification lamps, the header would appear to be the 'practicable' location for the identification lamp arrangement as well.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam1882OpenMr. James L. Srch, Chief Engineer, Hendrickson Manufacturing Company, 8001 West Forty-Seventh Street, Lyons, IL 60534; Mr. James L. Srch Chief Engineer Hendrickson Manufacturing Company 8001 West Forty-Seventh Street Lyons IL 60534; Dear Mr. Srch: I am writing in response to your letter of March 25, 1975, in which yo request advice as to whether you should establish gross axle weight ratings and gross vehicle weight ratings based on the 55 mph national speed limit or on the maximum attainable speed of the vehicle.; The Gross Axle Weight Rating (GAWR) and the Gross Vehicle Weight Ratin (GVWR) are defined by the National Highway Traffic Safety Administration (NHTSA) as determinations made by the manufacturer. (49 CFR 3571.3). As a general matter NHTSA finds that the manufacturer is most familiar with the complexities of this product and is most qualified to assign these values.; Recently NHTSA has found it necessary to specify that GAWR's and GVWR' be calculated on the basis of highway speeds and not qualified by reduced speed ratings, our reasons for this action are contained in the enclosed letter. For purposes of GAWR-GVWR calculations, NHTSA will henceforth consider 'highway speed' to be the 60 mph value used by the United States Tire and Rim Association in assigning unqualified ratings to their tires.; Therefore, your trucks and buses which are capable of speeds of 60 mp or more should be assigned ratings which reflect vehicle capabilities at 60 mph.; Sincerely, James B. Gregory, Administrator |
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ID: aiam0704OpenMr. Harvey Livingston, Livingston's Tire Shop, North Main Street, Hubbard, Ohio 44425; Mr. Harvey Livingston Livingston's Tire Shop North Main Street Hubbard Ohio 44425; Dear Mr. Livingston: This is in reply to your letter of May 2, 1972, requesting a lette from NHTSA to the effect that tire manufacturers are free to sell you new repairable tires which you plan to repair and sell. We have assumed that the manufacturers of the tires do not believe that they conform to Motor Vehicle Safety Standard No. 109. 'New Pneumatic Tires,' and that they have not certified conformance to the standard, as this is apparently the reason for their reluctance to sell you these tires.; Paragraph S6. of Standard No. 109 provides, among other things, tha passenger car tires that are not certified, defined as 'reclassified tires,' must bear a label (specified in the standard) stating that they are not to be sold for use on passenger cars.; If you wish to purchase reclassified tires, repair them, and resel them for passenger car use, you must ensure that they conform to the performance requirements of Standard No. 109 (paragraphs S1. through S5.). and relabel and certify them in accordance with paragraph S4.3.; You should be aware that the NHTSA has proposed, in a notice date November 27, 1971 (36 F.R. 22688, copy enclosed) to prohibit the sale for any purpose of reclassified tires.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2224OpenEdward Lacey, Industry Technical Specialist, Laminated Glass, Monsanto Polymers and Petrochemicals Co., 190 Grochmal Avenue, Indian Orchard, MA 01051; Edward Lacey Industry Technical Specialist Laminated Glass Monsanto Polymers and Petrochemicals Co. 190 Grochmal Avenue Indian Orchard MA 01051; Dear Mr. Lacey: This is in response to your letter of December 22, 1975, to Mr. Gu Hunter of my staff, concerning our reasons for prohibiting the use of tempered glass in windshields of motor vehicles.; The use of tempered glass in windshields is prohibited for th following reasons:; >>>1. Tempered glass has little, if any, energy absorbing capabilit while laminated glass has intrinsic deflective characteristics that provide such capability.; 2. When tempered glass breaks, it usually either 'crazes' or shatter into many small pieces. If crazing occurs, the driver's vision becomes obscured thus not only endangering himself but others as well. If the glass shatters, the driver and other vehicle occupants are showered with glass pellets which could not only result in loss of control of the vehicle but is also likely to cause eye injuries.; 3. When cracked, tempered glass has essentially no retentiv capability, thus the likelihood of occupant ejection through the windshield opening is greatly increased in crash situations. Laminated glass, on the other hand, possesses significant retentive capability even after initial cracking of the glass laminate on either side of the plastic interlayer.<<<; If I can be of further help, do not hesitate to contact me. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam0913OpenMr. Gorou Utsunomiya, Branch Manager, Toyo Kogyo USA Rep. Ofc. Det. Branch, 23777 Greenfield Rd., Suite 462, Southfield, MI 48075; Mr. Gorou Utsunomiya Branch Manager Toyo Kogyo USA Rep. Ofc. Det. Branch 23777 Greenfield Rd. Suite 462 Southfield MI 48075; Dear Mr. Utsunomiya:#This is in reply to your letter of October 13 1972, asking a question concerning the location of the identification of the fan control as proposed by Docket No. 1-18, Notice 7. Under the system discussed in your letter, the word 'FAN' would be located on the control panel and illuminated. An additional 'FAN' would appear on the control itself but would not be illuminated.#The NHTSA proposal would require identification of the 'fan control' with the word 'FAN', and that this identification be illuminated. Paragraph S4.2.1 of Standard No. 101 requires that identification be placed on or adjacent to the control. The control panel of your system appears adjacent to the control, and where identification is placed both on and adjacent to the control, illumination of either will meet the proposed requirements.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam0174OpenMr. David A. Zawolkow, Staff Engineer, Challenge-Cook Bros. Incorporated, 15421 East Gale Avenue, Industry, CA 91745; Mr. David A. Zawolkow Staff Engineer Challenge-Cook Bros. Incorporated 15421 East Gale Avenue Industry CA 91745; Dear Mr. Zawolkow: This is in response to your letter of August 12, 1969, concerning th responsibility of manufacturers who assemble work bodies such as concrete mixers to chassis-cabs produced by another company. You stated:; >>>'We understand that in the case of installing concrete mixers of ou manufacture on a chassis vehicle, our certification will cover only those Safety Standards relating to our own equipment and its installation, plus modifications, if made by us to the chassis vehicle in the area where Safety Standards apply.'