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: aiam3027OpenMr. Troy Martin, Chief of Specifications, State Board of Control, 111 East 17th Street, Austin, TX 78711; Mr. Troy Martin Chief of Specifications State Board of Control 111 East 17th Street Austin TX 78711; Dear Mr. Martin: This confirms your May 23, 1979, conversation with Roger Tilton of m staff in which you asked whether it is permissible for vehicles to be modified by the addition of propane gas systems replacing their regular fuel systems.; As Mr. Tilton stated, the National Highway Traffic Safet Administration permits the type of modification mentioned above. If the modification is done to a new vehicle, the person making the modification would be required to attach an alterer's label in accordance with Part 567.7, *Certification*, of our regulations. That label states that the vehicle, *as altered*, continues to comply with all safety standards. The standard that may be affected by such a modification would be Standard No. 301, *Fuel System Integrity*. If used vehicles are being modified, the person modifying the vehicle would not be required to attach a label. However, that person would be responsible for noncompliance with safety standards if he or she knowingly rendered inoperative any element of design installed in or on the vehicle in compliance with a safety standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4832OpenMr. Billy S. Peterson President Automotive Safety Testing, Inc. at TRC of Ohio, Bldg. 20 Rd. 152 & SR 33 East Liberty, OH 43319; Mr. Billy S. Peterson President Automotive Safety Testing Inc. at TRC of Ohio Bldg. 20 Rd. 152 & SR 33 East Liberty OH 43319; Dear Mr. Peterson: This is in reply to your letter of February 7, l99l to the Office of Chief Counsel asking for a clarification of allowable mounting locations and photometric output requirements for tail/stop lamps on passenger cars. One of your clients wishes to mount 'two-part' stop/tail lamps 'so that one lamp is mounted on the fixed quarter panel and a duplicate lamp is mounted on the trunk lid.' Each part of the two-part lamp is a combination tail/stop lamp. You have asked whether the minimum photometric requirements must be met by 'the lamp mounted to the quarter panel or may the portion mounted on the trunk lid count toward the photometric requirements.' Your 'two-part lamp' would be treated as two separate lamps. For purposes of compliance, only one of these two adjacent lamps must be designed to conform to Standard No. 108, and this conformance must be independent of any 'contribution' by the adjacent lamp. Although Standard No. 108 permits either the deck or the body mounted lamp to be the complying lamp, it would be our preference that the body mounted lamp be the one that complies, so that the benefit of a conforming stop/tail lamp would be realized during those occasions when the lid may be raised. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0522OpenMr. T. E. Needham, Engineering Department, Mechanisms Division, Amington Road, Birmingham B25 8EW, England; Mr. T. E. Needham Engineering Department Mechanisms Division Amington Road Birmingham B25 8EW England; Dear Mr. Needham: Your letter of November 4, 1971, concerning the compliance of two dua rear door locking systems with Standard 206, has been forwarded to this office for reply.; Both systems consist of >>>'. . . a primary locking system which when engaged renders th outside rear door handle and the inside rear door handle inoperative and a special locking device accessible from the door shut face, which when engaged renders the inside door handle inoperative but does not affect the outside door handle.'<<<; The systems differ in that engagement of the special locking device i the first system prevents the engagement of the primary locking system, while engagement of the special device in the second system does not have this effect.; As stated in the preamble to the April 27, 1968 amendment (33 F.R 6465) to the standard, S4.1.3 does not preclude the installation of a special locking mechanism in addition to the required locking mechanism. However, the required locking mechanism must be engageable or disengageable regardless of whether any additional locking mechanism is engaged or disengaged. If the special locking mechanism does not interfere with the operation of the required locking mechanism, it will not constitute a failure to comply with the standard.; Under these criteria, the first dual system would not comply with th standard since engagement of the special locking mechanism would interfere with the operation of the primary locking mechanism.; The second dual system would comply if engagement of the specia locking mechanism would prevent neither the engagement nor the disengagement of the primary locking mechanism.; Please write if I can be of any further assistance. Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0488OpenMr. Paul Wilson, Truck Trailer Manufacturers' Association; Mr. Paul Wilson Truck Trailer Manufacturers' Association; Telephone call from TTMA re GVWR This is a memorandum of a telephone conversation that I had with Mr Paul Wilson of the Truck Trailer Manufacturers' Association on November 19, 1971.; Mr. Wilson asked how the GAWR and GVWR requirements of the ne Certification regulations would apply to semitrailers with sliding rear axle bogies (sic). He said that he saw a danger that if the GVWR of a semitrailer were based on the load that could be carried with the rear axle in the rearmost position (the maximum load condition if the rear axle is the limiting factor), there was a possibility that the user would overload the axle by loading to that capacity with the axle in a more forward position. Conversely, if the GVWR were stated at a lower figure based on the axle in the forwardmost position, the actual capacity of the trailer would be understated.; I told Mr. Wilson that, with or without the new regulations, th situation obviously required the furnishing of specific instructions to the truck users, beyond any figures for GVWR and GAWR. The NHTSA, I said, did not restrict the furnishing of this information, either by label or in printed manual form, except that extraneous material should not be placed in the midst of the required information on the label. I also said that the GVWR could be lower than the sum of the axle ratings and the capacity at the kingpin.; Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5370OpenMr. James Schaub Midas Muffler Shop 180 Gause Blvd. Slidell, LA 70458; Mr. James Schaub Midas Muffler Shop 180 Gause Blvd. Slidell LA 70458; "Dear Mr. Schaub: This responds to your letter asking us about Federa Motor Vehicle Safety Standard No. 105 with regard to replacing brake rotors and/or drums. I apologize for the delay in our response. You stated that local automobile dealership service departments do not follow manufacturers' recommendations in this area, causing your customers to believe that your shop is fraudulently selling and installing parts on vehicles when they are not needed. You requested an interpretation of Standard No. 105 in this regard, and asked whether there is any basis for fraud in replacing rotors and drums when they are outside manufacturer safety tolerances. You stated that if you can present an established standard to your customers, you can prevent them from believing they have been taken advantage of. By way of background information, the National Traffic and Motor Safety Act (Safety Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards for new motor vehicles and new motor vehicle equipment. Standard No. 105, Hydraulic Brake Systems, specifies requirements for hydraulic brake systems and associated parking brake systems. The standard applies to new motor vehicles. While you asked for an interpretation of Standard No. 105, that standard is of little relevance to your situation. This is because the Federal motor vehicle safety standards do not apply to a motor vehicle after its first sale to a consumer. The Safety Act does include some provisions which are relevant to used vehicles. In particular, the Safety Act prohibits manufacturers, distributors, dealers, and motor vehicle repair businesses from knowingly rendering inoperative any safety device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a safety standard. However, this provision would ordinarily not be relevant to a decision whether to replace, or mill or turn, worn brake drums and rotors. With respect to your desire to show your customers an established standard in this area, I can call your attention to NHTSA's vehicle in use inspection standards. These standards set forth criteria for, among other things, inspecting service brake systems. You should be aware that these standards were developed for use by the States in establishing their inspection requirements. Thus, the standards only apply to the extent that they are adopted by individual States. I have enclosed a copy of the standards for your information and particularly call your attention to section 570.5(f). That section, which applies to vehicles with a GVWR of 10,000 pounds or less, reads as follows: (f) Disc and drum condition. If the drum is embossed with a maximum safe diameter dimension or the rotor is embossed with a minimum safety thickness dimension, the drum or disc shall be within the appropriate specifications. . . . This section reflects the importance NHTSA places on following manufacturer recommendations in this area. The states may regulate the repair of motor vehicles. We suggest that you investigate the laws of Louisiana to see whether they affect your situation. We cannot advise you about Federal or state requirements concerning fraud. You may wish to contact the Federal Trade Commission, your state government, and/or a private attorney about this matter. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0172OpenMr. Alan Masek, General Manager, Kawasaki Motors Corporation, 1062 McGaw Avenue, Santa Ana, CA 92705; Mr. Alan Masek General Manager Kawasaki Motors Corporation 1062 McGaw Avenue Santa Ana CA 92705; Dear Mr. Masek: This is in reference to your letter of July 28, 1969, in which yo inquire whether a company that imports motorcycles, performing final assembly in regard to such items as fuel tanks and fenders, may designate itself as the manufacturer for the purpose of the certification regulations, 49 CFR Part 367.; You state in your letter that Kawasaki Heavy Industries, Ltd., th primary fabricator of the motorcycles, assembles the engine and basic frame, wheel and brake assemblies, handlebars, seat, and 'some front lighting equipment'. The purpose of the manufacturer's designation in the certification regulations is to identify the company that has primary technical responsibility for conformity of the design and quality control of the assembly. It is our opinion, on the basis of the facts presented in your letter, that Kawasaki Heavy Industries, Ltd. is the manufacturer of the motorcycles in question within the meaning of the National Traffic and Motor vehicle Safety Act and the certification regulations.; You should note, however, that the certification and import regulation do not require that Kawasaki affix the label to the vehicles. The import regulations allow importation of uncertified vehicles in certain cases. such as those where the importer declares that he will bring them into conformity. 19 CFR S. 12.80(b)(2)(iii) and (iv). In regard to such cases, section 367.2(b) of the certification regulations states:; >>>'In the case of imported motor vehicles, the requirement of affixin a label or tag applies to importers of vehicles, admitted to the United States under S. 12.80(b)(2) of the joint regulations for importation of motor vehicles and equipment (19 CFR 12.80(b)(2)), to which the required label or tag is not affixed.'<<<; Section 367.4(g)(1) requires in such a case that the label affixed b the importer bear both the name of the manufacturer (Kawasaki) and the importer (McCormack). thus, the net result is that the label affixed by McCormack must bear the name of Kawasaki above that of McCormack. Alternatively, Kawasaki could affix the label prior to importation, naming only itself as the manufacturer.; We are pleased to be of assistance. Sincerely, Dowell H. Anders, Acting Chief Counsel |
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ID: aiam4998OpenMr. Raymond B. Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood, CA 91601; Mr. Raymond B. Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood CA 91601; "Dear Mr. Kesler: This responds to your February 29, 1992 letter askin the agency to reconsider its decision to deny your earlier petition for rulemaking to amend Federal motor vehicle safety standard No. 111, Rearview Mirrors. As explained below, your request is again denied, for the same reasons explained in the previous denial. You initially petitioned the agency to amend Standard No. 111 to require passenger side convex mirrors to have a radius of curvature of 25 inches and to have a plastic label with a ring indicator applied to these mirrors. After reviewing the petition, the agency denied your request, finding that (1) a safety need for a wider field of view for passenger side convex mirrors had not been established and (2) your suggested mirror system would, by comparison with currently specified convex mirror systems, have increased distortion and reduced a driver's depth perception and judgment about another vehicle's closing speed. (56 FR 42715, August 29, 1991). In your February 29, 1992 correspondence, styled a 'petition for reconsideration,' you restated your previous request for the agency to amend Standard No. 111 to require a mirror with a 25 inch radius of curvature and a plastic label with a ring indicator applied to these mirrors. That request does not provide any new information beyond what was presented in your initial petition. Petitions for reconsideration may be filed only in response to an agency rule. See 49 CFR 553.35(a). A denial of a petition for rulemaking is not a rule, since such denials do not amend any existing provision in the Code of Federal Regulations. Thus, your correspondence is not a petition for reconsideration. It is possible that there might be instances in which additional information has become available since the agency considered and denied the initial petition for rulemaking. If such a situation were to arise, the petitioner could file a new petition for rulemaking, asking again for the requested action based upon the newly available information. NHTSA would consider this as a petition for rulemaking. As noted above, your correspondence did not provide any new information. Thus, your correspondence is not a petition for rulemaking. Instead, your correspondence is simply a request for NHTSA to take the same action you previously asked us to take in a petition for rulemaking. Absent any new information, there is no reason for NHTSA to reexamine its previous conclusion on this matter. I would like to take this opportunity to clarify what appears to be a misunderstanding of the agency's regulations on your part. In your February 29, 1992 correspondence, you made the statement that your product 'should be approved to be made available to the driver as an optional choice.' In our notice denying your petition, the agency tried to make clear that products like your convex mirror with a ring sensor label are not prohibited from being installed on vehicles by the current requirements in Standard No. 111. However, such mirrors are permitted only as supplements to the required mirrors, for the safety reasons explained at length in the denial notice. See 56 FR 42716, August 29, 1991. Hence, your product may be installed as a supplement to the required mirrors on current vehicles, without any amendments to Standard No. 111. 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, Paul Jackson Rice Chief Counsel"; |
