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: aiam2483OpenMr. David J. Humphreys, 5272 River Road, Suite 400, Washington, D.C. 20016; Mr. David J. Humphreys 5272 River Road Suite 400 Washington D.C. 20016; Dear Mr. Humphreys: This responds to your November 24, 1976, letter in which you as whether a draft certification label and owner's manual (submitted along with your letter) that are designed to accompany a camper would comply with Standard No. 126, *Truck-Camper Loading*.; The camper you describe uses a third axle which can support varyin amounts of the 'total cargo weight' of the caper, as this term is used in the standard. Although this camper falls within the definition of a slide-in camper, the NHTSA concludes that the requirements of Standard No. 126 are not appropriate and were not intended for this type of camper. Campers employing third axles as part of their support pose loading problems which Standard No. 126 does not adequately address. The required statements and figures in S5.1.2(c) and (e) of the standard address the concept of 'center of gravity' not 'effective center of gravity' to which you refer in your letter.; Although we have interpreted the requirements of Standard No. 126 to b inappropriate and inapplicable to the camper you describe, we recognize a need to provide the purchaser with sufficient information to ensure that the load capabilities of trucks will not be exceeded and that the 'effective center of gravity' of the camper will correspond to the center of gravity of the truck. The information detailed in your letter should aid the purchaser in the safe installation of the camper. Without this information improper installation could more easily occur, which would affect the overall safety of the vehicle.; At this time, we are not able to make ny comments regarding potentia handling problems that may arise because of the additional axle. The NHTSA will, therefore, continue to study the use of campers with third axles. If the agency identifies problems in this configuration or discovers accidents resulting from improper installation of the camper, we would consider amending Standard No. 126 to include appropriate requirements for campers with third axles.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0514OpenMr. Armand F Macmanus, Esq., Phillips Petroleum Company, Bartlesville, Oklahoma 74004; Mr. Armand F Macmanus Esq. Phillips Petroleum Company Bartlesville Oklahoma 74004; Dear Mr. Macmanus: This is in reply to a request made on behalf of Phillips Petroleu Company by Veigh J. Nielson for an assigned identification mark for two of Phillips' plants which manufacture tires for research purposes.; As I informed you in my letter of September 20, 1971, if Phillip purchases a new tire, removed the tread material an then applies its own experimental tread containing various rubber compounds, Phillips is considered to be a new tire manufacturer. If Phillips applies its experimental tread to a used tire, it is considered a retreader of tires.; As a new tire manufacturer you are required to certify the tire a conforming to the new passenger car tire standard (No. 109) and comply with Part 574 - Tire Identification and Record Keeping (49 CFR 574). Accordingly, you are assigned the identification mark of 'J1' for tires made in your Bartlesville, Oklahoma plant and 'K1' for tires manufactured in you Stow, Ohio plant.; If you act as a retreader then Part 574 would not be applicable for th tires you retread because they are retreaded for your own use. (Enclosed is a copy of Docket No. 70-12, Notice No. 8 which makes the regulation inapplicable to retreaders who retread for their own use). As explained in my letter of September 20, you are, of course, required to certify that your new tires and your retreaded tires comply with the respective standards for new and retreaded tires if they are to be used on public highways, by placing the symbol DOT on the tires in the prescribed location.; Sincerely, Lawrence R. Schneider |
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ID: aiam2529OpenMr. Edmund C. Burnett, Paulson and Humphreys, Suite 400, 5272 River Road, Washington DC 20016; Mr. Edmund C. Burnett Paulson and Humphreys Suite 400 5272 River Road Washington DC 20016; Dear Mr. Burnett: This responds to your February 3, 1977, letter asking whether th intersection of a plywood floor panel and the floor channel structure constitutes a 'body panel joint' subject to the requirements of Standard No. 221, *School Bus Body Joint Strength*.; The terms which establish the applicability of the requirements of th standard to a particular section of a school bus body are defined in S4 of the standard. Read together, they establish the following test. If the edge of a surface component (body panel) that encloses the bus' occupant space comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose or is a door, window, or maintenance access panel. Applying this test to the joint your describe, it appears that the joint must comply with the requirements of the standard, because it is the connection of a body component (floor channel structure) with a body panel that encloses occupant space (plywood