
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: nht89-2.31OpenTYPE: INTERPRETATION-NHTSA DATE: 07/10/89 FROM: STEPHEN P. WOOD -- NHTSA ACTING CHIEF COUNSEL TO: SADATO KADOYA -- MANAGER, SAFETY ENGINEERING MAZDA (NORTH AMERICA), INC. RESEARCH & DEVELOPMENT CENTER TITLE: NONE TEXT: Dear Mr. Kadoya: This is to provide you with a clarification of our letter to you dated November 3, 1988, based upon your telephone conversation with Taylor Vinson of this Office. Our letter advised you that Standard No. 108 did not preclude the use of replaceable bulb headlamps with adjustable reflectors. In reply, you have cited two provisions of the standard which appear in conflict with this interpretation. With respect to a headlamp equipped with one or two HB1 light sources, S4.1.1.36(e)(1) states that "There shall be no mechanism that allows adjustment of an individual [HB1] or adjustment of reflector aim with two [HB1s]." To similar effect with respect to HB3 and HB4 li ght sources is S4.1.1.36(f)(1). Standard No. 108 has been amended effective June 8, 1989, and the corresponding requirements are now S7.5(d)(1) and (e)(1). Each has been revised to state "There shall be no mechanism that allows adjustment of an individ ual light source, or, if there are two light sources, independent adjustment of each reflector." We believe that the revised wording of the new sections clearly allow the adjustment of single reflectors in single light source replaceable bulb headlamps, and dual reflectors in dual-light source replaceable bulb headlamps, provided that the reflectors are not capable of independent adjustment. Further, new S7.7.2.2 specifically addresses how moveable reflectors must operate. The intent of these sections is to prohibit headlamp designs in which the bulb alone is adjusted to aim the headlamp since this is contrary to mechanical aim requirements, or, where there is more than one reflector in a headlamp, designs in which each reflector may be adjusted independently, since this is also contrary to achieving precise mechanical aim. Thank you for bringing this matter to our attention. Sincerely, |
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ID: nht89-2.32OpenTYPE: INTERPRETATION-NHTSA DATE: 07/11/89 FROM: BUTLER DERRICK -- CONGRESS TO: STEVE WOOD -- ACTING CHIEF COUNSEL NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 07/31/89 FROM STEPHEN P. WOOD -- NHTSA TO BUTLER DERRICK -- CONGRESS; REDBOOK A31; STANDARD 208 TEXT OF THE RULING BY THE ILLINOIS SUPREME COURT UPHOLDING THE STATE'S LAW REQUIRING SEAT BELT USE BY DRIVERS AND FRONT SEA T PASSENGERS IN AUTOMOBILES; DATE 10/01/86 TEXT: I am writing to inquire about a matter which was brought to my attention by a constituent from South Carolina. The constituent states that the Supreme Court has found laws requiring the wearing of helmets by motorcyclists to be unconstitutional. He does not understand why laws requiring people to wear seat belts in cars would not also be unconstitutional. The constituent poses an interesting question, and I respectfully request that you look into this matter, particularly as it relates to existing federal and state precendents, and furnish me with a reply that I might share with him. Thank you for your cooperation in this matter. I look forward to hearing from you. With kind regards, I am Respectfully |
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ID: nht89-2.33OpenTYPE: INTERPRETATION-NHTSA DATE: 07/12/89 FROM: GEORGE A. VAN STRATEN -- VAN STRATEN HEATED TAIL LIGHT CO TO: STEPHEN P. WOOD -- ACTIVE CHIEF COUNSEL U.S. DEPT. OF TRANSPORTATION NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 08/11/89 FROM STEPHEN P. WOOD -- NHTSA TO GEORGE A. VANSTRATEN; REDBOOK A34; STANDARD 108; LETTER DATED 05/16/89 FROM STEPHEN P. WOOD -- NHTSA TO THOMAS C. GRAVENGOOD -- AGAPE PLASTICS TEXT: Dear Mr. Wood: I am writing to you in regard to the product which I have invented and received patents on, called the "Heated Tail Light". I developed this product to keep the tail lights on vehicles snow and ice free in the winter months, so signals are clearly visib le. Recently my wife Jill spoke over the telephone with Mr. Benson from your department, who said you could help with my problem and I should send this information to your attention. We have been working with our State Representatives office in Lansing, Michigan and through them a company by the name of Agap'e Plastics, Inc. from Grand Rapids, Michigan had heard of my product. A gentleman by the name of Tom Gravengood from Agap'e ap proached me about buying my company. He said that he wanted to help me out with sending my product into your department, as he already had the right connections and it would surely speed things up. Now, with