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: aiam1051OpenMr. R. W. Lillie, 3345 Wilshire Boulevard, Suite 204, Los Angeles, CA 90010; Mr. R. W. Lillie 3345 Wilshire Boulevard Suite 204 Los Angeles CA 90010; Dear Mr. Lillie: Thank you for your letter of January 30, 1973, and our sincer apologies for the delay in responding to your letter.; There are no Federal Motor Vehicle Safety Standards applicable t plastic fuel tanks. Standard No. 301, which includes the fuel tank in the crash performance requirements of the vehicle, makes no reference to the construction or design details of the fuel tank. A booklet briefly describing the issued standards is enclosed.; The Department of Transportation does not routinely receive and tes fuel tanks of the various manufacturers, however, the Department keeps abreast of technical advancements of these companies through technical society meetings and trade journals. it has been brought to our attention that Dow Chemical Company has done considerable work with high density polyethylene fuel tanks and offers an internal treatment of these tanks which is claimed to reduce considerably the permeation of gasoline through the walls. Further information may be obtained from the following source:; >>>Dow Chemical U.S.A., Plastics Department, Midland, Michigan 48640<<< Standard No. 116 is applicable to Hydraulic Brake Fluids and i included in the consolidated edition of the Federal Motor Vehicle Safety Standards and Regulations, as per the enclosed order form.; The physical characteristics and labeling requirements of brake fluids including silicones, are included in this standard, a copy of which is enclosed for your information. Your inquiry concerning the use of silicones in automobiles can best be answered by the Original Equipment Manufacturers or the automotive companies. The interest of the Department in materials is primarily performance rather than design considerations, for example, an elastomeric material could be silicone, neoprene, or other elastomer, as long as the standards are complied with.; The Bureau of Motor Carrier Safety has issued standards that ar applicable to commercial vehicles engaged in interstate commerce, and some of those standards apply to fuel tanks. A portion of these regulations that pertains to fuel tanks is also enclosed for your information, along with an Advance Notice of Proposed Rule Making that concerns plastic fuel tanks (F.R., Vol. 36, No. 178, September 14, 1971). Additional information is available from the Bureau of Motor Carrier Safety, Federal Highway Administration, 400 Seventh Street, S.W., Washington D.C. 20590.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2579OpenMr. Paul Ideker, Lansdale, Carr & Baum, Advertising, Marketing & Management, 17622 Armstrong Avenue, Irvine, CA 92705; Mr. Paul Ideker Lansdale Carr & Baum Advertising Marketing & Management 17622 Armstrong Avenue Irvine CA 92705; Dear Mr. Ideker: This responds to your March 25, 1977, letter asking whether you proposed tire registration card to be used by your retail tire stores meets the requirements of 49 CFR Part 574, *Tire Identification and Recordkeeping*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approvals of compliance with agency standards or regulations. The agency will, however, give an informal opinion as to whether your registration card appears to satisfy the requirements of the regulation.; The proposed card that you submitted is similar to the exampl presented in Figure 3 of Part 574. Accordingly, it appears to comply with most of the requirements of that regulation. The actual seller of the tires, however, is not identified on the form. Since Part 574.7 requires that the tire seller be identifiable to the tire manufacturer, the form should disclose that information. Naming only the corporate office is insufficient, since that does not readily identify the store through which the tire was sold. The NHTSA suggests that the actual seller's name and address be provided on the card as shown on Figure 3.; It is our understanding that the tire seller will forward the cards t you who will then forward the information to the manufacturer. This process is acceptable to the NHTSA as long as the information is forwarded to the manufacturer within the time frame specified in Part 574.8.