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: nht75-2.22OpenDATE: 09/18/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Michelin Tire Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of July 9, 1975, inquiring as to the proper designation of plies on a truck tire constructed with two polyamide plies in the casing and two steel plies in the belt. The designation that you suggested ("Tread: 2 Steel Plies; Sidewall: 2 Polyamide Plies") is incorrect. The designation on such a tire should indicate the presence of four plies in the tread area and two in the sidewall area (with compositions in each case). Yours truly, ATTACH. JULY 9, 1975 Administrator -- National Highway Traffic Safety Administration, Department of Transportation Dear Sir: The Michelin Tire Corporation will be offering for sale in the U.S.A. truck tires which contain casing plies made of polyamide and belts made of steel. A typical tire would be constructed with two polyamide plies in the casing and two steel plies in the belt. Pursuant to paragraph S6.5(f) of Federal Motor Vehicle Safety Standard 119, we will mark such a tire as follows: Tread: 2 Steel Plies Sidewall: 2 Polyamide Plies Please advise us if this does not comply with the requirements of the regulation. Thank you. Yours truly, MICHELIN TIRE CORPORATION Technical Group; John B. White -- Engineering Manager, Technical Information Dept. |
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ID: nht75-2.23OpenDATE: 12/23/75 FROM: AUTHOR UNAVAILABLE; Mark Schwimmer; NHTSA TO: FILE TITLE: FMVSS INTERPRETATION TEXT: SUBJECT: VEHICLE REQUIREMENTS AND STANDARD NO. 119 On December 10, 1975, I received a telephone call from Mr. Dan Warner of Transportation Manufacturing Corporation in New Mexico (505 347-2011), concerning the scope of Standard No. 119. Mr. Warner asked whether the standard required vehicles to be equipped with tires conforming to it. I explained that Standard 119 applies only to tires, while vehicles would be the subject of Standard No. 120. I declined to predict the issue date or effective dates of Standard 120, but assured him that the scheme of effective dates would take into account the realities of production and inventories. Meaning of effective date of Standard No. 119 Attorney Advisor Interps. file On December 1, 1975, I received a telephone call from Mr. Nakajima of Bridgestone Tire Co. (213-320-6030) concerning the meaning of the March 1, 1975, effective date of Standard No. 119. He wanted confirmation that tires, for vehicles other than passenger cars, that were manufactured before that date are not subject to the standard's labeling requirements. I explained that his understanding was correct, citing 49 CFR @ 571.7. Mark Schwimmer |
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ID: nht75-2.24OpenDATE: 08/18/75 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: County of Los Angeles Road Department TITLE: FMVSS INTERPRETATION TEXT: Please forgive the delay in responding to your letter of April 28, 1975, concerning tires used on pull brooms. Federal Motor Vehicle Safety Standard No. 119, New pneumatic tires for vehicles other than passenger cars, (copy enclosed), specifies labeling and performance requirements for all tires designed for use on pull brooms. This standard applies to all such tires manufactured on or after March 1, 1975. There is presently no requirement, however, that vehicles be equipped with tires conforming to the standard. The National Highway Traffic Safety Administration has proposed and is considering the issuance of a new Standard No. 120, Tire selection and rims for motor vehicles other than passenger cars, which would require all new pull brooms manufactured after its effective date to be equipped with tires conforming to Standard No. 119. YOURS TRULY, TO: Dear Sir FROM: (Illegible Word) Date 3-6-75 Please send me all the necessary information you have about implement (Illegible Words) (Illegible Line) Thank you 76L265 Cdb 274 LOS ANGELES COUNTY LETTERGRAM TO: E.T. Driver FROM: Carl Morton Subject: Implement tires. Date: 4-28-75 Reply no N41-33 Our fleet of Pull Brooms are equipped with implement rib type tires. They are used 100% of the time on Highways. Please advise Thank you Carl Morton |
