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 |
|---|---|
ID: nht73-2.41OpenDATE: 02/22/73 FROM: E.T. DRIVER -- NHTSA; SIGNATURE BY CHARLES A. BAKER TO: N. H. Dachs TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of January 30, 1973, relating to the safety standard for automobile accelerators. On April 8, 1972, the National Highway Traffic Safety Administration (NHTSA) issued Federal Motor Vehicle Safety Standard No. 124, Accelerator Control Systems. This standard established requirements for accelerator control systems, effective September 1, 1973. In addition to the standard, two amendments were issued; one in September 1972 and the other in January 1973. Copies of the standard, plus the amendments, are enclosed for your review and further information. The NHTSA has not prepared or issued any reports relating to the safety standard; however, many comments were received in response to the proposed rule making action. These responses may be reviewed in the Docket Section, NHTSA, Room 5241, 400 Seventh Street, S.W., Washington, D.C. 20590. We trust that the above information will be useful to you. If we can be of any further service, please let us know. |
|
ID: nht73-6.23OpenDATE: December 10, 1973 FROM: Richard B. Dyson -- Assistant Chief Counsel, NHTSA TO: Robert R. Aronson -- President, Electric Fuel Propulsion Corp. TITLE: None ATTACHMT: Attached to letter dated 11-26-73 from Robert R. Aronson to Lawrence Schneider (Chief Counsel, NHTSA) TEXT: This is in reply to your letter of November 26, 1973, inquiring about the applicability of Standard No. 301 to your vehicles' gasoline-powered water heaters. Standard No. 301 was promulgated in order to reduce the incidence of deaths and injuries resulting from fuel-related fires. The standard seeks to accomplish this end by specifying performance requirements which must be met by a motor vehicle's fuel system. Although the fuel systems primarily regulated by the standard are those which propel the vehicle, nothing in the standard limits its application to those systems. A fuel system which powers another aspect of the vehicle's operation, such as the gasoline- powered Stewart Warner Water Heater, is susceptible to the same hazards as the more commonly encountered fuel system, and thus they must be regulated in the same manner in order to fulfill the purposes of Standard No. 301. In summary, the 2-quart fuel tank to which you refer is subject to the requirements of Standard No. 301. |
|
ID: nht91-7.4OpenDATE: November 11, 1991 FROM: Wallace F. Forbes -- Planar Support Systems, Inc. TO: Office of the Chief Counsel, NHTSA TITLE: None ATTACHMT: Attached to letter dated 12-30-91 from Paul Jackson Rice to Wallace F. Forbes (A38; VSA 102(4); VSA 108(a)(2)(A)) TEXT: Our company is in the process of designing a portable back support product which people would be likely to use in their automobiles as well as in other environments. In view of its possible use in automobiles, we would like to be advised of any safety standards, guidelines or requirements that may pertain to such a product or the materials used in its construction. This back support system will include a headrest as an optional feature. Thank you for your advice. |
|
ID: nht72-3.42OpenDATE: 11/13/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 14, 1972, on the subject of the test dummy specifications of Standard No. 208. I apologize for our delay in replying. The alignment procedures of S8.1.11 of the standard cause the head to be aligned so that its vertical axis is almost in the same plane as the dummy's back. The necks on most commercial dummies are made of rubber and are installed at such an angle that, as you have noted, the specified head alignment cannot be maintained. To correct this misalignment, the necks must be adjusted by shims or other means so that the correct alignment can be maintained. The center of gravity of the upper thorax is approximated by dimensions C and D in Table I and Figure 1 of SAE Recommended Practice J963. The precise location may vary slightly from one dummy model to another due to variances in the distribution of mass in the thoracic area. |
|
ID: nht72-2.7OpenDATE: 10/16/72 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: North American Rockwell Automotive Technical Center TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of September 28, 1972, requesting an extension of the time allowable to petition for reconsideration of Federal Motor Vehicle Safety Standard No. 105a, Hydraulic Brake Systems. You base your request upon the alleged necessity for testing to determine front axle capability under paragraph S5.1.16, Spike stops. This paragraph is substantially similar to paragraph S4.13 in the proposal published on November 11, 1970. You did not indicate in your comments to Docket No. 70-27 dated February 1, 1971, that the spike stop proposal needed further time for your evaluation. In our view, the 22 months that elapsed between issuance of the proposal and the final rule should have afforded you ample opportunity for testing. In any event, the time allowed for filing of petitions for reconsideration is fixed at 30 days by 49 CFR @ 553,35(a), and we generally do not extend this time. We will, however, consider the substantive comments you submitted concerning paragraph S5.4.2 and respond to them in due course. |
