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: aiam2376OpenMr. Paul Atkinson, No. 13 Connell Dr., Little Rock, AR 72205; Mr. Paul Atkinson No. 13 Connell Dr. Little Rock AR 72205; Dear Mr. Atkinson: This is in response to your June 18, 1976, letter concerning th application of Federal Motor Vehicle Safety Standard No. 117, *Retreaded Pneumatic Tires*, to passenger car tires that are retreaded from bead to bead.; I understand that in this process, the labeling information molded o the sidewalls of the tire to be retreaded is buffed off prior to the application of new rubber. You have requested our assurance that 'it is permissible to do bead to bead retreading, removing the present labeling and remolding all the pertinent information on the tire.'; The requirements for casings to be used in retreading are set out i S5.2.3 of Standard No. 117:; >>>Each retreaded tire shall be manufactured with a casing that bears permanently molded at the time of its original manufacture into or onto the tire sidewall, each of the following:; (a) The symbol DOT, (b) The size of the tire, and (c) The actual number of plies or ply rating.<<< This section requires the above information to be present on the casin at the beginning of the retreading process, to ensure both that the carcass was originally manufactured to comply with Standard No. 109, *New Pneumatic Tires--Passenger Cars*, and that the retreader has reliable information on which to base the labeling of the completed tire. The section does not, however, require that this originally molded information be retained on the completed tire.; Certification and labeling requirements for completed retreaded tire are set out in S6 of the standard. The DOT symbol required by S6.1, however, is not a 'remolding' of the original DOT symbol (certifying compliance with Standard No. 109) that may have been buffed off. It is a new certification by the retreading party that his product complies with Standard No. 117. Further, this new DOT symbol must be followed by the letter 'R', as indicated in 49 CFR S 574.5, *Tire Identification and Recordkeeping*. 'Remolding' of the original DOT symbol is neither required nor permitted. Finally, the information required by S6.3 to appear on the completed tire is permitted, but not required, to so appear through retention of the original labeling.; In conclusion, bead- to-bead retreading is not prohibited by Standar No. 117, provided that the casings satisfy S5.2.3 at the beginning of the retreading process, and all other requirements of the standard are met.; Yours truly, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3784OpenMr. William K. Sweeney, Assistant General Counsel, Grumman Corporation, 445 Broad Hollow Road, Melville, NY 11747; Mr. William K. Sweeney Assistant General Counsel Grumman Corporation 445 Broad Hollow Road Melville NY 11747; Dear Mr. Sweeney: This responds to your letter of November 22, 1983, regarding th application of Safety Standard No. 208 (49 CFR 571.208) to the new Kubvan minivan you intend to manufacture and distribute. You state in your letter that the Kubvan is a minivan designed primarily for delivery and utility service. You ask whether the Kubvan must be equipped with a lap and shoulder belt protection under S4.2.2.2 of the standard.; You state that Grumman Olson has built both left hand and right han drive models of the Kubvan. The right hand drive models are intended for use by the United States Postal Service (USPS). You add that Grumman Olson also plans to sell right hand vehicles to any and all interested customers.; Section 4.2.2.2 requires trucks with a GVWR of 10,000 pounds or less t provide a lap and shoulder belt protection system, except for those 'vehicles designed to be exclusively sold to the United States Postal Service.' As correctly stated in your letter, all Kubvans sold to customers other than the USPS must be equipped with a lap and shoulder belt assembly. However, based on the intent of S4.2.2.2 and the unique operating needs of the USPS, right hand Kubvans sold to the USPS need only be equipped with a lap belt system.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5346OpenKen Simons, Esq. P.O. Box 883 Fairmont, WV 26555; Ken Simons Esq. P.O. Box 883 Fairmont WV 26555; "Dear Mr. Simons: This responds to your letter asking about brak requirements for trailers used in tractor trailer combinations. I apologize for the delay in our response. You asked whether all such trailers are required to be equipped with 'maxi' brakes on one or both axles. You state that a 'maxi' brake is found on all road tractors and 'sets the brakes automatically when the air pressure gets down to a minimum level.' Please note that the term 'maxi' brakes ordinarily refers to spring brakes used in parking and emergency brake applications. I further note that most, but