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ID: nht75-2.25OpenDATE: 08/18/75 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Holiday Rambler Corporation TITLE: FMVSS INTERPRETATION TEXT: I am writing in response to your letter of June 23, 1975, which inquired about the status of proposed Federal Motor Vehicle Safety Standard No. 120, Tire Selection and Rims for Motor Vehicles Other than Passenger Cars. The NHTSA expects to issue Standard No. 120 in the near future. It will not become effective September 1, 1975. An effective date which allows adequate lead time for manufacturers to prepare for compliance will be specified in a Federal Register notice when the rule is issued. Your second question, concerning the responsibility for providing GAWR and GVWR information for motor homes manufactured by you with chassis supplied by other manufacturers, will also be answered in that notice. SINCERELY, June 23, 1975 Administrator National Highway Traffic Safety Administration This letter is in reference to proposed F.M.V.S.S. 120. Holiday Rambler Corporation is a large manufacturer of recreational vehicles and Multipurpose Passenger Vehicles. As regards to the proposed Standard 120, we request your answer to the following questions. 1. What is the present status of this proposed standard; Does the effective date remain September 1, 1975? 2. HRC purchases from various manufacturers large numbers of chassis-cab type truck chassis for use in class "C" motor homes and commercial vehicles and will purchase a number of regular truck chassis for use in Class "A" Motor Homes. These manufacturers certify these "incomplete vehicles" at a specified G.V.W.R. and G.A.W.R. which our completed vehicle may not exceed. As regards proposed Standard 120 then, would the incomplete vehicle manufacturer be responsible for furnishing the required information label, or would HRC be responsible using such information as supplied by the incomplete vehicle manufacturer? Thank you for your time and consideration. If this letter requires further explanation, please feel free to call me at 219 862-4551. Otherwise you may address your reply to the address below. Your prompt reply would be greatly appreciated. Terrell T. Coleman Codes and Standards Co-Ordinator CC: S. MOSS; T. COLEMAN |
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ID: nht75-2.26OpenDATE: 11/10/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: DPD Mfg. Co., Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of September 22, 1975, requesting information concerning the applicability of Federal motor vehicle safety standards to automatic cruise control devices. As you were advised by telephone, Motor Vehicle Safety Standard No. 124, Accelerator Control Systems, does not preclude the use of cruise control units. While Standard No. 124 requires that the accelerator control device return to "idle" when the operator removes his foot from the accelerator or when the system itself fails, the term "idle position" is defined in S4.1 of the standard to include the position set by a throttle setting device. The rationale for not regulating automatic speed control devices is found in the preamble to the standard, issued on April 8, 1972 (37 FR 7097), which states: The rule does not contain requirements for automatic speed control devices. It was found that although nine recall campaigns involving 61,176 vehicles have concerned these devices, no relationship to accelerator overspeed accidents could be established from automatic speed controls. Of the 540 multi-disciplinary accident reports that were studied in formulating the final rule, none mentioned the automatic system. There are no other Federal motor vehicle safety standards which are concerned with the use of automatic cruise control devices. I trust this information will be useful to you. I have enclosed a copy of Standard No. 124 for your future reference. YOURS TRULY, September 22, 1975 U.S. Department of Transportation Federal Highway Administration National Highway Safety Bureau Enclosed is a copy of our request to you for automatic cruise control safety standards. Your telcon to us revealed that there were no safety standards applicable to cruise control. However, we need this information, in writing, to provide to our customers s required. Thank you for an early reply. DPD MFG. CO., INC. O. D. Hunter Director of Training and Publications May 21, 1975 U.S. Department of Transporation Federal Highway Administration National Highway Safety Bureau We are embarked on a project to manufacture automobile, automatic cruise control devices. Accordingly, please forward appropriate safety standards for our guidance. Thank you for an early reply. DPD MFG. CO., INC. O. D. Hunter Director of Training and Publications |