my sending Mr. Gravengood the sample "Heated Tail Lights" and customer letters we had received, along with other information, we were under the understanding that this was to be handled under my company name. Also, I was to receive copies of any correspondence from your office. After quite some time, Mr. Gravengood finally told me over the telephone that he did receive a letter from you and he was reading parts of the letter to me. I could tell that the letter was to him and not to my company. After repeatedly trying to receive a copy of the letter, it was finally sent to me, however, not by Mr. Gravengood, but by our State Representatives office. It was sometime in the middle of June when I received it. I have enclosed a copy of the letter for you. What I would greatly appreciate is, if you would send me a copy of any incoming correspondence from Mr. Gravengood and also, a letter in duplicate to the one sent to Mr. Gravengood dated May 16, 1989, but addressed to myself and my company. With receivi ng interest at the O.E.M. level, customers do indeed want to see some proof that I have gone through your office. With this, I can show them that I have done so. I have enclosed some information on the "Heated Tail Light" to familiarize you with the product again. If you have any questions about anything, please feel free to give me a call at either (906) 353-7131 or (906) 353-6490. Thank you very much. Sincerely, |
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ID: nht89-2.34OpenTYPE: Interpretation-NHTSA DATE: July 14, 1989 FROM: J. Michael Mundy -- Lease Sales Representative, Penske Truck Leasing Co., L.P. TO: Emory Lariscy TITLE: None ATTACHMT: Attached to letter dated 9-4-90 from P.J. Rice to E.J. Lariscy (A36; Std. 108; Std. 124; Std. 301); Also attached to letter dated 8-28-89 from E.L. Lariscy to G. Shifflett (OCC 3910) with Patent Application for Vehicle Safety Light Assembly (gr aphics omitted); Also attached to letter dated 7-14-89 from J.M. Staples to E.L. Lariscy; Also attached to letter dated 8-8-89 from L. Baer to E.L. Lariscy; Also attached to letter dated 7-28-89 from A.M. Kennedy to E.L. Lariscy TEXT: I recently had the opportunity to witness your speed-caution light in operation. It is a truly effective piece of safety equipment. Rear end collisions are especially prevalent in the transportation industry because of lower speeds required due to weight and product requirements. This light would not only save money in reduced repair cost and lower insurance premiums. More importantly, it may save someone's life. Please forward me any information possible on your product as it becomes available. |
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ID: nht89-2.35OpenTYPE: Interpretation-NHTSA DATE: July 14, 1989 FROM: James M. Staples -- Director of Safety and Health, Bassett- Walker, Inc. TO: Emory L. Lariscy -- President, Lariscy Enterprises, Inc. TITLE: None ATTACHMT: Attached to letter dated 9-4-90 from P.J. Rice to E.J. Lariscy (A36; Std. 108; Std. 124; Std. 301); Also attached to letter dated 8-28-89 from E.L. Lariscy to G. Shifflett (OCC 3910) with Patent Application for Vehicle Safety Lighty Assembly (g raphics omitted); Also attached to letter dated 7-14-89 from J.M. Mundy to E. Lariscy; Also attached to letter dated 8-8-89 from L. Baer to E.L. Lariscy; Also attached to letter dated 7-28-89 from A.M. Kennedy to E.L. Lariscy TEXT: Several days ago, I had the opportunity to observe a vehicle that had a safety caution light installed in the rear window over the third brake light. As I was following this vehicle, I noticed this caution light would operate independently of the brake lighting system which alerted me that something was occurring with the vehicle ahead of me. This raised my awareness and when the vehicle, ahead of me with the caution light installed, began to decelerate and stop, to my surprise, I was able to react and began to brake before the brake lights came on indicating that the vehicle ahead was attemp ting to stop. An inquiry into this device has led me to write you and express my feelings from this experience. I was employed as a Police Officer for the City of Martinsville for 10 years and worked as a Traffic Officer five of those ten years, and during that time, I investigated many automobile accidents. I am now employed by Bassett-Walker, Inc. as Director o f Safety and Health, and have been in this capacity for the past eight years. From both of these positions, I can clearly see that if this device had been installed on vehicles, a large amount of the accidents which involved rear-end collisions could have been prevented. I certainly hope you will consider manufacturing and marketing this safety caution light because it is my opinion that this small device is a giant step in accident prevention which will save lives, reduce over all cost for insurance, property damage and bodily injury. |
