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 |
|---|---|
| search results table | |
ID: aiam2189OpenMr. Lewis Coffey, Chief Engineer, Gillig Brothers School Bus Co., 25800 Clawinter Rd., Hayward, CA 94540; Mr. Lewis Coffey Chief Engineer Gillig Brothers School Bus Co. 25800 Clawinter Rd. Hayward CA 94540; Dear Mr. Coffey: This is in response to your request for information concerning method of ensuring the compliance of school buses with the barrier crash test requirements of Federal Motor Vehicle Safety Standard No. 301-75, *Fuel System Integrity*.; Standard No. 301-75, while establishing minimum performance levels does not specify any particular design requirements for school bus fuel systems. A manufacturer is free to design his vehicles in the manner that he believes most appropriate to ensure compliance. To this end, you may find helpful information in a study by Dynamic Science entitled *School Bus Safety Improvement Program*. The NHTSA cannot assure you, however, that following the suggestions contained in the study will guarantee that your school buses will comply with the standard.; The study is filed in the NHTSA's public docket as document numbe 75-03-GR1. Copies may be obtained by writing to:>>>Technical Reference Branch, National Highway Traffic Safety Administration, Room 5108, 400 Seventh Street, S.W., Washington D.C. 20590<<<; You should refer to the following publication numbers: HS 801-615 -616, and -617.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam4553OpenMr. M. Iwase Technical Administration Dept. Koito Mfg. Co. Ltd. Shizuoka Works 500, Kitawaki Shimuzi--shi, Shizuoka-ken JAPAN; Mr. M. Iwase Technical Administration Dept. Koito Mfg. Co. Ltd. Shizuoka Works 500 Kitawaki Shimuzi--shi Shizuoka-ken JAPAN; Dear Mr. Iwase: This is to provide you with a clarification of m letter to you dated March l6, l988. Your second question was whether the minimum edge to edge separation distance between turn signal lamps and tail/stop lamps is required on a rear lighting array for motorcycles. I responded that 'The answer is yes, and the separation distance you have depicted in your drawings appears to comply with this requirement.' In actuality, the agency has required this separation only where a single motorcycle stoplamp/taillamp is mounted on the vertical centerline, and not when dual lamps are mounted on either side of the vertical centerline, the configuration depicted in your letter of January 25, 1988. Therefore, I am advising you that there is no legal requirement that the 4-inch separation distance be maintained in the configurations you depicted, and that we appreciate your continuing efforts to understand and comply with Federal Motor Vehicle Safety Standard No. 108. I enclose a copy of a letter from this Office dated November 2l, l984, which explains our views on motorcycle rear lighting configurations in more detail. Sincerely, Erika Z. Jones Chief Counsel Enclosure; |
|
ID: aiam3649OpenMr. H. Miyazawa, Director, Automotive Lighting, Engineering Department, Stanley Electric Co., Ltd., 2-19-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. H. Miyazawa Director Automotive Lighting Engineering Department Stanley Electric Co. Ltd. 2-19-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Miyazawa: This is in reply to your letter of November 23, 1982, to Mr. Elliott o this agency asking whether you may distinguish between U.S. and Japanese-manufactured lighting equipment subject to Federal Standard No. 108 by marking the lenses 'U.S.A. DOT' and 'JAPAN DOT', rspectively (sic).; As you know, the National Highway Traffic Safety Administration has no adopted the SAE standard on equipment marking, J759c. This means that the only marking subject to Standard No. 108 is that which certifies compliance to all applicable Federal motor vehicle safety standards, the DOT symbol. We believe that the intended proximity of the words 'Japan DOT' in your Japanese- manufactured equipment might create the impression that Stanley was certifying compliance to the requirements of the Japanese Ministry of Transport, rather than to those of the U.S. Department of Transportation. Therefore, we suggest that you place the word 'Japan' at the end of the line rather than adjacent to the 'DOT' symbol.