|
ID: 18592.wkmOpenMr. G. S. Edington Dear Mr. Edington: This responds to your letter to this agency regarding the metrication of Federal Motor Vehicle Safety Standard (Standard) No. 119, New pneumatic tires for vehicles other than passenger cars. You referred to the final rule published in the Federal Register on May 27, 1998, (63 FR 28912) in which we changed paragraph S6.5(d) to require that the maximum load ratings and corresponding maximum inflation pressures be shown in metric numbers, followed by English numbers in parentheses, effective May 27, 2003. You asked whether you could continue to show the load ratings and inflation pressures in English units, followed by metric units in parentheses after the May 27, 2003 effective date. The answer is no. Standard No. 119, subsection S6.5, Tire markings, specifies the labeling that is to be placed on tire sidewalls, the placement of the markings on the sidewalls, and the measurements of the required markings. Paragraph (d) requires that the maximum load rating and the corresponding tire inflation pressure of the particular tire be shown as follows: For tires rated for single and dual load:
|
|
ID: nht92-2.49OpenDATE: 11/03/92 FROM: LEO WENSTRUP -- MANAGER - TECHNICAL SERVICES, EATON CORPORATION AXLE & BRAKE DIVISION TO: OFFICE OF CHIEF COUNSEL, NHTSA COPYEE: J. DOAN; B. PICKORNIK; B. WALTER TITLE: BRAKE DYNAMOMETER CERTIFICATION TESTING ATTACHMT: ATTACHED TO LETTER DATED 12-29-92 FROM PAUL J. RICE TO LEO WENSTRUP (A40; STD, 121) TEXT: To Whom It may Concern, Our company has been requested by a customer who uses our brake products in a City refuse fleet to pursue alternative lining materials. The reason for their request is the current lining formulation is very aggressive and prone to noise. This lining was chosen based on standard dynamometer certification testing as required by Section S5.4 and S6.2 of FMVSS-121 to a GAWR and rolling radius in excess of this fleets vehicle specifications. It was decided to conduct certification testing to the exact vehicle specifications to optimize the brake performance for this customer. In reviewing the vehicles specifications, it was noted the maximum vehicle speed is governed to 45 MPH. This is below the initial speed of the fade portion of the FMVSS-121 dynamometer certification protocol in section S5.4.2. At what speed should the fade portion of this certification be conducted in light of the fact the vehicle is incapable of meeting the test conditions? I thank you in advance for your office's review of this enquiry and a timely response. |
|
ID: nht78-3.9OpenDATE: 03/08/78 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: O'Sullivan Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 3, 1978, to Mr. Guy Hunter of my staff, requesting assignment of a "DOT" code number for purposes of Federal Motor Vehicle Safety Standard (FMVSS) No. 205, Glazing Materials. You state that you supply vinyl plastic sheeting to your customer who, in turn, laminates and polishes this sheeting for use as glazing in the rear window opening of convertibles. Under paragraph S6 of FMVSS No. 205 (a copy was previously mailed to you), the assignment of a code number is restricted to prime glazing material manufacturers. Prime glazing material manufacturers are those who either fabricate, laminate, or temper the glazing material. Since you merely supply the material to your customer who then laminates and polishes it for use as glazing, you are not considered the prime manufacturer and assignment of a code number to you is not appropriate. Your customer is the prime manufacturer in this case and it is his responsibility to certify that his glazing meets the requirements by the means specified in FMVSS No. 205. If I can be of further help, do not hesitate to contact me. Sincerely, ATTACH. O'Sullivan Corporation February 3, 1978 Guy Hunter -- NATIONAL HIGHWAY & TRAFFIC SAFETY ADMINISTRATION Dear Mr. Hunter: We used to calender clear vinyl plastic sheeting which was subsequently laminated and polished and used in the automobile rear windows. Our former customer recently ordered another quantity of this plastic. We understand that suppliers of this type of materials must obtain a D.O.T. number and we would appreciate having one assigned to us. Yours very truly, R. C. Evans, Vice President Director of Research & Development cc: J. S. Campbell; C. R. Creamer; N. R. Hamblin |
|
ID: nht88-1.10OpenTYPE: INTERPRETATION-NHTSA DATE: JANUARY 4, 1988 FROM: ROBERT J. KAUFMAN -- GINGOLD, KAUFMAN & CHAIKEN TO: NHTSA TITLE: GK&C FILE NO. 1012-271 ATTACHMT: MEMO DATED 2-18-88, FROM ERIKA Z. JONES, TO ROBERT J. KAUFMAN, TITLED: GK & C FILE # 1012-271 TEXT: This law firm represents a Volvo dealership in the State of Georgia, which dealership purchases certain accessory products for the aftersale market. Specifically, one of the products which my client acquires is an armrest to be installed in a Volvo 240 s eries automobile, which product is acquired from a company known as Auto Accessories, Inc., located at P. O. Box 10044, New Iberia, Louisiana 70562. Recently, my client has received a circular from Auto Accessories, Inc., relative to the installation pr ocedure for the "240 armrest", which procedure ostensibly was either approved, mandated or suggested by the Department of Transportation. A copy of the