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ID: nht89-2.36OpenTYPE: INTERPRETATION-NHTSA DATE: 07/19/89 FROM: THEO BOSE -- WEBASTO HEATER INC TO: FEDERAL HIGHWAY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 05/31/90 FROM STEPHEN P. WOOD -- NHTSA TO THEO BOSE -- WEBASTER HEATER INC, A35, STD 301 TEXT: We are a improter and distributor of diesel fuel burning coolant heaters and air heaters for automotive applications. These units are often installed in busses or trucks to preheat the engine and/or provide supplementary heat to busses and school busses etc. We are often asked by OEM's to certify the unit as required under the above mentioned paragraph or to FMVSS 301-75. Fuel intergrity and safety are of high importance to us and we would like your comments about this subject to be able to furnish the proper documentation to our customer clientele. I have enclosed one typical installation manual for your review. Your earliest response is appreciated. Contact me if you have any questions. encl: DBW 2020 manual |
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ID: nht89-2.37OpenTYPE: INTERPRETATION-NHTSA DATE: July 20, 1989 FROM: Kathleen DeMeter -- Assistant Chief Counsel for General Law, NHTSA TO: B.L. Swank -- Swank-Standley Motors, Inc. (Kansas) TITLE: NONE ATTACHMT: ATTACHED TO 11/28/95 LETTER FROM Samuel J. Dubbin to Phyllis Armstrong (A43; Part 580); Also attached to 5/17/95 letter from Phyllis Armstrong to Phillip Reckt TEXT: Dear Mr. Swank: This is in response to your letter of May 31, 1989, requesting an interpretation of the Federal odometer disclosure requirements. You asked how someone who had disconnected the odometer of his or her vehicle in order to tow the vehicle would complete an odometer disclosure statement upon that vehicle's transfer. As long as the drive wheels are removed from the pavement, the distance travelled by a vehicle in tow need not be counted, and the transferor of such a vehicle need not certify that the odometer reading does not reflect that vehicle's actual mileage. Ho wever, a vehicle towed with the drive wheels running on the pavement would be considered to have travelled the distance it had been towed. Thus, because of the increased wear to the vehicle in that situation, the transferor of such a vehicle would have to declare that the odometer reading did not reflect the vehicle's actual mileage. It should, of course, be remembered that anyone who has towed a vehicle must reconnect the vehicle's odometer before next driving the vehicle, the operation of a vehicle whiel its odometer is disconnected is a violation of Federal law. Thank you for your interest in the Federal odometer disclosure requirements. If you have any further questions, please do not hesitate to contact Mattie Cohan of my staff at (202) 366-1834. Sincerely |
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ID: nht89-2.38OpenTYPE: INTERPRETATION-NHTSA DATE: 07/21/89 FROM: STEPHEN P. WOOD -- NHTSA TO: Anonymous (confidential) TITLE: NONE TEXT: Dear This is in reply to your letter of June 30, 1989, to John Donaldson of this Office titled "Request for Interpretation", submitted on behalf of your client. You request "that all identifying references to myself, my firm and [my client] in this letter and the responsive letter of interpretation" be deleted. Your request is granted on the basis that it relates to confidential business information and may be withheld under applicable Departmental regulations, 49 CFR Part 512. You describe a lamp system as follows: "The product is a headlamp consisting of a plastic lens and reflector, arc tubes (two each for high and low beam) and electronics for instant start and re-start of the headlamps as well as management of the operating current. A 12 volt connection is supplied for connection of vehicle line voltage". You have asked for a letter "confirming" that this lamp system is designed to conform to the integral beam headlamp requirements of paragraph S7.4 of Federal Motor Vehicle Safety Standard No. 108, "subject only to compliance with the appropriate photomet ric requirements of FMVSS 108." A headlighting system of the nature described must be designed to conform to all the pertinent requirements of S5.5, S7.1, S7.2, and S7.7, as well as S7.4, including mechanical aim and environmental requirements. However, since this headlamp does not us e filaments for converting the electrical energy to light energy, certain configurations of such systems may not conform, because some requirements are predicated upon the existence of filaments (e.g., S5.5.9 