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: nht72-1.33OpenDATE: 06/27/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Checker Motors Sales Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 25, 1972, asking whether you, as a selling dealer, may install steel-belted radial ply tires on an 8-passenger Checker taxicab. You state that the vehicle is normally delivered to you with tires having the "D" load range. Federal Motor Vehicle Safety Standard No. 110 (49 CFR 571.110, copy enclosed) requires each passenger car to be equipped at the time of sale to a first purchaser with tires of 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 or 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 installed on these vehicles without adversely affecting the vehicle's conformity with Motor Vehicle Safety Standard No. 110. |
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ID: nht92-5.4OpenDATE: July 31, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Le Van Lac -- Vice President, Pioneer Electronic Services, Inc. TITLE: None ATTACHMT: Attached to letter dated 6/5/92 from Le Van Lac to Paul J. Rice (OCC 7406) TEXT: This responds to your letter of June 5, 1992, with reference to your plan to sell a new car speaker in the U.S. It will be installed "in the rear deck" with the "Pioneer brand name to be printed on the rear side of the speaker cabinet." The brand name will be lit "with blue color at night" and "there are 8 lamps for each left and right speaker." The brightness of the lamp is "just 1/40 of the high mount stop lamp." You believe that the "illuminated speaker will not impair the effectiveness of the existing lighting equipment installed into the car." We understand that the speaker will be sold as aftermarket equipment, not as original equipment. Installation of the speaker by a manufacturer, distributor, dealer, or motor vehicle repair business is permissible under the National Traffic and Motor Vehicle Safety Act as long as it does not render inoperative, in whole or in part, any of the rear view mirror or lighting equipment that is required by Federal Motor Vehicle Safety Standard No. 108. The drawing you enclosed, and the description of the speaker, are insufficient for us to provide you a definitive interpretation. For instance, it is not possible to tell whether the light is oriented to the rear, so that it will be seen through the rear window, adjacent to the center highmounted stop lamp, or whether it is oriented to the front, so that it will reflect in the rear view mirror. In either location, it may have the potential to affect negatively the safety performance of rear view mirrors or the rear center stop lamp. Taylor Vinson of this Office telephoned your company on June 22, suggesting that it furnish a clearer drawing and a better description. As of the date of this response, we have heard nothing further from you. Further, there are state laws that prohibit illumination in vehicle interiors under certain conditions. We are unable to advise you of these laws. The American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203, may be able to provide you with an interpretation. |
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ID: nht74-5.32OpenDATE: 04/12/74 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Chrysler Corporation TITLE: FMVSS INTERPRETATION TEXT: This responds to your March 13, 1974, request for confirmation that the intake manifold connector and the brake booster check valve used in connecting the engine intake manifold and the vacuum power brake booster are not subject to Standard 106, Brake hoses. A brake hose end fitting is defined in Standard 106 as "a coupler, other than a clamp, designed for attachment to the end of a brake hose." As pictured in your schematic, the couplers are the clamps, and the intake manifold connection and brake booster check valve are engine components to which the brake hose has been attached by the clamp couplers. Therefore your interpretation is correct that neither component is subject to Standard 106. SINCERELY, March 13, 1977 Elwood T. Driver Director, Office of Operating Systems National Highway Traffic Safety Administration Re: Docket 1-5; Notice 10 Amendment to MVSS 106 Brake Hoses Chrysler Corporation requests confirmation of the informal interpretation provided to us by a member of your staff concerning the recently amended requirements of MVSS 106 (39 F.R. 7435) as they apply to the hook-up between the engine intake manifold and the vacuum power brake booster. To make this hook-up one end of a section of vacuum brake hose is slipped onto the intake manifold connector and the other end is slipped onto the brake booster check valve as shown in the attached schematic of this system. The hose is held secure at each end by a spring type hose clamp. In accordance with that conversation it is our understanding that the vacuum hose used to connect the intake manifold to brake booster is a brake hose within the meaning of the standard. However, since this hose is secured by clamps, it is not a brake hose assembly under the standard and, therefore, the intake manifold connector and the brake booster check valve are not subject to the requirements of MVSS 106. This is in keeping with the amendment to the definition of brake hose assembly deleting the reference to "clamps." In view of the short time period allowed for compliance with the new requirements, prompt confirmation of our interpretation is requested. R. O. Sornson Manager Environmental and Safety Relations (Graphics omitted) BRAKE BOOSTER CHECK VALVE VAC BRAKE HOSE VAC HOSE CLAMP INTAKE MANIFOLD CONNECTOR ENGINE MANIFOLD |