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ID: nht75-2.27OpenDATE: 03/11/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Joseph Lucas North America Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of February 7, 1975, in which you ask whether the control lever/throttle arm of diesel fuel injection equipment is considered part of the pump mechanism or part of the "linkage," i.e. the accelerator control system, within the meaning of Standard No. 124. The control lever/throttle is similar to the throttle lever referred to in Docket 69-20, Notice 5 (copy attached). In that notice, we established that the throttle lever is not part of the "driver-operated accelerator control system", but rather part of the fuel metering device and therefore does not fall within the ambit of Standard No. 124. Yours truly, ATTACH. February 7, 1975 Fred Schwartz -- Attorney Advisor, Office of the Chief Counsel, National Highway Traffic Safety Admin. Dear Mr. Schwartz: FMVSS 124 - Accelerator Control Systems Joseph Lucas North America Inc. is a subsidiary of Joseph Lucas (Industries) Ltd. of England. Two other subsidiaries, CAV Limited and Simms Motor Units Limited manufacture diesel fuel injection equipment, some of which is exported to the United States fitted to engines, or as sold by Joseph Lucas North America Inc. A question has arisen concerning the control lever/throttle arm on these pumps. Is this lever/arm part of the pump or it is part of the linkage? Enclosed are two publications: 1. Publication No. 2067/4 - CAV DPA Distributor Type Fuel Injection Pump with Mechanical or Hydraulic Governor. The Green arrows on pages 2, 66, 67, 68, and 69 point out the item in question. 2. Publication P29E - Simms Mechanical Fuel Injection Pump. The green arrows on pages 2 and 3 point out the item in question. We feel that this lever/arm is part of the injection pump, and not the linkage. Would you please confirm that our interpretation is correct? Any help which you could give us in correctly interpreting the definition of such a pump mounted lever/arm would be appreciated, so that we may correctly appraise the arrangements on other such pumps. Yours truly, JOSEPH LUCAS NORTH AMERICA INC. -- A. J. Burgess, Vice President (Technical) Enclosures |
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ID: nht75-2.28OpenDATE: 07/18/75 FROM: AUTHOR UNAVAILABLE; J. C. Schultz; NHTSA TO: Volvo of America Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 19, 1975, seeking an interpretation of Standard No. 124, Accelerator Control Systems, with regard to an accelerator control system which contains either elements in parallel or a complete parallel system. The requirements of S5.2 of Standard No. 124 are met if, after a severance or disconnection of any component of the accelerator control system, the throttle returns to the idle position within the time specified in S5.3, measured from the first removal of the opposing actuating force by the driver, or from the disconnection or severance. You are correct in your interpretation that Standard No. 124 is intended to protect against a single severance, and that there are no requirements in Standard No. 124 concerning the severance or disconnection of the remaining one(s) of two or more parallel elements in an accelerator control system. SINCERELY, June 19, 1975 James Schultz, Chief Counsel National Highway Traffic Safety Administration Re: Request for Interpretation of FMVSS No. 124 Section S5.2 of FMVSS No. 124 - Accelerator Control Systems specifies requirements for return of the throttle to the idle position ". . . whenever any one component of the accelerator control system is disconnected or severed at a single point." The operation of this section of the standard is clear when the accelerator control system consists of a single series of links and/or cables and/or other connecting devices. Severance or disconnection at any one point will result in a loss of control by the operator and the return of the throttle to its idle position. The situation is not as clear when the accelerator control system contains either elements in parallel or a complete parallel system. In this case if one of two or more parallel links, cables or other connecting devices is severed or disconnected, the operator still maintains control of the accelerator control system. Since the throttle does not return to the idle position at the time of severance or disconnection, the requirements of S5.2 will be met if the system returns to idle within the time limit specified by S5.3, measured from the first removal of the opposing actuating force by the driver. With regard to the above situation it is our understanding there are no requirements in FMVSS No. 124 concerning the severance or disconnection of the remaining of two or more parallel elements in an accelerator control system since S5.2 refers to the severance or disconnection of only one component. Thus the requirements of S5.2 would be met if such a system returns to the idle position within the specified time after the removal of the opposing actuating force. Your verification of our understanding of the standard's applicability to parallel links or systems would be appreciated. Thank you for your prompt consideration of this request. VOLVO OF AMERICA CORPORATION Product Engineering and Development Donald J. Gobeille, Jr. Product Safety Engineer CC: E. SKARIN/AB VOLVO |