circular is enclosed for your review. It would greatly be appreciated if you could furnish to the undersigned a detailing of the specific installation procedures for the "240 armrest". Moreover, it would be appreciated if you would advise the undersigned as to whether these procedures are merely suggested or required. Of additional concern is the question as to whether the installation procedure which the Department of Transportation has suggested satisfies the "inoperative" or "inaccessible" test as alluded to in the National Traffic and Motor Vehicle Act of 1966, Standard No. 208, Section S7.2 and Section 108(A) (2) (a). Finally, if your office has any additional information relative to this specific accessory, to-wit: the "240 armrest", or anything related to its installation, operation or tests or studies pertaining to it, it would be most helpful if you could furni sh to the undersigned copies of all relevant data. Naturally, we would be more than happy to be invoiced for any costs incurred in the production of these documents. Obviously, it is my client's firmest desire to provide the utmost in safety to its customers, and, consequently, my client is most desirous of insuring that the accessories which it installs and the method of installation are of the highest caliber an d any information that you could provide to facilitate that endeavor will be received most graciously. Thank you for your kind assistance and cooperation. ENCLOSURES |
|
ID: nht80-2.34OpenDATE: 05/07/80 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Hon. Samual S. Stratton - H.O.R. TITLE: FMVSS INTERPRETATION TEXT: MAY 7 1980 NOA-30 Honorable Samuel S. Stratton House of Representatives Washington, D.C. 20515 Dear Mr. Stratton: This responds to your recent correspondence requesting information on behalf of the Schenectady County Traffic Safety Board. The Safety Board is concerned that many new or converted propane-powered vehicles carry no identification indicating that the vehicles contain propane fuel instead of gasoline. The Safety Board states that this creates a dangerous situation for firemen, policemen or other emergency personnel who respond to accidents involving propane-powered vehicles. You were asked to initiate legislative action to require such identification on these vehicles. The National Highway Traffic Safety Administration issues safety standards and regulations governing the manufacture of new motor vehicles and motor vehicle equipment. Therefore, if there were a demonstrated safety need for identification on propane vehicles, the agency would have authority under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381, et seq.) to require a label or tag as was suggested by the Safety Board. Please inform the Safety Board that it should petition the agency to initiate rulemaking action to establish such a requirement if it has information or evidence indicating that a safety problem does indeed exist. I have enclosed a copy of the regulation which explains what must be included in a Petition for Rulemaking. The agency has no authority under the Vehicle Safety Act to regulate used motor vehicles and, therefore, could not require an identification label on a used vehicle that is converted to propane fuel. Congress left this jurisdiction to the individual States. Consequently, Congressional action or action at the State level would be required to mandate identification labels on used vehicles. I am also enclosing a copy of a letter of interpretation the agency issued last August which discusses the implications under Federal law of installing auxiliary fuel tanks in motor vehicles and of converting vehicles to the use of propane gas. Although not directly related to the Safety Board's concern, it might be of interest. I hope this has been responsive to your inquiry. If you have any further questions, please contact Hugh Oates of my staff at 202-426-2992. Sincerely, Frank Berndt Chief Counsel 3 Enclosures: Constitutent's correspondence Copy of regulation Copy of August letter March 26, 1980 Hon. Samuel Stratton House of Representatives United States Congress Washington, D.C. 20590 Dear Congressman Stratton: The Schenectady County Traffic Safety Board is concerned that many new or converted propane-propelled vehicles carry no indication that these vehicles contain propane fuel tanks. This lack of information could have very tragic results if a propane-propelled vehicle is involved in an accident or catches on fire. Firemen, policemen, or other emergency personnel responding to the scene will be unaware of the danger presented by the propane fuel tanks and will not take the proper precautions required when working near such a highly volatile substance. The Traffic Safety Board strongly recommends that new or converted propane-propelled vehicles be clearly marked as carrying propane fuel tanks. The marking should be in a conspicuous location and might be similar to the markings that are currently used on many vehicles to identify them as being diesel-powered or as using only unleaded fuel. The Traffic Safety Board asks for your help in initiating legislative action on this matter. Please contact us if you have any questions.
Sincerely, John L. McGovern Chairman JJMG/db cc: Traffic Safety Board Members Executive Secretary |
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.