not all, trailers are equipped with spring brakes. I am pleased to have this opportunity to explain our requirements. By way of background information, under the National Traffic and Motor Vehicle Safety Act ('Safety Act,' 15 U.S.C. 1392), the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA does not approve vehicles or equipment. Instead, manufacturers are required to certify that their vehicles or equipment meet all applicable standards. Standard No. 121, Air Brake Systems (49 CFR 571.121, copy enclosed), specifies performance requirements for trucks, buses and trailers equipped with air brake systems. The purpose of the standard is to insure safe braking performance of vehicles under normal and emergency conditions. While Standard No. 121 does not require manufacturers to use spring brakes or any other particular type of brake system, many manufacturers use spring brakes to comply with the standard's requirements concerning parking brake performance (trucks, buses and trailers, see S5.6), emergency brake performance (trucks and buses only, see S5.7), and trailer pneumatic system failure performance (see S5.8). I note that while the requirements of S5.6 and S5.8 apply to most air-braked trailers, S3 of Standard No. 121 excludes some trailers from all of the standard's requirements. In addition, S5.6 and S5.8 specify alternative requirements for some trailers. 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 Enclosures"; |
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ID: aiam5324OpenMr. Ulrich Metz Automotive Division Robert Bosch GmbH K4/ERW3 Postfach 1163 77813 Buel Germany; Mr. Ulrich Metz Automotive Division Robert Bosch GmbH K4/ERW3 Postfach 1163 77813 Buel Germany; "Dear Mr. Metz: This responds to your letter to this agency regarding new windshield wiper system you intend to develop for front windshields. I apologize for the delay in responding. The drawing you enclosed with your letter shows a wiper system consisting of one wiper arm and blade, as distinguished from the conventional systems consisting of two wiper arms and blades. Your wiper system takes different paths on the forward and the return strokes of the wiper cycle. Thus, as you stated in your letter, 'the vision areas are fulfilled only in the sum of forward and return movement.' You asked whether that is permissible under Federal Motor Vehicle Safety Standard (FMVSS) No. 104, Windshield Wiping and Washing Systems (copy enclosed), and if so, whether the minimum frequencies specified by FMVSS 104 apply to this wiper system. As explained below, the answer to both questions is yes. The essential feature of a windshield wiper system, from a safety standpoint, is its ability to clear a specific portion of the windshield. The number of wipers necessary to provide the driver with a sufficient field of view is not specified in FMVSS 104. Therefore, the number of wipers is immaterial so long as the minimum percentages of critical areas are cleared. The areas to be wiped are specified in paragraphs S4.1.2 and S4.1.2.1 of the standard. S4.1.2 establishes three windshield areas for passenger car windshields, designated as areas 'A', 'B', and 'C.' Each area is required to have a certain percentage of the glazing area wiped as shown in Figures 1 and 2 of SAE Recommended Practice J903a, May 1966 (copy enclosed), using the angles specified in Tables I, II, III, and IV of FMVSS 104, as applicable. Those tables apply to passenger cars of varying overall widths, namely, from less than 60 inches to more than 68 inches. The angles set forth in the tables vary according to the overall width of the vehicle. Finally, paragraph S4.1.2 provides that the percentage of each area required to be cleared must also be within the area bounded by a perimeter line on the glazing surface one inch from the edge of the daylight opening. With that background in mind, I will address your first question. FMVSS 104 does not specify whether the wiper needs to clear a windshield on either or both strokes. SAE Recommended Practice J903a, at paragraph 2.5, however, defines an effective wipe pattern as 'that portion of the windshield glazing surface which is cleaned when the wiper blade travels through a cycle) (emphasis added). A 'cycle' is defined in paragraph 2.14 of SAE Recommended Practice J903a as consisting of 'wiper blade movement during system operation from one extreme of the windshield wipe pattern to the other extreme and return' (emphasis added). It is NHTSA's opinion, therefore, that so long as the required windshield area is cleared by your wiper in a complete cycle, the requirements of paragraphs S4.1.2 and S4.1.2.1, FMVSS 104, have been met. As indicated above, your wiper system must comply with the minimum frequencies specified in section S4.1.1, Frequency, of FMVSS 104. That section requires that each windshield