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ID: nht75-2.29OpenDATE: 10/01/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of September 17, 1975, in which you ask whether a permanent label affixed to the inside surface of a hubcap would satisfy the requirements of a new proposed paragraph S3.2 of Standard No. 211. The intent of the proposed labeling requirements, part of a general identification scheme for motor vehicle equipment manufacturers, is to ensure rapid and efficient identification of the manufacturer of a defective or nonconforming part or vehicle. The placement of an identifying label on the inside of a hubcap would not hinder rapid identification of the manufacturer. Therefore, the National Highway Traffic Safety Administration would consider that a label that is permanently affixed to the inside surface of a hubcap and contains the information specified in proposed paragraph S3.2 of Standard No. 211 would comply with the requirements of S3.2. We hope this answer is satisfactory. If you have any other questions, please contact us. YOURS TRULY, September 16, 1975 Frank Berndt Chief Council National Highway Traffic Safety Administration Re: Interpretation of Proposed Rule FMVSS 211 This is to ask for your interpretation of FMVSS 211, S.3.2 which was proposed in Docket No. 73-14; Notice 3, published on March 19, 1975. S.3.2 (labeling requirement) states, "Each wheel nut, wheel disc and hubcap shall be permanently and legibly marked or labeled with . . . . .". As the location of the mark or the label is not specifically mentioned in S.3.2, may we understand that it is in compliance with S.3.2 to affix permanently and legible the label on the inside surface of the hubcap? Thank you for your attention to the above question. We look forward to hearing your interpretation of the above. NISSAN MOTOR CO., LTD. Tokio Iinuma Staff, Safety |
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ID: nht75-2.3OpenDATE: 10/28/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Swan and Woodford TITLE: FMVSS INTERPRETATION TEXT: This responds to your August 27, 1975, request for standards applicable to glass-belted tires with the size designation H78-15 which were standard equipment on a 1973 Ford automobile. Such tires are subject to Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires -- Passenger Cars, a copy of which is enclosed. YOURS TRULY, SWAN & WOODFORD August 27, 1975 National Highway Traffic Safety Administration Re: Standards for Firestone Brand Tires This letter is to inquire of any available information regarding standards for the below listed equipment. Size H-78-15 glass-belted Firestone brand tires; standard equipment on 1973 Ford automobile. I am particularly interested in a standard as it applies to "blow outs" at 65 miles per hour on an improved road with tires having been driven 14,000 miles. ("Blow-out" occurred in inner sidewall Thanking you in advance for your cooperation. C. BRAD WOODFORD |
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ID: nht75-2.30OpenDATE: 11/25/75 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Dayton Wheel Prod., Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of August 27, 1975 (117-1), requesting an interpretation of paragraph S3 of Federal Motor Vehicle Safety Standard No. 211, Wheel Discs, Wheel Nuts, and Hub Caps. Our interpretation of Standard No. 211 is that S3 prohibits winged projections that do not extend beyond the outer edge of the tire or rim, as well as those that do. We hope that this information will be of assistance. If you have any further questions, please contact us. Sincerely, ATTACH. DAYTON WHEEL PRODUCTS, INC. August 27, 1975 U.S. Department of Transportation -- National Highway Traffic Safety Administration Dear Sirs: This letter is to request an interpretation of Motor Vehicle Safety Standard No 211, section S3. We need to know what determines a "projection". We maintain that a "projection" must extend outside the plane drawn through the outermost side of the tire or rim. Any portion of the wheel that does not project beyond that plane would not constitute a hazard to pedestrians. Please send your comments on the above and a clarification on how the projection should be determined. Thank you for your assistance. Sincerely, James J. Schardt -- President c.c. Robt. E. Weltzer -- Highway Safety Management Specialist, DOT-NHTSA; Reference 117-1 |
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Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.