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: aiam0640OpenMr. Thomas S. Pieratt, Jr., Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in reply to your letter of March 6, 1972, concerning th certification of pickup trucks that are modified while still in the hands of a dealer. You describe a situation in which the dealer removes the pickup body and sends the vehicle to a final-stage manufacturer for fitting with a service body.; We would consider modifications of the type you describe to b manufacturing under the National Traffic and Motor Vehicle Safety Act, and the Certification regulations (49 CFR Part 567). Because a completed vehicle is involved regulations governing Vehicles Manufactured in Two or More Stages (Part 568) do not apply.; One who remanufactures a completed vehicle assumes the responsibilit of any manufacturer of completed vehicles. The extent to which he may safely rely on the original GVWR, GAWR, and statement of conformity depends on what he has done to alter the vehicle. He is required to certify the vehicle by affixing his own label, and must take into account the effects of any modification he makes.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0132OpenMr. J.B.H. Knight, Chief, Development and Car Safety Engineer, Rolls-Royce Limited, Motor Car Division, Pym's Lane, Crewe, Cheshire, England; Mr. J.B.H. Knight Chief Development and Car Safety Engineer Rolls-Royce Limited Motor Car Division Pym's Lane Crewe Cheshire England; Dear Mr. Knight: Thank you for your letter of November 8, 1968, requesting clarification of the 30g horizontal inertia load direction specified in Standard No. 201, as published in the *Federal Register* on October 25, 1968.; In section S3.3.1(c), 'Subject the interior compartment door latc system to a horizontal inertia load of 30g in a longitudinal direction...' means both forward and rearward directions. In addition, the loads specified in S3.3.1(a) are applied in both the inboard and outboard and the up and down directions. This is consistent with similar type requirements in Standard No. 206.; You state that a forward and rearward 30g inertia load requirement i more stringent than the alternative procedure of S3.3.1(b), the barrier test. The Bureau believes, and one large manufacturer so stated in his comments, that the most meaningful test of the ability of an interior compartment door to remain closed is one which considers the distortion an deformation loads that occur in a collision. A barrier or equivalent dynamic test is the best way of realistically evaluating the ability of these doors to remain closed. The bureau, therefore, believes that the barrier test is as stringent a requirement as S3.3.1(c).; Sincerely, William Haddon, Jr., M.D., Director |
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ID: aiam1495OpenMr. D. L. Massy, Chief Engineer, American Snowblast Corporation, 4695 Ironton Street, Denver, CO 80239; Mr. D. L. Massy Chief Engineer American Snowblast Corporation 4695 Ironton Street Denver CO 80239; Dear Mr. Massy: In response to your May 13, 1974, question whether Standard No. 121 *Air brake systems*, has been delayed one year for vehicles which have 'drive on the front axle and front axle load of 18,000 pounds or more,' I would like to summarize our recent amendment of the standard.; On May 14, 1974, we delayed the effective date of the standard for al trucks and buses until March 1, 1975. Thereafter, trucks manufactured before September 1, 1975, that have a front steerable axle with a GAWR of 16,000 pounds or more, or a front steerable drive axle, need not meet certain stopping distance requirements if their brakes meet the retardation formula and values found elsewhere in the standard. These vehicles must still stay in the 12-foot lane and, during service brake stops, their wheels must not lock-up except for antilock-controlled lock-up. After September 1, 1975, the standard applies in full to this category of trucks.; There have been several additional changes in the standard which woul affect your products. They were published May 17, 1974, in the *Federal Register* (39 FR 17750).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1107OpenMr. John W. Leask, President, Engineering Dynamics Corp., 314 Great Road, Bedford, MA 01730; Mr. John W. Leask President Engineering Dynamics Corp. 314 Great Road Bedford MA 01730; Dear Mr. Leask: This is in response to your letter of March 26, 1973, concerning th test procedures of Motor Vehicle Safety Standard No. 215, *Exterior Protection.*; The test procedures of a motor vehicle safety standard prescribe th manner in which the NHTSA will test a vehicle. If a vehicle fails in our tests, the manufacturer may be subject to civil penalties unless he can establish that he exercised due care in manufacturing the vehicle. To establish due care he would have to demonstrate the steps he took to assure himself that the vehicle would comply when tested in accordance with the standard.; In the case of Standard No. 215, the agency will conduct its impac tests by using the pendulum specified in S6.2 of the standard. A manufacturer will not fail the standard if he does not use a pendulum. He may, if he chooses, test his vehicle by using a different device if he feels confident that the device he uses is equivalent in all relevant respects to the pendulum. If his vehicle fails in our pendulum tests, he will have to demonstrate the equivalency of his test device if he hopes to establish a defense in a proceeding brought by the agency.