wiping system must have at least two frequencies or speeds. One must be at least 45 cycles per minute (cpm), regardless of engine load and speed. The other must be at least 20 cpm, also regardless of engine load and speed. In addition, the difference between the higher and lower speeds must be at least 15 cpm, regardless of engine load and speed. There are no exceptions to these frequency requirements, regardless of the number or design of the wiper arms comprising the system. Your letter did not indicate whether your wiper system is designed to be used on passenger cars or motor vehicles other than passenger cars, or both. Please note that section S2 of FMVSS 104, Application, provides that the standard applies to multipurpose passenger vehicles, trucks, and buses in addition to passenger cars. All those vehicles are required to have power-driven windshield wiping systems that meet the frequency requirements of section S4.1.1. The wiped area requirements of S4.1.2, however, apply only to passenger cars. I hope this information will be helpful to you. Should you have any further questions or need any additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures"; |
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ID: aiam2370OpenMr. Kenneth R. Thompson, Jr., Vice President, Modular Ambulance Corp., 1801 So. Great Southwest Parkway, Grand Prairie, TX 75057; Mr. Kenneth R. Thompson Jr. Vice President Modular Ambulance Corp. 1801 So. Great Southwest Parkway Grand Prairie TX 75057; Dear Mr. Thompson: We have received your letter of July 26, 1976, petitioning for temporary exemption from Motor Vehicle Safety Standard No. 301-75. When you forward the financial statements promised we shall prepare a notice for the *Federal Register*.; I would like to comment on two aspects of your petition. The first i that in our opinion, each manufacturer supplying you with a chassis is an 'incomplete vehicle' manufacturer as defined by 49 CFR Part 568, and should be able to provide you with sufficient information, in the incomplete vehicle document accompanying each chassis, to enable you to insure that your ambulances upon completion conform with Standard No. 301-75. I enclose a copy of a recent letter that we sent General Motors expressing our view on this subject. Since your problem is basically similar, as part of your good faith efforts to meet Standard No. 301-75 you should attempt to obtain compliance information from your chassis manufacturers as soon as you can. We would like to be informed if you are unable to obtain this information.; My second comment is that your petition presents the 'worst case approach, based upon the presumed necessity to crash test each of the 11 models you manufacture. As a matter of clarification, there is no legal requirement that a manufacturer conduct a barrier test before he certifies compliance with Standard No. 301-75. He must, however, have a reasonable basis for certification that the vehicle, if barrier tested, would meet Standard No. 301-75. Many manufacturers prefer the assurance that is provided by testing according to a standard's procedure. However, engineering calculations, computer simulations, etc., can often provide a reasonable basis for certification. You may wish to reevaluate your petition's cost estimates in light of this.; Yours truly, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4497OpenMr. James P. Nolan, Jr. President Nolan and Taylor-Howe Funeral Home, Inc. 5 Laurel Avenue Northport, NY 11768; Mr. James P. Nolan Jr. President Nolan and Taylor-Howe Funeral Home Inc. 5 Laurel Avenue Northport NY 11768; "Dear Mr. Nolan: This is in reply to your letter of March 24, 1988 enclosing a letter you have received from the Department of Motor Vehicles, New York State, advising you that your l987 Cadillac hearse requires a center high-mounted stop lamp. You have asked for the specifications of such a lamp. The center high-mounted stop lamp is required only on passenger cars. A passenger car is defined as a motor vehicle 'designed for carrying l0 persons or less.' A 'multipurpose passenger vehicle' is one 'designed for carrying l0 persons or less which is constructed either on a truck chassis or with special features for occasional off road operation.' A 'truck' is defined as a motor vehicle 'designed primarily for the transportation of property or special purpose equipment.' The agency recognizes chassis constructed for commercial use, such as a hearse, as the equivalent of a truck chassis. The determination of vehicle category is initially that of the manufacturer or final stage assembler who certifies compliance with all Federal motor vehicle safety standards applicable to the category of vehicle selected. In our opinion, a hearse could be properly certified as a either a 'multipurpose passenger vehicle,' or a 'truck.' In