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ID: 20836.ztvOpenMr. Shigeyoshi Aihara Dear Mr. Aihara: This is in reply to your letter of October 21, 1999, asking for an interpretation of Standard No. 108's requirements for visibility of front turn signals. You have made this request for a specific design which you have enclosed. I am sorry that our reply has been delayed. This design depicts a lamp assembly containing a headlamp and a turn signal lamp. The assembly has a transparent lens. The turn signal lamp has a separate amber lens inside the assembly. Standard No. 108 requires that "to be considered visible, the lamp must provide an unobstructed view of the outer lens surface, excluding reflex reflectors, of at least 12.5 square cm measured at 45 deg. to the longitudinal axis of the vehicle." (paragraph 5.4.1 of SAE Standard J588 NOV84 incorporated by reference in Standard No. 108). Your question, in essence, is whether the "outer lens surface" is the surface of the amber lens of the turn signal lamp alone, or that portion of the surface of the transparent lens of the entire lamp assembly that is in front of the amber lens of the turn signal lamp. The drawing you furnished identifies the "unobstructed view area" measured at the 45 deg. observation angle with respect to the amber lens alone as " C." The "unobstructed view area" measured at the 45 deg. observation angle with respect to the amber lens projected on the transparent lens in front of it is identified as "B." The area of "B" is much larger than the area of "C." You have asked for confirmation that the transparent lens surface may be regarded as the "outer lens surface" and that unobstructed view area "B" is acceptable under Standard No. 108. I regret that we cannot confirm your interpretation. It is clear to us that the term "outer lens surface" as used in SAE's and NHTSA's turn signal lamp standard, SAE Standard J588 NOV84, for the purpose of observable lens area of a signal lamp, means the lens of the turn signal lamp itself. When the turn signal lamp is part of a larger assembly with a separate lens, the term"outer lens surface" continues to mean the lens surface of the turn signal lamp, the lamp that is actually providing the light, without reference to the surface of the lens of the larger lamp assembly. Thus, area "C" is the area that must meet the visibility requirements. Sincerely, |
2000 |
ID: nht76-5.15OpenDATE: 11/10/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Triplex Safety Glass Co. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your September 8, 1976, letter requesting information concerning the Federal regulations that would be applicable to safety glazing for use in "slow moving" vehicles. Please excuse our delay in answering your questions. Apparently, your earlier letter of February 5, 1976, was misplaced. Standard No. 205, Glazing Materials, specifies requirements for glazing materials for use in most motor vehicles and motor vehicle equipment. A glazing manufacturer must certify any glazing that is to be used in a motor vehicle (other than a trailer) as being in compliance with Standard No. 205. "Motor vehicle" is defined in @ 102(3) of the National Traffic and Motor Vehicle Safety Act of 1966. I am enclosing a copy of the agency's opinion of what vehicles qualify as "motor vehicles" under the definition. Glazing material that is to be used in a vehicle that does not qualify as a "motor vehicle" does not have to meet the performance requirements of Standard No. 205. Sincerely, Enclosure ATTACH. SEPTEMBER 8, 1976 Triplex Safety Glass Co Ltd Robert L. Carter -- Associate Administrator, Motor Vehicle Programs, U.S. Department of Transportation, National Highway Traffic Safety Administration, Dear Mr. Carter, On 5th February 1976 I wrote to the Department of Transportation requesting information on possible regulations in the U.S.A. governing the safety glazing to be fitted in slow moving vehicles. To date I have not received a reply. It may be that the letter was lost in the post and I, therefore, enclose a copy. I realise, of course, that this query is probably nothing to do with your department, but I would be grateful if you could either forward it to the correct authority or alternatively let us have the address of this authority in order that we can write to them ourselves. Yours sincerely, MISS VALERIE HOOD -- Standards Department FEBRUARY 5, 1976 The Administrator -- National Highway Traffic Safety Administration, U.S. Department of Transportation, Dear Sir, SLOW MOVING VEHICLES Can you please let us know what regulations, if any, govern the type of safety glazing which must be fitted in slow moving vehicles (i.e. vehicles with a maximum speed of 20-25 km/h) in the U.S.A. These vehicles are usually agricultural or forestry vehicles, etc. which might go on a public road for short periods. Our understanding of U.S. National Traffic and Motor Vehicle Safety Act 1966 and F.M.V.S.S. 205 are that neither covers such vehicles. The former describes a motor vehicle as "any vehicle driven or drawn by mechanical power manufactured primarily for use on public streets, roads and highways" and the latter applies only to passenger cars, multi-purpose passenger vehicles, trucks, buses, motor cycles, slide-in campers and pick up covers. If the above query does not come within your jurisdiction, we would be grateful if you would forward our letter to the correct authority. Yours faithfully, TRIPLEX SAFETY GLASS COMPANY LIMITED; MISS VALERIE HOOD -- Standards Department |