and S7.4(f)). If the headlamp you describe m eets all requirements, then it would appear to be an integral beam headlighting system designed to conform to S7.4. Whether the headlamp in fact meets those requirements is for the lamp manufacturer to determine, as it must assure the manufacturer of the vehicle on which it 2 is installed that he may certify compliance of the vehicle with Standard No. 108. Further, the headlamp manufacturer itself must certify compliance of replacement equipment. If the headlamp is incompatible with these requirements and cannot meet them, then it would not appear to be an integral beam system. In that case, rulemaking would be required to accommodate it within the framework of Standard No. 108. Sincerely, |
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ID: nht89-2.39OpenTYPE: INTERPRETATION-NHTSA DATE: 07/21/89 FROM: RICHARD L. VAN IDERSTINE -- SAFETY STANDARDS ENGINEER, NHTSA TO: DOCKET SECTION; THRU: RALPH HITCHCOCK, DIRECTOR -- OFFICE OF VEHICLE SAFETY STANDARDS; VIA: OFFICE OF CHIEF COUNSEL TITLE: ACTION: SUBMISSION TO DOCKET 85-13, NOTICE 7 AND NOTICE 8, OF A CONGRESSIONAL INQUIRY AND NHTSA'S RESPONSE CONCERNING ULTRAVIOLET EMISSIONS FROM HEADLAMPS ATTACHMT: ATTACHED TO LETTER DATED 3-15-90 TO T. CHIKADA, STANLEY ELECTRIC CO., LTD., FROM STEPHEN P. WOOD, NHTSA; [A35; STD. 108]; ALSO ATTACHED LETTER DATED 8-9-89 TO ERIKA Z. JONES, NHTSA, FROM T. CHIKADA, STANLEY ELECTRIC CO., LTD.; [OCC 3832] TEXT: Please place the attached letters in Docket 85-15; Notice 7 and Notice 8, for Standard No. 108. The attachments concern the potential for ultraviolet light emissions from future headlighting systems such as those using a high intensity discharge, gaseou s discharge, or short arc metal-halide light sources. Attachment (w/10 copies) |
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ID: nht89-2.4OpenTYPE: INTERPRETATION-NHTSA DATE: 06/16/89 EST FROM: BARRY FELRICE -- NHTSA ASSOCIATE ADMINISTRATOR FOR RULEMAKING TO: EDWARD P. KIRBY -- MASSACHUSETTS SENATE TITLE: NONE ATTACHMT: LETTER DATED 04/11/89 FROM EDWARD P. KIRBY TO BARRY FELRICHE -- NHTSA TEXT: Dear Senator Kirby: Thank you for your recent letter enclosing Senate Bill No. 1217 which you have filed in the Massachusetts General Court, and which has been referred to the Committee for Public Safety. Your bill would require all new motor vehicles made or sold in Massa chusetts to have amber-colored directional signals as of January 1, 1990. Your comment that "such matters are reserved for the Federal government" is essentially correct. The express preemption provisions of the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1392(d), permit States to have motor vehicle safety standa rds regulating the same aspects of performance as Federal standards provided that the State requirements regarding those aspects are identical to the Federal ones. In instances in which the Federal government has no standard (for example, there are none covering such equipment as horns or fog lamps), a State may have its own standard. As to the subject at hand, 49 C.F.R. 571.108 Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment, prescribes requirements f or the color of motor vehicle turn signals. At the front, they must be amber, and at the rear, either amber or red. Thus, if Senate Bill No. 1217 were enacted, it would be preempted under the Vehicle Safety Act to the extent that it required rear turn signals to be amber. Years ago, in an attempt to standardize rear lighting, the agency proposed to eliminate the choice regarding the color of turn signals and to pick one of the two permissible colors and mandate its use. Because there were no clear benefits either way, an d because manufacturers wished to continue their existing practice (in general, the domestics preferred red, and the others, amber), the agency terminated rulemaking. Informal agency studies since then have been similarly inconclusive. NHTSA has always been interested in improving the effectiveness of rear lighting and its present efforts are devoted to the general area of lamp size, separation, and color, of which t urn signal color is a part. However, because no data exist to support a requirement that only amber 2 be used for rear turn signals, there are no present plans to propose an amendment to Standard No. 108 that would eliminate red as a color choice. We appreciate your interest in turn signal effectiveness, and ask that this letter be considered by the Committee of Public Safety in its deliberations. We would find it helpful if you would send us any data submitted to the Committee relating to the re lative merits of amber and red rear turn signals. Sincerely, |
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.