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: aiam0192OpenMr. Warren M. Heath, Commander, Engineering Section, Department of California Highway Patrol, P. O. Box 898, Sacramento, CA 95804; Mr. Warren M. Heath Commander Engineering Section Department of California Highway Patrol P. O. Box 898 Sacramento CA 95804; Dear Mr. Heath: Thank you for your letter of December 8, 1969, concerning alternat flashing of side marker lamps with turn signal lamps.; Alternate flashing sidemarker lamps are permitted in paragraph S3.5 o Motor Vehicle Safety Standard No. 108 for signaling purposes, however, they must not impair the effectiveness of the turn signal lamps as required in paragraph S3.1.2.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam3002OpenMr. Donald Beyer, National Service Manager, Vespa of America Corp., 355 Valley Drive, Brisbane, California 94005; Mr. Donald Beyer National Service Manager Vespa of America Corp. 355 Valley Drive Brisbane California 94005; Dear Mr. Beyer: I regret the delay in responding to your letter concerning the meanin of 'suppressed zero needle' as used in connection with Federal Motor Vehicle Safety Standard 127, *Speedometers and Odometers*. This term means simply that the lowest numbered speed on the speedometer scale may be greater than zero. Therefore, the lowest speed measured by the speedometer needle bay be greater than zero.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0457OpenMr. J. G. Abbott, Transportation Chemicals, Development & Service, Dow Chemical Europe, S.A., Todi-Strasse 68, 8810 Horgen 2, Switzerland; Mr. J. G. Abbott Transportation Chemicals Development & Service Dow Chemical Europe S.A. Todi-Strasse 68 8810 Horgen 2 Switzerland; Dear Mr. Abbott: This is in reply to your letter of September 24 to Francis Armstron regarding the effective date of the new Federal motor vehicle brake fluid standard, No. 116.; The effective date of March 1, 1972, means that any vehicl *manufactured* on or after that date for sale in the United States must be equipped with brake fluid meeting Motor Vehicle Safety Standard No. 116.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam0323OpenMr. Phillip N. Shrake, Standards Director, Recreational Vehicle Institute, 2720 Des Plaines Avenue, Des Plaines, IL 60018; Mr. Phillip N. Shrake Standards Director Recreational Vehicle Institute 2720 Des Plaines Avenue Des Plaines IL 60018; Dear Mr. Shrake: This is in reply to your letter of April 8, 1971, requesting confirmation of your understanding as to two sections of Standard No. 208, Occupant Crash Protection.; You are correct in reading section S4.3 to provide options for truck and multipurpose passenger vehicles with a GVWR of 10,000 pounds or less.; You are also correct in reading S4.2.2 and S4.2.3 to mea 'chassis-mount camper' when the term 'vehicles carrying chassis- mount campers' is used.; The petitions filed by RVI requesting amendments to Standards No. 20 and 210 are under active consideration and you should expect to receive an answer in the very near future.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam4334OpenThe Honorable William Proxmire, United States Senate, Washington, DC 20510; The Honorable William Proxmire United States Senate Washington DC 20510; Dear Senator Proxmire: This is in reply to your recent inquiry on behalf of your constituent Todd Suer of Janesville.; Mr. Suer, in his letter to you of April 15, 1987, refers to cars 'tha have extra clear head lights besides the ones that are built in ' and asks if there is a law against them.; We are not familiar with the lighting equipment that Mr. Suer mentions It is not part of the front lighting equipment required by the Federal motor vehicle safety standards. It appear to be aftermarket, accessory equipment, and as such, its use is subject to regulations under State law. We suggest that Mr. Suer direct his complaint to State or local authorities.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0084OpenMr. George W. S. Smith, President, Ideal Manufacturing Company, 1107 South Seventh Street, Oskaloosa, IA 52577; Mr. George W. S. Smith President Ideal Manufacturing Company 1107 South Seventh Street Oskaloosa IA 52577; Dear Mr. Smith: Thank you for your letter of June 10, 1968, to Mr. J. O'Gorman of thi Bureau, concerning the requirements for side reflex reflectors as specified in Motor Vehicle Safety Standard 108.; As noted in your letter, paragraph S3.1.1.6 of Standard No. 108 effective January 1, 1969, permits until January 1, 1970, the use of two side reflex reflectors on each side of vehicles that are less than 80 inches in overall width. On and after January 1, 1970, Standard No. 108 requires that these vehicles be equipped on each side with two side reflex reflectors and two side marker lamps.; Thank you for writing. Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam1072OpenMr. Terry Coleman, Senior Project Coordinator/Federal Codes, Holiday Rambler Corporation, Engineering Department, 1055 East Lincoln Street, Nappanee, IN 46550; Mr. Terry Coleman Senior Project Coordinator/Federal Codes Holiday Rambler Corporation Engineering Department 1055 East Lincoln Street Nappanee IN 46550; Dear Mr. Coleman:#This is in reply to your letter of March 20, 1973, t this agency asking about the applicability of paragraph S4.1.2 of Federal Motor Vehicle Safety Standard No. 104 to vehicles other than passenger cars.#Your understanding is correct that the standard establishes wiped area requirements only for passenger car windshields. The NHTSA is engaged in research with the intent of establishing an all- weather visibility standard, combining Standards No. 103 and 104, that would among other things extend the windshield wiped area requirements to vehicles other than passenger cars. However, it is not possible to say when we will issue a rulemaking proposal on this subject.#Sincerely, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam3525OpenMr. Leon W. Steenbock, Project Engineer, FWD Corporation, Clintonville, WI 52929; Mr. Leon W. Steenbock Project Engineer FWD Corporation Clintonville WI 52929; Dear Mr. Steenbock: This responds to your recent letter asking whether Safety Standard No 205, *Glazing Materials*, permits the use of Items 4 and 5 rigid plastics in rear windows on fire trucks. You were confused because the 'ANS Z26' standard permits rigid plastics in these locations, yet Standard 205 is silent on the issue.; The fact that Standard No. 205 does not specifically state that Items and 5 rigid plastics may be used in rear windows in trucks does not mean that such use is not permitted. The 'ANS Z26' standard is incorporated by reference in Standard No. 205 (paragraph S5.1.1). Therefore, glazing materials that conform with 'ANS Z26' may be used in the locations specified in that standard. In addition to the requirements and specified locations in 'ANS Z26,' Standard 205 includes other locations and requirements for additional types of glazing, as well as other locations for the Items of glazing that are specified in 'ANS Z26.'; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0184OpenMr. Erich K. Dorfner, Product Development Manager, Thompson Aircraft Tire Corporation, 160 Beacon Street, South San Francisco, California 94131; Mr. Erich K. Dorfner Product Development Manager Thompson Aircraft Tire Corporation 160 Beacon Street South San Francisco California 94131; Dear Mr. Dorfner: In response to your letter of November 6, 1969, the Department o Transportation hereby assigns number *211* to the Thompson Aircraft Tire Corporation, South San Francisco, California, as its approved code mark. The approved code mark is for use in identifying the tire manufacturer in accordance with S4.3 of the Federal Motor Vehicle Safety Standard No. 109 and the National Traffic and Motor Vehicle Act of !966 (15 USC 1421(1)).; You are cautioned that the approved code mark at the present time i for use only on new pneumatic passenger car tires.; Sincerely, Roger H. Compton, Director, Office of Standards on Acciden Avoidance, Motor Vehicle Safety Performance Service; |
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ID: aiam1214OpenMr. Gil W. Bellamy, Administrator, Oregon Traffic Safety Commission, Room 313 Highway Building, Salem OR 97310; Mr. Gil W. Bellamy Administrator Oregon Traffic Safety Commission Room 313 Highway Building Salem OR 97310; Dear Mr. Bellamy: Thank you for your letter of July 23, 1973, enclosing an amende version of Oregon House Bill 2721.; We note that Section 2 of the Bill no longer requires a mandator green- yellow-red rear mounted lighting system but specifies that it may be used on an optional basis, in accordance with the suggestions in Mr. Wilson's letter of July 20, 1973. In order to avoid preemption under the National Traffic and Motor Vehicle Safety Act, ORS 483.412(3)(b) [Section 3] should be similarly amended to substitute 'may' for 'shall' so that all references to a mandatory system are removed from the Bill.; Sincerely, James B. Gregory, Administrator |
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.