a conversation with Taylor Vinson of this Office on April 29, you informed us that the first six characters of the VIN of your hearse are 'lGED09', and that its final stage assembler, Superior, had certified it as an 'MPV' (multipurpose passenger vehicle). The 'G' in the VIN identifies it, according to internal documents of the initial stage manufacturer, General Motors, as 'Cadillac Incomplete Coaches' (meaning, it would appear, funeral coaches), and the '9' as 'Cadillac Commercial Body/Chassis.' This chassis does not form the basis of any passenger car completed by Cadillac. The letter from New York State states 'The manufacturer claims that funeral cars are classified as multipurpose vehicles and do not require the lights.' This is correct, as you have told us that Superior has classified it as an MPV, and certified its compliance to all standards applicable to that vehicle category. As the center high-mounted stop lamp standard is not one of those applicable to multipurpose passenger vehicles, there is no Federal requirement that your hearse be equipped with such a lamp. We appreciate your interest in safety, and trust that this answers your question. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3195OpenMr. Brian Gill, Manager, Certification Department, American Honda Motor Co., Inc., P.O. Box 50, 100 W. Alondra Boulevard, Gardena, California 90247; Mr. Brian Gill Manager Certification Department American Honda Motor Co. Inc. P.O. Box 50 100 W. Alondra Boulevard Gardena California 90247; Dear Mr. Gill: This is in response to your letter of November 18, 1979, requesting a interpretation as to whether the VIN plate samples you enclosed with your letter comply with the requirements of Standard No. 115, *Vehicle identification number*.; You enclosed two proposed VIN plates in your letter, one fo automobiles and one for motorcycles.The VIN plates themselves and the pre-printed lettering which appears on them seem to conform to the requirement of Standard No. 115. The lettering is clear and indelible, as required by S4.3, in that it cannot be removed without damage to the surface on which it is printed. Further, the plate when riveted to the vehicle would be considered to be permanently affixed in that it cannot be removed without damage (S4.3). The type face utilized for the lettering consists of capital, sans serif characters with a minimum height of 4 mm as required by S4.3.1.; The letters stamped on the automobile VIN plate 'SL5322AS000001', ca hardly be seen, and would not appear to meet the requirements of S4.3 and S4.4.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2002OpenMr. Russell O. Lightcap, Chief, Office of Equipment, Department of Transportation, P.O. Box 9067, Sacramento, CA 95816; Mr. Russell O. Lightcap Chief Office of Equipment Department of Transportation P.O. Box 9067 Sacramento CA 95816; Dear Mr. Lightcap: This responds to your letter of June 12, 1975, requesting confirmatio that you as a final-stage manufacturer would only have to check the application and release times of a truck whose chassis you shortened or lengthened in order to certify that vehicle to the requirements of Federal motor vehicle safety standard (FMVSS) No. 121, *Air Brake Systems*.; Certification of vehicles to the standard is an area which ou statutory scheme leaves to the manufacturers, and in which, aside from discussion of general principles, the agency has declined to issue statements of approval.; The National Highway Traffic Safety Administration has stated tha actual road tests by final stage manufacturers are not necessary to establish compliance with Standard No. 121 or other standards, where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. The agency has recognized that small organizations cannot be expected to test to the same scale or by the same methods as the large integrated automotive manufacturers. Supplier warranties and instructions are one of the primary means by which smaller assemblers are expected to use statutory 'due care' to see that their products conform.; From this discussion it should be apparent that verifying only th brake actuation and release functions will probably be an insufficient basis for certifying that the vehicle will comply, for example, with the stopping distance requirements of the standard. Engineering calculations may, however, satisfy you, in the exercise of due care, that the vehicle as modified meets all the requirements of the standard.; The incomplete vehicle documentation provided with the vehicle woul generally serve as the basis of certification to equipment requirements, to the degree that the equipment is undisturbed. The addition of an axle may cause the air reservoirs to no longer satisfy the air volume requirements of the standard.