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4931OpenMr. Don Weidman Manager, Special Projects The Grote Manufacturing Company 2600 Lanier Drive Madison, Indiana 47250; Mr. Don Weidman Manager Special Projects The Grote Manufacturing Company 2600 Lanier Drive Madison Indiana 47250; Dear Mr. Weidman: This responds to your letter of November 25, 1991 with respect to the applicability of some new requirements of Motor Vehicle Safety Standard No. 108 to 'agricultural vehicles and implements when they are traveling on the highways.' Specifically you ask whether the requirements of Standard No. 108 or SAE J137 must be complied with when agricultural equipment is in use. The Federal motor vehicle safety standards apply to motor vehicles, which are defined, in pertinent part, by the National Traffic and Motor Vehicle Safety Act as vehicles 'manufactured primarily for use on the public streets, roads, and highways.' Because the primary use for agricultural vehicles such as farm tractors, combines, and the like is off the public roads, and their use of the public roads is incidental to their intended use, NHTSA does not consider agricultural vehicles to be 'motor vehicles' within the meaning of the Act. This means that they do not have to conform to Standard No. 108, or any other Federal motor vehicle safety standard. Regulations governing the use of the public roads are issued and enforced by the individual States. We have no knowledge whether any State requires the lighting on agricultural equipment to conform to SAE J137, or to Standard No. 108. The American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203, may be able to answer this question for you. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam4139OpenKarl-Heinz Faber, Vice President, Product Compliance and Service, Mercedes-Benz of North America, Inc., One Mercedes Drive, P.O. Box 350, Montvale, NJ 07645; Karl-Heinz Faber Vice President Product Compliance and Service Mercedes-Benz of North America Inc. One Mercedes Drive P.O. Box 350 Montvale NJ 07645; Dear Mr. Faber: This responds to your letter addressed to Mr. Barry Felrice concernin Federal Motor Vehicle Safety Standard No. 101, *Controls and Displays*, and use of the 'fanfare' symbol. According to your letter, all Mercedes-Benz passenger cars are provided with a horn that when activated produces an audible tone. The control for so activating the horn is located in the steering wheel hub. In addition to the standard horn, your company also offers an optional system on some models which permits the driver to choose either the standard tone or a higher frequency tone by means of a dash-board-mounted rocker switch. The rocker switch is identified by the fanfare symbol. The audible tone selected is then produced by activating the horn control in the steering wheel in the usual manner. This letter confirms that the use of the fanfare symbol for the rocker switch described above is permissible under Standard No. 101.; By way of background information, the National Highway Traffic Safet 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 vehicles and equipment meet applicable safety standards. The following represents our opinion based on the facts provided in your letter.; Standard No. 101 requires that vehicles with any control listed in th standard must meet specified requirements for the location, identification and illumination of such control. See section S5. Among the controls listed in Standard No. 101 is the 'horn' control. See section S5.1 and column 1 of Table 1.; It is our opinion that the 'horn' control referred to by Standard No 101 is limited to that which activates the horn to produce an audible tone. Thus, a separate rocker switch which permits the driver to choose different tones but does not activate the horn to produce an audible tone is not considered to be a 'horn' control within the meaning of Standard No. 101. Since a control of this type is not otherwise covered by Standard No. 101 or any other standard, the identification of the control is at the option of the manufacturer.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam5289OpenMs. Kathy Rose Account Directive FitzGerald Corporation 8341 Artesia Boulevard, Suite P Buena Park, CA 90621; Ms. Kathy Rose Account Directive FitzGerald Corporation 8341 Artesia Boulevard Suite P Buena Park CA 90621; Dear Ms. Rose: Your letter of October 12, 1993, to the Office of Moto Carriers in Sacramento, has reached us for reply. Your company produces a 'trailer skirting' for van trailers, and some of your customers have asked 'whether it is legal to have the retroreflective tape which is required by Motor Vehicle Safety Standard No. 108 to be applied to the length of the trailer be placed below the trailer, on the trailer skirting.' The letter does not indicate whether the skirting is intended as original or aftermarket equipment. If the skirting is original equipment that is added to the trailer at the time of its manufacture and intended to remain there for the life of the trailer, the conspicuity treatment required by the standard may be affixed to it, provided that it is mounted as near as practicable within a range that is not less than 375mm and not more than 1525mm (approximately 15 to 60 inches) above the road surface. Under that condition, the portion of the trailer side that is above the skirting need not be equipped with the conspicuity treatment. If the skirting is aftermarket equipment, there is no requirement or restriction relating to conspicuity treatment of the skirting. We assume that the trailer to which it will be attached, if manufactured on or after December 1, 1993, will bear conspicuity markings in accordance with the standard. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam1276OpenMr. E.J. Johnson, Administrator, Maryland Department of Transportation, Motor Vehicle Administration, 6601 Ritchie Highway, N.E., Glen Burnie, Maryland 21061; Mr. E.J. Johnson Administrator Maryland Department of Transportation Motor Vehicle Administration 6601 Ritchie Highway N.E. Glen Burnie Maryland 21061; Dear Mr. Johnson: This is in further response to correspondence dated JUly 10, 1973 between the Maryland Department of Transportation and Mr. Bernard Nolan. Mr. Nolan had written to the Maryland State Attorney General's Office regarding the practice of tire dealers of selling tires that have been relabeled 'tube type' by their manufacturer, while representing that it was not necessary, and may even be unsafe, to install tubes in them. You attach a memorandum to you from Mr. Thomas J. Widerman which concludes that the practice does not violate any Federal or State law but recommend that Maryland's proposed tire safety standard be amended to prohibit the practice. You indicate to Mr. Nolan that you are forwarding the matter to this agency for appropriate action.; We believe this practice involves at least a technical violation of th National Traffic and Motor Vehicle Safety Act. Section 108(a) (1) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S1397(a)(1)) prohibits, among other things,the sale of motor vehicle equipment manufactured after the effective date of an applicable safety standard that does not conform to the standard.; We believe a person who sells a 'tube type' tire as a tubeless tire i at least representing that the tire will meet the Federal standard applicable to tires, No. 109, without a tube. Accordingly, we believe that it is appropriate under the Safety Act to test that tire to the standard as a tubeless tire and, if failure occurs, to initiate civil penalty proceeding against the tire seller. That seller may also be liable for civil penalties for certifying the tire as conforming in a false and misleading manner (Sec 108(a) (3) of the Safety Act, 15 U.S.C. S 1397(a) (3)).; I am therefore referring the matter to our enforcement personnel wit the recommendation that they inquire into the matter.; However, I also concur with the recommendation of Mr. Widerman that specific prohibition against this practice be made part of Maryland law. NHTSA's enforcement procedures are civil in nature, and involve determinations that products fail to meet technical tests which are time consuming and costly to run. State criminal procedures would, in our view, be far more effective than NHTSA's procedures in dealing with situations such as this.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam0749OpenMr. John Forbes, Research Associate, Consumer Research Center, College of Business Administration, University of Puerto Rico, Rio Piedras, Puerto Rico 00931; Mr. John Forbes Research Associate Consumer Research Center College of Business Administration University of Puerto Rico Rio Piedras Puerto Rico 00931; Dear Mr. Forbes: This is in reply to your letter of June 9, 1972, raising certai questions concerning the National Traffic and Motor Vehicle Safety Act, and the Defect Reports regulations (49 CFR Part 573).; You ask whether the amendments made by sections 4(a) and (c) of Publi Law 91-265 took effect on November 28, 1970 or later. Section 4(d) of that law specified, as you note, that these sections take effect 180 days after the enactment of the Act, unless the Secretary of Transportation determined that a later date was in the public interest. No such determination was made, and the sections took effect 180 days after the Act's enactment. However, our computation shows that 180 days after May 22 is November 18, not November 28.; You ask if Owners Lists (49 CFR 573.6), including vehicl identification numbers, can be obtained by NHTSA and transmitted to your organization. The NHTSA would not consider it appropriate to require manufacturers to submit owner's (sic) lists to it for purposes not involved in the enforcement of the National Traffic and Motor Vehicle Safety Act. We would not consider the study you wish to perform to be within this purpose.; You also ask if we can furnish you copies of Quarterly Reports (49 CF 573.5) at least as they relate to cars sold in Puerto Rico. Quarterly reports submitted by manufacturers, except for the production figures submitted pursuant to section 573.5(b), are considered to be public documents and are available for public inspection. Due to the large number of reports we receive, however, we can furnish copies only if the precise reports desired are specified. The reports do not disclose the geographical location of the vehicles involved.; With reference to your request for the latest version of the leaflet 'Motor Vehicle Safety Defect Recall Campaigns,' I have enclosed the volume which provides information for the complete year 1971, and a new volume dealing with January-March 1972.