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ID: aiam4131OpenMr. Rich Demski, Engineering, Federal Motors Inc., P.O. Box 5000, Ocala, FL 32678; Mr. Rich Demski Engineering Federal Motors Inc. P.O. Box 5000 Ocala FL 32678; Dear Mr. Demski: This responds to your request for an interpretation of Federal Moto Vehicle Safety Standard (FMVSS) No 101, *Controls and Displays*. You asked about the identification requirements applicable to a coolant temperature telltale. According to your letter and an accompanying drawing, you are currently identifying the telltale with the identifying symbol for the coolant temperature telltale specified by Table 2 of FMVSS No. 101, and the words 'ENG WATER TEMP'. Noting that some of your vehicles have engines which are air-cooled rather than water-cooled, you asked if FMVSS No. 101 permits you to delete the word 'WATER' while otherwise continuing to identify the telltale as described above. As discussed below, the answer to your question is yes.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, the manufacturer has the responsibility to certify that its vehicles or equipment comply with applicable standards. The following represents our opinion based on the facts provided in your letter.; Section S5.2.3 of FMVSS No. 101 states in relevant part: >>>Except for informational readout displays, any display locate within the passenger compartment and listed in column 1 of Table 2 that has a symbol designated in column 4, shall be identified by that symbol. Such display may, in addition be identified by the word or abbreviation shown in column 3. . . . Informational readout displays may be identified by the symbol designated in column 4 of Table 2 or by the word or abbreviation shown in column 3. Additional words or symbols may be used at the manufacturer's discretion for the purpose of clarity. . . .<<<; The coolant temperature telltale is a display listed in Table 2 o FMVSS No. 101, and the symbol pictured in your letter is the identifying symbol for that telltale specified in column 4 of the table. Therefore, under section S5.2.3 of the standard, your use of that symbol to identify the coolant temperature telltale is sufficient identification regardless of what, if any, identifying words you provide for the purpose of clarity.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1333OpenMr. Charles R. Mosley, Chief of Police, Cleveland Police Department, Cleveland, MS 38732; Mr. Charles R. Mosley Chief of Police Cleveland Police Department Cleveland MS 38732; Dear Mr. Mosley: Your correspondence of October 17, 1973, on the subject of approval fo motorcycle helmets has been forwarded to this office for reply.; I am enclosing, for your information, a copy of Federal Motor Vehicl Safety Standard No. 218, which establishes requirements for motorcycle helmets effective March 1, 1974. The requirements of this standard will take precedence over other standards which cover like aspects of safety, pursuant to the National Traffic and Motor Vehicle Safety Act of 1966. There will be no list of 'approved' helmets, since all helmets manufactured for sale in the United States on or after the effective date must be certified to meet all requirements of the standard.; I trust the foregoing will be helpful. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1299OpenMr. George R. Semark, Safety Engineer - Vehicles, Planning & Development Center, Transportation Group, Sheller-Globe Corporation, 1200 East Kibby Street, Lima, OH 45802; Mr. George R. Semark Safety Engineer - Vehicles Planning & Development Center Transportation Group Sheller-Globe Corporation 1200 East Kibby Street Lima OH 45802; Dear Mr. Semark: This is in reply to your letter of October 11, 1973, requesting tha Motor Vehicle Safety Standard No. 217, Bus window Retention and Release,' be amended to include buses of the same design as school buses within the exemption from the emergency exit requirements specified for school buses' in S5.2.3 of the standard.; The NHTSA takes the position that buses of the same design as buse specifically designed as school buses, regardless of their intended use, are school buses for purposes of Standard No. 217. They are, therefore, exempt from the emergency exit requirements of the standard as specified in S5.2.3. No amendment of the standard is necessary.; Yours truly,Richard B. Dyson, Assistant Chief Counsel |
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.