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam0739OpenMr. Loy Rosner, Sales Manager, Checker Motors Sales Corporation, 35-30 38th Street, Long Island City, New York 11101; Mr. Loy Rosner Sales Manager Checker Motors Sales Corporation 35-30 38th Street Long Island City New York 11101; Dear Mr. Rosner: This is in reply to your letter o May 25, 1972, asking whether you, a a selling dealer, may install steel-belted radial ply tires in an 8-passenger Checker taxicab. You state that the vehicle is normally delivered to you with tires having the 'O' load range.; Federal Motor Vehicle Safety Standard No. 110 (49 CFR 571.110, cop enclosed) requires each passenger car to be equipped at the time of sale to a first purchaser with tires if certain minimum load carrying capacity, based on the weight of the vehicle. Any steel-belted radial ply tire that meets these load carrying requirements with respect to your vehicles may be installed by a selling dealer.; Radial tires of similar of Related sizes, but of different manufacture however, may have different load ratings. We suggest, therefore, that you contact Checker Motor Corporation for their recommendations as to which radial ply tires may be installs on these vehicles without adversely affecting the vehicle's conformity with Motor Vehicle Safety Standard No. 110.; Yours truly, Richard B. Dyson |
|
ID: aiam0097OpenMr. Toyotaro Yamada, Manager, Toyota Motor Company, Limited, 231 Johnson Avenue, Newark, NJ 07108; Mr. Toyotaro Yamada Manager Toyota Motor Company Limited 231 Johnson Avenue Newark NJ 07108; Dear Mr. Yamada: Thank you for your letter of July 23, 1968, to Mr. George C. Nield Acting Director, Motor Vehicle Safety Performance Service, concerning the requirements for turn signal and hazard warning signal flashers as specified by Motor Vehicle Safety Standard No. 108.; With certain exceptions, paragraph S3.3 of Standard No. 108 permits th use of combination lamps, reflective devices and items of associated equipment, provided the requirements for each lamp, reflective device and item of associated equipment are met. Therefore, a combination turn signal and hazard warning signal flasher may be used, provided the requirements for each signal (turn and hazard warning) are met.; You are correct in your understanding that Standard No. 108 an basically referenced SAE Standards J590 and J945 do not require operation of the flasher unit with only one signal bulb in the test circuit. The standard test circuit shown in Figure I of SAE Standard J823 indicates a minimum of two signal lamps and one pilot indicator lamp as the lamp load.; Thank you for writing. Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
|
ID: aiam1409OpenMr. J.C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Detroit, MI, 48121; Mr. J.C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Detroit MI 48121; Dear Mr. Eckhold: This is in reply to your letter of January 24, 1974, asking for a interpretation as to whether a rear lamp assembly design that Ford demonstrated to NHTSA representatives conforms to the location requirements of Standard No. 108. The assembly consists of three units which, from outboard to inboard, as a rear lighting assembly, comprise the tail lamp/stop lamp, backup lamp, and turn signal lamp.; Standard No. 108 specifies that stop lamps, tail lamps, and turn signa lamps be 'as far apart as practicable.' The standard does not specify a minimum separation distance of lamps, a maximum permissible location inboard, or location of one system relative to another. The determination of practicability in lamp spacing is to be made by the vehicle manufacturer, and the agency has generally afforded manufacturers some latitude in this interpretation.; Therefore, the configuration you have described and demonstrated woul not violate Standard No. 108. It should be noted, however, that it would be in conflict with the requirements for rear turn signals and stop lamps as proposed in Docket 69-19, Notice 3.; Sincerely, James B. Gregory, Administrator |
|
ID: aiam1928OpenMr. Harold D. Jones, Bock & Jones, 435 Main Street, New Madrid, MO 63869; Mr. Harold D. Jones Bock & Jones 435 Main Street New Madrid MO 63869; Dear Mr. Jones: This is in response to your letter of May 2, 1975, inquiring about th existence of regulations governing the manufacture, design, and on-the-road operation of trailers used to transport fertilizer while hitched to a pickup truck.; The National Highway Traffic Safety Administration has th responsibility of promulgating safety standards that set minimum performance requirements for vehicles manufactured and/or sold in the United States. There are five motor vehicle safety standards that apply to trailers. These standards relate to trailer lighting, tires, and braking systems (Standard No. 106-74, *Brake Hoses* (49 CFR Part 571.106), Standard No. 108, *Lamps, Reflective Devices and Associated Equipment* (49 CFR Part 571.108), Standard No. 116, *Motor Vehicle Brake Fluids* (49 CFR Part 571.116), Standard No. 119, *New Pneumatic Tires for Vehicles Other Than Passenger Cars* (49 CFR Part 571.119), Standard No. 121, *Air Brake Systems* (49 CFR Part 571.121)).; There is no safety standard that applies to the towing of a trailer The use of a safety chain to guard against release of the trailer may, however, be mandated by state law.