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam2266OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to Blue Bird Body Company's February 13, 1976, questio whether 47 described intersections of bus body components qualify as 'body panel joints' subject to the requirements of Standard No. 221, *School Bus Body Joint Strength*. You also ask what test procedures are used in testing joints if the means described in S6.1.1 or S6.1.2 cannot be employed due to the configurations of the intersecting components.; The terms which establish the applicability of the requirements of th standard to a particular section of a school bus body are defined in S4 of the standard. Read together, they establish the following test. If the edge of a surface component (made of homogeneous material) in a bus that encloses the bus' occupant space comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose or is a door, window, or maintenance access panel. Applying this test to the 47 intersections of bus body components you describe, it appears that the areas corresponding to the following numbered paragraphs of your letter are bus body joints and therefore must meet the 60-percent joint strength requirements: 1, 4, 5, 6, 7, 8, 9, 11, 13, 14, 15, 19, 20, 23, 26, 28, 29, 50.; The front and rear headers described in paragraphs 2 and 12 ar considered primarily structural and have only an incidental role in enclosing the occupant space and, therefore, are not considered 'body panels' for purposes of the requirements.; The wire molding discussed in paragraphs 3 and 10 is considered maintenance access panel, excluded from the requirements only if a wire is installed behind the molding.; The bumper trim strip described in paragraph 17 is not considered t have a function in enclosing the occupant space and is therefore not considered a body component for purposes of the requirements.; Your assumption that components located entirely below the level of th floor line are not subject to the standard is correct. However, body panels that do 'enclose bus' occupant space' because a portion lies above the floor line are subject to the requirements. Thus, the rear center skirt described in paragraph 16, the bumper trim panel described in paragraph 18, and the auxiliary cross members described in paragraph 21 are not subject to the requirements.; The rubrails described in paragraphs 22, 23, 27, 28, and 29 are no themselves considered to have a function in enclosing the occupant space and therefore are not considered body components for purposes of the requirements. For purposes of testing the complex joints to which they are fastened, they should be modified as necessary to prevent them from affecting testing of the underlying joint.; The wheelhousing trim described in paragraph 24 is not considered t have a function in enclosing the occupant space and is therefore not considered a body component for purposes of the requirements.; Because the plywood described in paragraph 25 is attached to a floo panel and is only added to some buses for insulation purposes, it is not considered to have a function in enclosing the occupant space and is therefore not considered a body component for purposes of the requirements.; The extruded aluminum trim described in paragraph 30 is not considere to have a function in enclosing the occupant space and is therefore not considered a body component for purposes of the requirements.; The NHTSA agrees that paragraphs 30 through 36 and 38 through 4 describe joints between maintenance access panels and the bus body. The ventilation duct in paragraph 37 is the type of ventilation space that is not subject to requirements for joint strength.; In many of your requests for clarification, you asked what means woul be employed to test joints in which the two body components in question are not flat surfaces in the same or parallel planes. The NHTSA intends to test joints that are not capable of being tested as specified in S6.1.1 or S6.1.2 by determining the nature of the two body components and testing identical materials joined by the same means as is used by the school bus manufacturer. The materials will be flat and conform to the dimensions described in Figure 1, and they will be oriented in the same fashion as described in Figure 1. For example, the 90-degree angle at the joint described in paragraph 20 is ignored for purposes of the NHTSA test procedure by simulating the joint and using opposing forces in the same or parallel planes. In this way, the agency can examine a manufacturer's technique to see if the fastening method