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1813OpenMr. Tatsuo Kato, Staff, Safety, Nissan Motor Co., Ltd., P.O. Box 1606, Englewood Cliffs, N.J. 07632; Mr. Tatsuo Kato Staff Safety Nissan Motor Co. Ltd. P.O. Box 1606 Englewood Cliffs N.J. 07632; Dear Mr. Kato: #This is in reply to your letter of January 21, 1975 requesting an opinion on whether either Federal Standard No. 109 or No. 119, or both, apply if Nissan equips a truck with a passenger car tire size (6.95 x 14-4PR). #Standards Nos. 109 and 119 apply to the tire only. consequently, the manufacturer of the tire has presumably made determination as to which standard applied when he manufactured the tire. There is no prohibition in the Federal safety standards to the use of a 'passenger car tire' on a truck. The truck manufacturer should, of course, ensure that the tire has a sufficient load carrying capacity for safe use on a truck. #Yours truly, #Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam2164OpenMr. George L. Leithiser, President, The Leithiser Company, 145 North Hartley Street, York, Pennsylvania 17404; Mr. George L. Leithiser President The Leithiser Company 145 North Hartley Street York Pennsylvania 17404; Dear Mr. Leithiser: This responds to your November 14, 1975, question whether an air-brake trailer that carries three spools of electric poser line and is designed to pay out and tension the three lines over towers would be required to comply with standard No. 121, *Air Brake Systems*.; Section S3. (*Application*) states in part that '... the standard doe not apply to any trailer whose unloaded vehicle weight is not less than 95 percent of GVWR [gross vehicle weight rating]...' It appears from your description that the trailer in question does not have either a passenger-carrying capacity of a rated cargo load. The unloaded vehicle weight would be equal to the GVWR and the trailer would be excluded from the requirements of the air brake standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1030OpenMr. Bill B. Wiggins, Wiggins & Christian, 602 First Federal Building, Post Office Box 994, Fort Smith, AR 72901; Mr. Bill B. Wiggins Wiggins & Christian 602 First Federal Building Post Office Box 994 Fort Smith AR 72901; Dear Mr. Wiggins: This is in response to your letter of February 27, 1973, concerning th application of the new Federal Odometer Disclosure Requirements to transfers between dealers.; The Federal requirements apply, with certain exceptions, to eac transfer of ownership of a motor vehicle. Some types of vehicles, such as heavy trucks and antique vehicles, are exempt. Passenger cars and lighter vehicles, however, are exempted only in the case of transfers of *new* vehicles from a manufacturer or a distributor to a dealer or from one dealer to another. The transfer of a *used* car or light truck, whether from dealer to dealer, dealer to wholesaler, or dealer to customer, must be accompanied by a disclosure statement.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1529OpenMr. Beller,Alfred Teves GMBH,6 Frankfurt/Main 2,Postfach 119155, Germany; Mr. Beller Alfred Teves GMBH 6 Frankfurt/Main 2 Postfach 119155 Germany; Dear Mr. Beller:#This responds to your May 10, 1974, request fo permission to stamp label information on hose assemblies in place of banding, and to reduce S9.2.5 burst pressure from 350 to 100 psi, and your further request for an interpretation of the status of an inline check valve as part of a vacuum brake hose.#The inline check valve is not subject to Standard No. 106, *Brake hose*, as a brake hose end fitting. In this configuration, the couplers depicted in your drawing are the clamps, and the check valve is a separate component to which the hose assemblies are attached.#The issue of stamping instead of banding will be answered in our upcoming Notice 11 in response to petitions for reconsideration of the brake hose standard.#Your petition for a reduction in the burst strength requirement for vacuum hoses is denied. The minimum burst pressure of 350 psi was established by the Society of Automotive Engineers in 1942, taking into consideration the effects of backfire pressure and the severe underhood environment to which vacuum hose may be exposed. Hoses with this burst pressure have provided excellent reliability and durability. We have no data to justify a reduction in burst strength in view of the two hazards just cited.#Sincerely,Robert L. Carter,Associate Administrator,Motor Vehicle Programs; |
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ID: aiam0142OpenMr. Jack Flynn, P.O.B. Manufacturing Company, 11100 Kenwood Road, Cincinnati, OH 45242; Mr. Jack Flynn P.O.B. Manufacturing Company 11100 Kenwood Road Cincinnati OH 45242; >>>Attention: Standards Department<<< Dear Mr. Flynn: Thank you for your letter of February 21, 1969, concerning glazin materials.; I am enclosing a copy of Federal Motor Vehicle Safety Standard No. 20 and, since you manufacture and distribute sealing compounds, a copy of Federal Motor Vehicle Safety Standard No. 212.; ASA Standard Z26.1-1966, incorporated by reference in Standard No. 205 can be obtained at a cost of $3.50 from the United States of America Standards Institute, 10 East 40th Street, New York 10016.; SAE Recommended Practice J673a, August 1967, incorporated by referenc in Standard No. 205, can be obtained from the Society of Automotive Engineers, Inc., Two Pennsylvania Plaza, New York, New York, 10001.; We are in the process of changing paragraph S.3.2 of Standard No. 205 You may want to keep up with future amendments to these and other standards, therefore, I am enclosing a copy of form HS-13, Mailing List Questionnaire and subscription information for the *Federal Register*. Either or both of these will enable you to receive information in your areas of interest in all future motor vehicle safety rulemaking actions.; Sincerely, Clue D. Ferguson, Director, Office of Standards o Crash-Injury Reduction, Motor Vehicle Safety Performance Service; |
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ID: aiam3769OpenGreg Kreshel, P.E., V.P. Production, Alloy Trailers, Inc., P.O. Box 19208, Spokane, WA 99219; Greg Kreshel P.E. V.P. Production Alloy Trailers Inc. P.O. Box 19208 Spokane WA 99219; Dear Mr. Kreshel: This is in reply to your letter of October 25, 1983, to Mr. Vinson o my staff, in which you question the practice by Fruehauf of replacing upper rear identification lamps with reflectors, on certain trailers. You asked if it were possible that the manufacturer would say that the header was too narrow for a light to fit.; I enclose a copy of an interpretation this office furnished Fruehau and the State of Wisconsin on June 18, 1981, which will clarify this issue. In summary, Fruehauf demonstrated to us the impracticability of mounting the identification lamps at the top of a vehicle of this configuration (principally because of the vulnerability of the wiring). At the time, Fruehauf expressed its concern about conspicuity of its vehicles and assured us that it would investigate ways to improve it in future production. Apparently it decided that adding reflectors at the top, at the body edges and towards the middle where the doors open, was the most satisfactory way to enhance conspicuity, given the design of the vehicle.; Thank you for your interest in this question. Sincerely, Frank Berndt, 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.