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2000OpenMr. Russell O. Lightcap, Chief, Office of Equipment, Department of Transportation, P.O. Box 9067, Sacramento, CA 95816; Mr. Russell O. Lightcap Chief Office of Equipment Department of Transportation P.O. Box 9067 Sacramento CA 95816; Dear Mr. Lightcap: This responds to your letter of June 12, 1975, requesting confirmatio that you as a final-stage manufacturer would only have to check the application and release times of a truck whose chassis you shortened or lengthened in order to certify that vehicle to the requirements of Federal motor vehicle safety standard (FMVSS) No. 121, *Air Brake Systems*.; Certification of vehicles to the standard is an area which ou statutory scheme leaves to the manufacturers, and in which, aside from discussion of general principles, the agency has declined to issue statements of approval.; The National Highway Traffic Safety Administration has stated tha actual road tests by final stage manufacturers are not necessary to establish compliance with Standard No. 121 or other standards, where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. The agency has recognized that small organizations cannot be expected to test to the same scale or by the same methods as the large integrated automotive manufacturers. Supplier warranties and instructions are one of the primary means by which smaller assemblers are expected to use statutory 'due care' to see that their products conform.; From this discussion it should be apparent that verifying only th brake actuation and release functions will probably be an insufficient basis for certifying that the vehicle will comply, for example, with the stopping distance requirements of the standard. Engineering calculations may, however, satisfy you, in the exercise of due care, that the vehicle as modified meets all the requirements of the standard.; The incomplete vehicle documentation provided with the vehicle woul generally serve as the basis of certification to equipment requirements, to the degree that the equipment is undisturbed. The addition of an axle may cause the air reservoirs to no longer satisfy the air volume requirements of the standard.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam4758OpenMr. Charles T. Thomas Prestige Travel 10333 Richmond Avenue, Suite 170 Houston, Texas 77042; Mr. Charles T. Thomas Prestige Travel 10333 Richmond Avenue Suite 170 Houston Texas 77042; "Dear Mr. Thomas: This is in reply to your recent undated letter askin for a waiver of one of the requirements of 49 CFR 591.5(g) for persons working outside the United States and seeking to import a nonconforming vehicle, i.e., the requirement that 'the importer's assigned place of employment has been outside the United States at all times between October 31, l988, and the date the vehicle is entered into the United States.' You are able to meet the other requirements of paragraph (g), but you returned to the United States in September l988 after a 12-year employment abroad, and your l985 Jaguar remains in Germany. We are sorry that we are unable to provide the waiver you seek. This specific requirement was established by Congress as part of an exception to more rigorous requirements that became effective on, and applicable to, vehicles imported on and after January 31, l990, of this year. Further, Congress did not provide us with any authority to waive this requirement. These provisions were added to the National Traffic and Motor Vehicle Safety Act by the Imported Vehicle Safety Compliance Act of 1988, Public Law 100-562. However, our inability to waive this requirement does not mean that you will be unable to import your car. Under its new authority, the agency has tentatively determined that l985 Jaguar automobiles are eligible for importation (as well as a number of other cars). Public comments on the tentative determinations were due in mid-May. After a final determination is made, and assuming that it is favorable, you may then import your Jaguar pursuant to the requirements of 49 CFR 591.5(f). In other words, you may import the vehicle either through an importer registered with this agency as one who will certify compliance of the Jaguar with Federal safety standards, or by yourself upon demonstration that you have a contract with a registered importer. I enclose a copy of Part 591 for your information, as well as a list of registered importers approved as of April 13. We anticipate a final determination on vehicle eligibility this summer. If you wish to inquire as to the status of the determination, or to obtain an updated list of registered importers, please address your further correspondence to Director, Office of Vehicle Safety Compliance, National Highway Traffic Safety Administration, Washington, D.C. 20590. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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.