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ID: nht94-3.80OpenTYPE: INTERPRETATION-NHTSA DATE: July 25, 1994 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: William R. Willen, Esq. -- Managing Counsel, American Honda Motor Co., Inc., TITLE: None ATTACHMT: Attachment dated 6/28/94 Letter from William R. Willen to administrator, NHTSA (6335) TEXT: We have received your "Petition for Honda Electric Vehicles in accordance with FMVSS @ 555.6(c)" (correctly, 49 CFR @ 555.6(c)), dated June 28, 1994. The petition is incomplete in certain respects. It fails to provide the public interest and traffic safety arguments required by @ 555.5(b)(7). Section 555.6(c)(2)(iii) requires the submission of "the results of any tests conducted on the vehicle that demonstrate its failure to meet the standard, expressed as comparative performance levels." You have provided this information with respect to your request for exemption from Standard No. 103 but not with respect to the eight interior components that acc ompany your request for exemption from Standard No. 302. If you have conducted tests on these components, you are required to submit them as part of your petition. In addition, the petition does not state whether the period for which exemption is requested is for one or two years (you may need the latter if the manufacture of the 20 electric vehicles is not completed within a year from the date of grant of the peti tion). If the vehicles are manufactured outside the United States, Honda may wish to avail itself of the provisions of 49 CFR 591.5(j) which allows a manufacturer to import noncomplying vehicles for purposes of research, investigation, and studies for a period of up to three years (when the temporary importation bond must be paid). After payment of the bond, a manufacturer may request NHTSA for an extension if it requires further time to complete its tests and evaluations. We shall hold your petition in abeyance until we hear further from you. |
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ID: 6335Open William R. Willen, Esq. Dear Mr. Willen: We have received your "Petition for Honda Electric Vehicles in accordance with FMVSS '555.6(c)" (correctly, 49 CFR '555.6(c)), dated June 28, 1994. The petition is incomplete in certain respects. It fails to provide the public interest and traffic safety arguments required by '555.5(b)(7). Section 555.6(c)(2)(iii) requires the submission of "the results of any tests conducted on the vehicle that demonstrate its failure to meet the standard, expressed as comparative performance levels." You have provided this information with respect to your request for exemption from Standard No. 103 but not with respect to the eight interior components that accompany your request for exemption from Standard No. 302. If you have conducted tests on these components, yuou are required to submit them as part of your petition. In addition, the petition does not state whether the period for which exemption is requested is for one or two years (you may need the latter if the manufacture of the 20 electric vehicles is not completed within a year from the date of grant of the petition). If the vehicles are manufactured outside the United States, Honda may wish to avail itself of the provisions of 49 CFR 591.5(j) which allows a manufacturer to import noncomplying vehicles for purposes of research, investigation, and studies for a period of up to three years (when the temporary importation bond must be paid). After payment of the bond, a manufacturer may request NHTSA for an extension if it requires further time to complete its tests and evaluations. We shall hold your petition in abeyance until we hear further from you. Sincerely,
John Womack Acting Chief Counsel ref:555#591 d:7/25/94
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1994 |