constitutes the exercise of due care in complying with the joint strength requirement.; You also asked what procedure would be used in testing joints wher more than two panels or body components are joined by one fastener (example in paragraph 29). In these cases, the definition of 'body panel joint' in S4 describes several joints, involving one at each intersection area that qualifies as joint. For each pair of components, the tensile strength of the weaker panel is determined, and the joint is required to sustain a load of not less than 60 percent of that tensile strength. For example, in the case of two side panels riveted to a bow, one joint would be between the two lapped panels and 60 percent of the weaker panel would be the test requirement. At the same time, a separate test of the joint between the bow and the panel that contacts the bow would be required, with 60 percent of the weaker component's tensile strength established as the level of strength for testing.; I trust that this discussion will permit a determination of wha portions of your products are subject to the requirements of Standard No. 221 and what test procedures are employed in satisfaction of the requirements.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1784OpenMr. Richard L. Hoover, Executive Vice President, Flash-Patrol Safety Equip. Pro., P.O. Box 194, Chenoa, Illinois 61726; Mr. Richard L. Hoover Executive Vice President Flash-Patrol Safety Equip. Pro. P.O. Box 194 Chenoa Illinois 61726; Dear Mr. Hoover: This is in response to your letter of January 17, 1975, asking whethe your 'STASH-FLASH' barricade is permissible for emergency and other use.; The National Highway Traffic Safety Administration neither approved no disapproved individual devices. Rather, we establish performance standards for special types of motor vehicle equipment. As Federal Motor Vehicle Safety Standard 125, dealing with warning devices, does not apply to devices with self-contained energy sources, your device would not fall under the requirements of that standard, and may be produced by you without regard to the safety standards.; I trust this information is useful to you. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2290OpenMr. John Eckhold, Automotive Safety Director, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. John Eckhold Automotive Safety Director Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold: I am writing to inform you that the National Highway Traffic Safet Administration (NHTSA) will, for a limited time, refrain from enforcing one portion of 49 CFR Part 575, *Consumer Information Regulations*.; Subpart B of Part 575 specifies certain items of consumer informatio that apply to motor vehicles and their tires. Section 575.6 in Subpart A requires this information to be delivered to first purchasers (paragraphs (a) and (b)), made available to prospective purchasers (paragraph (c)) and submitted to the NHTSA (paragraph (d)). In particular, S 575.6(d) requires that:; >>>Each manufacturer of motor vehicles...shall submit to th Administrator 10 copies of the information specified in Part B of this part that is applicable to the vehicles or tires offered for sale, at least 30 days before that information is first provided for examination by prospective purchasers pursuant to paragraph (c) of this section.<<<; I understand that the strike by the United Rubber Workers has, b cutting off the supply of new tires, created an emergency situation within the motor vehicle industry, making it difficult for a manufacturer to know more than several days before it completes a vehicle which tires will be available for installation on the vehicle. I understand further that the provision of such information to the NHTSA 30 days before it is made available to prospective purchasers has become virtually impossible.; In view of the impracticability under the current circumstances of th 30-day-notice requirement, the NHTSA has concluded that enforcement of the requirement at this time is inappropriate. Accordingly, with respect to vehicles offered for sale during the strike and the 60-day period following its settlement, the NHTSA will refrain from enforcing the 30-day-notice requirement in S 575.6(d). Submittals of information to the agency must continue to be made, however, not later than the time the information is made available to prospective purchasers. With respect to vehicles that will be offered for sale at the expiration of the 60-day period, the NHTSA expects to begin receiving submittals after the thirtieth day following settlement of the strike.; Please note that the requirements of paragraphs (a), (b), and (c) of 575.6, as well as Federal Motor Vehicle Safety Standard No. 110, *Tire Selection and Rims--Passenger Cars*, are not affected by this letter.; Sincerely, James B. Gregory, Administrator |
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.