<<<; As a final-stage assemblies you are responsible for any standard applicable to the completed vehicle to which conformity has not been certified by the chassis-cab manufacturer, and for any standards conformity to which is affected by the addition of the body. The chassis- cab manufacturer is required to affix an label listing the standards the chassis-cab conforms to. If the list includes all relevant standards, and you have no specific knowledge that the chassis-cab may not conform (as, for example, where it has been damaged in transit), then your statement above is essentially correct.; The relevant rulings are contained in the Federal Register notices o January 3, 1968, together with the certification regulations published July 9, 1969. Copies are enclosed.; Sincerely, David E. Wells, Chief Counsel |
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ID: aiam1238OpenMr. Richard Hrejsa, 4531 Grove Avenue, Brewyn, IL 60402; Mr. Richard Hrejsa 4531 Grove Avenue Brewyn IL 60402; Dear Mr. Hrejsa: This is in response to your letter of June 4, 1973, requestin information on remedies for a transferor's failure to make an accurate odometer disclosure statement. I apologize for our delay in replying.; Title IV of the Motor Vehicle Information and Cost Savings Act, Publi Law 92-513, (1) prohibits the resetting or altering of an odometer to change the miles indicated on it, and (2) establishes a requirement that a transferor (seller) make a written odometer disclosure to his transferee (buyer) at the time of sale. These provisions of the law were in effect when you purchased your car in May 1973.; The two remedies for violations of the law are (1) a private civi action for $1,500 or treble damages by a subsequent purchaser of the car, and (2) a suit by the Untied States Attorney to restrain further violations of the Act. This second remedy is normally utilized only in the case of repeated violations.; If the dealer who sold you the car altered or reset the mileage afte January 18, 1973, you may have a civil action against him. Also, if it is as it appears in your letter, the dealer made a false and incomplete mileage disclosure to you after March 1, 1973, which may also make him civilly liable to you. His purchase of the car in October 1972 has no bearing on his disclosure obligations to you.; You may wish to consult with an attorney about your rights in thi matter. Enclosed are a copy of the Act and implementing regulations for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5499OpenHerr Tilman Spingler Robert Bosch GmbH FAX 49-7121-35-1792; Herr Tilman Spingler Robert Bosch GmbH FAX 49-7121-35-1792; Dear Herr Spingler: We have received your FAX of February 15, 1995 asking whether a proposed design 'for a lens-reflector-joint can be considered as conforming to the appropriate definition in FMVSS 108.' The agency does not advise manufacturers whether particular designs are regarded as 'conforming.' That determination is to be made by the manufacturer in certifying that its product conforms to all applicable Federal Motor Vehicle Safety Standards. However, we can provide you with an interpretive guideline. Section S4 defines a 'replaceable bulb headlamp' as a headlamp 'comprising a bonded lens reflector assembly and one or two replaceable light sources.' The intent of the definition was that the lens and reflector assembly be an indivisible unit upon manufacture of the headlamp. This means that, if a lens is broken, the entire lens reflector assembly must be replaced. If your design is such that the lens cannot be removed from the reflector assembly for replacement, it would appear to meet the definition in S4. As you are well aware, NHTSA granted your company's petition for rulemaking, and, in November 1994, proposed an amendment of the definition of 'replaceable bulb headlamp' that would allow a replaceable lens if the headlamp incorporates a vehicle headlamp aiming device conforming to S7.8.5.2. Comments were due on this proposal February 21, 1995. In due course, after review of the comments, NHTSA will decide whether it will pursue further rulemaking or terminate the rulemaking action. Sincerely, Philip R. Recht Chief Counsel; |
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ID: aiam0265OpenMr. B. Borisoff, Consulting Engineer, 5403 Blanco Avenue, Woodland Hills, CA 91364; Mr. B. Borisoff Consulting Engineer 5403 Blanco Avenue Woodland Hills CA 91364; Dear Mr. Borisoff: Reference is made to your letter of October 14, 1970 to Secretary Volp regarding our Consumer Information publication.; Concerning your comments on stopping distance, the wording used on pag 4 is the exact wording of this regulation. The category 'Stopping distance in feet with emergency brakes (partial service brake system)' is a generalization of the regulatory wording meant to convey the sense of this requirement to a consumer who may have no engineering background. The paragraph on page 193 paraphrases the regulatory wording. The title 'Partial Failure on One System' is, again, meant to convey the meaning to an otherwise uninformed consumer. I trust this clarifies the situation for you.; The reason many motorcycles are not listed is the fact that the dat was not received in time to be included in the book. I am enclosing copies of the data available for U.S. made motorcycles as you requested.; Volume 2, covering the 1971 makes and models will be availabl approximately November 15, 1970 and can be obtained from the Government Printing Office at a cost of $2.00. In addition two (2) new Consumer Aid publications entitled 'BRAKES - A Comparison of Braking Performance for 1971 Passenger Cars' and 'TIRES - A Comparison of Tire Reserve Load for 1971 Passenger Cars' will also be available at a cost of $.40 each.; Many thanks for your kind words and your interest in our motor vehicl safety program.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl 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.