ID: 16867.ztvOpenMr. Clarence Ogrodnick Dear Mr. Ogrodnick: This is in reply to your fax sent to us on January 6, 1998. Your company manufactures "an after market product in North America . . . a hydraulic power deck made to load and unload cargo such as snowmobiles . . . ." The deck "mounts into the box on all makes of regular shortbox and longbox pick up trucks." You wish to ensure that it meets U.S. Federal regulations "as to width, height, length, and light location specifications" so that you can be certain that your product "is safe and legal everywhere." There are no U.S. Federal regulations that govern the width, height, and length of your after market hydraulic power deck. Furthermore, as a general rule, the laws that govern the use of after market equipment are those of the individual States, rather than Federal law. As we are not conversant with the laws of the States, I am afraid we cannot advise you on them. If the hydraulic power deck is added to the pickup truck by a "manufacturer, distributor, dealer, or motor vehicle repair business," under our law this modification must not create a noncompliance with Federal lighting requirements (or any other Federal motor vehicle safety standard with which the truck was manufactured to conform). Removal or obscuration of the lamp are the two principal ways in which noncompliances are created. The addition of a supplementary lamp performing the function of the original in approximately the same location is a way of ensuring that original equipment requirements continue to be met. Note that this compliance restriction applies only to the four entities named, and not to a vehicle owner who installs a power deck without the assistance of a "manufacturer, dealer, distributor or motor vehicle repair business." If you have any questions, you may refer them to Taylor Vinson of this Office (202-366-5263). Sincerely, |
1998 |
ID: nht75-3.24OpenDATE: 05/16/75 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: P. H. Plastics Inc. TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of April 11, 1975, requesting information concerning the registration of certain vehicle types and laws relating to maximum length, width, and weight of vehicles. It is unclear from your letter what you mean by "registration certificate." The National Traffic and Motor Vehicle Safety Act (Pub. L. 89-563) requires that all vehicles used on United States highways be certified by their manufacturer as complying with all applicable Federal motor vehicle safety standards. 49 CFR Part 567 and 568 specify the manner in which this certification must be accomplished. If by "registration certificate" you are referring to the necessary licensing of a vehicle for operation on United States roadways, I suggest you contact the States in which you would be operating your vehicles for the answers to your questions. The questions you ask relating to "special licenses" for 3-axle vans and transportation of your own raw materials and products are also unclear. As I stated above, NHTSA regulations only require that you certify the compliance of your vehicles with all applicable motor vehicle safety standards. We do not limit the type of products that may be imported into this country. With regard to your question concerning maximum limitations on trailer and van length, width, and weight, this agency has no regulations which restrict the size of vehicles. As long as they meet the performance criteria established in our various safety standards, they have satisfied the provisions of the Traffic Safety Act. States generally have a limitation on the size of vehicles that operate on their roadways. Therefore, for this reason also, I suggest that you contact the States whose laws might affect the use of your vehicles within the United States. |
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ID: GF006332OpenMr. Timothy C. Murphy Dear Mr. Murphy: This responds to your letter dated August 18, 2004, asking whether strobing stop lamps or auxiliary lamps are permissible under the requirements of Federal motor vehicle safety standard (FMVSS) No. 108. By way of background, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. The issues raised by your letter are addressed below. The Federal standard applicable to lighting equipment, including stop lamps, is FMVSS No. 108, Lamps, Reflective Devices and Associated Equipment. The relevant sections of that standard read as follows:
In short, S5.5.10(d) of FMVSS No. 108 mandates that all lamps be steady burning, unless otherwise explicitly permitted.In the present case, stop lamps do not fall under any exception enumerated in S5.5.10 (a) through (c).Accordingly, FMVSS No. 108 requires stop lamps to be steady burning. We regard a strobe lamp as one that flashes. For this reason, the strobing stop lamps described in your letter would be prohibited by FMVSS No. 108, if they are installed as original equipment on motor vehicles.They would also be prohibited from being sold as replacement for original equipment stop lamps.Further, unless auxiliary lamps mentioned in your letter fall under any exception enumerated in S5.5.10 (a) through (c), they must also be steady burning. This prohibition would also apply to aftermarket lighting installation because 49 U.S.C. 30122 prohibits manufacturers, dealers, distributors, and motor vehicle repair businesses from making inoperative safety equipment installed in accordance with FMVSS No. 108 (and any other applicable FMVSS as well).Accordingly, installation of a strobing lamp not permitted by S5.5.10 would create a noncompliance with FMVSS No. 108 which constitutes "making inoperative" within the meaning of the statute. The list of persons prohibited from making vehicle modifications affecting compliance in 49 U.S.C. 30122 does not include vehicle owners. I hope you find this information helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman ref:108 |
2004 |
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.