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam0315OpenMr. Warren M. Barnett, c/o Barnett Sales and Service, 3710 Oxford Boulevard, Maplewood, MO 63143; Mr. Warren M. Barnett c/o Barnett Sales and Service 3710 Oxford Boulevard Maplewood MO 63143; Dear Mr. Barnett: This is in reply to your letter of February 23, 1971, requesting advic on the acceptability of your regrooving pattern for regrooved tires.; Enclosed is a copy of the Rules and Regulations on regrooved an regroovable tires as it appears in the *Federal Register* published January 24, 1969, under Section 369.7(a)(3) Requirements, 'After regrooving, the new grooves generated into the tread material and any residual original molded tread groove which is at or below the new regrooved groove depth, shall have a minimum of 90 linear inches of tread edges per linear foot of tire circumference.'; There are no measurements on your drawings to assist us in determinin if your zig-zag grooves and the three circumferencial grooves measure 90 linear inches. Three *straight* circumferential grooves would only provide approximately 72 linear inches.; The use of lateral cuts should substantially increase the tread edg measurements, providing the lateral cuts are from shoulder to shoulder to allow unobstructed fluid escape passages as required in Section 369.7(a)(5); Thank you for your interest in tire safety. Francis Armstrong, Director, Office of Standards Enforcement, Moto Vehicle Programs; |
|
ID: aiam0163OpenGeorge M. Hilgendorf, Esq., One North La Salle Street, Suite 4100, Chicago, Illinois 60602; George M. Hilgendorf Esq. One North La Salle Street Suite 4100 Chicago Illinois 60602; Dear Mr. Hilgendorf: Mr. Frank Coy, Special Assistant to the Under Secretary o Transportation, has asked that I respond to your letter of April 16, 1969, in which you ask whether a station wagon purchased in March of 1968, equipped with two ply tires, violates Federal Motor Vehicle Safety Standard No. 109.; The vehicle you purchased was apparently manufactured prior to April 1 1968, and therefore, it was not required to be equipped with tires conforming to Standard No. 109. However, even if the standard were applicable, because a tire is labeled '2-ply' it is not necessarily a non-conforming tire. Standard No. 109 does not specifically require tires to have a given number of plies. It does require that irrespective of any ply rating tires pass minimum performance tests. As to passenger cars, Standard No. 110 requires that passenger car manufactured after April 1, 1968, (1) must be equipped with tires that comply with Standard No. 109, and (2) the vehicle must not place a load on any of the tires greater than the load capacity of the tire specified in Standard No. 109.; Very truly yours, Howard A. Heffron, Chief Counsel |
|
ID: aiam0620OpenMr. O. J. Danker, Irvin Industries Inc., 51 Weaver Street, Greenwich, CT 06830; Mr. O. J. Danker Irvin Industries Inc. 51 Weaver Street Greenwich CT 06830; Dear Mr. Danker: This is in reply to your letter of February 23, 1972, in which you lis information you wish to label on child seats you will manufacture, and ask whether the information as presented will comply with Motor Vehicle Safety Standard No. 213. You state that a label containing the model number, date of manufacture, and the company's name and place of business will be permanently affixed to the product, while a separate legend, containing other information, will be molded on the bottom of the seat in raised letters at least 3/32 inches high.; The labeling scheme you with to use would conform to paragraph S4. ('Labeling') of Standard No. 213, providing, of course, the blank spaces for model number and date of manufacture are appropriately filled in. We would suggest, however, that that part of the molded legend beginning '. . . and there is a minimum of 19 inches vertical clearance between this seating . . .', to the end of that provision be simplified to be more understandable to an ordinary consumer.; We are pleased to be of assistance. 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.