floor panel).; In youe letter, you argue that the standard is not directed at thes types of joints and that in fact the NHTSA stated that not all joints would be regulated by this standard. While it is true that not all joints are regulated by the standard, all joints between the edge of a body panel and a body component are regulated unless expressly excepted from coverage by the language of the standaard itself. Since the joint you describe connects a body panel to a body component, it is exactly the type of joint for which coverage was intended.; Finally, you argue that all joints located below the floow are no covered by the standard. This is correct. However, the NHTSA has required floor panels regardless of composition to comply with the requirements of the standard, since these panels form the floor and do not fall below it.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4804OpenMr. Dean J. Long Design Engineer VDO-YAZAKI Corporation l773 Star-Batt Drive Rochester Hills, MI 48309; Mr. Dean J. Long Design Engineer VDO-YAZAKI Corporation l773 Star-Batt Drive Rochester Hills MI 48309; "Dear Mr. Long: This responds to your letter asking about requirement concerning two proposed automotive instrument panel telltale warnings. I apologize for the delay in this response. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its motor vehicles or equipment comply with applicable safety standards. The following represents our opinion based on the facts provided in your letter. Your first proposed telltale design is for '4 wheel antilock brake application.' The design would include a picture of a skidding car and the letters '4W ABS.' You asked whether this telltale would fulfill applicable requirements or whether the ISO 'ABS' symbol must be used. Standard No. l0l, Controls and Displays, requires that new vehicles with any display listed in the standard must meet specified requirements for the location, identification and illumination of such display. In addition, certain other standards, including Standard No. l05, Hydraulic Brake Systems, include requirements relating to vehicle displays. Standards No. l0l and No. l05 include several requirements for telltales indicating malfunction in an antilock brake system. Copies of these standards are enclosed for your convenience. Among other things, these standards specify the following identifying words or abbreviation for an antilock malfunction telltale: 'Antilock, Anti-lock or ABS.' The standards also permit additional words or symbols to be used for the purpose of clarity. See section S5.2.3 of Standard No. l0l and section S5.3.5(a) of Standard No. l05. It is unclear from your letter whether your proposed telltale would indicate 'malfunction' in an antilock brake system, since you describe it as indicating '4 wheel antilock brake application.' If the telltale is for antilock malfunction, it would appear to meet the requirements specified in Standards No. l0l and No. l05 for identifying words or symbols, since it includes the abbreviation 'ABS,' and the other words/symbols can be considered to be for the purpose of clarity. Of course, the telltale would also need to meet the other requirements specified in those standards, e.g., size of letters, color, etc. If the telltale does not indicate antilock malfunction, e.g., it only indicates when the antilock system is activated during braking, no requirements would apply to the telltale. Unless a particular telltale is listed in Standard No. l0l (or is covered by another standard), no requirements apply to such telltale. If the telltale does not indicate antilock malfunction, however, I would suggest that you consider whether drivers would confuse the telltale with the required telltale for antilock malfunction. Your second proposed telltale is for warning against hazardous emissions from the vehicle. Your design would include an outline of an engine and the word 'CHECK.' You asked whether the word 'CHECK' is necessary, and whether the engine outline is an approved ISO symbol. NHTSA does not have any requirements for a telltale warning against hazardous emissions from the vehicle. However, we suggest that you check with the Environmental Protection Agency and the California Air Resources Board as to whether they have any requirements (or are developing requirements) concerning such a telltale. You may contact those agencies at the following addresses: Environmental Protection Agency Office of Mobile Sources Certification Branch 2565 Plymouth Road Ann Arbor, Michigan 48l05 Air Resources Board Certification Section 9528 Telstar Avenue El Monte, California 9l73l I hope this information is helpful. Sincerely, Paul Jackson Rice Chief Counsel /Enclosures"; |
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ID: aiam3011OpenMr. Harvey Schock, Jr., Management Consulting in Product Assurances, P. O. Box 430, Haddonfield, NJ 08033; Mr. Harvey Schock Jr. Management Consulting in Product Assurances P. O. Box 430 Haddonfield NJ 08033; Dear Mr. Schock: This responds to your April 9, 1979, letter asking how the agency wil apply the reporting requirements of Part 573, *Defect and Noncompliance Reports*, to equipment manufacturers.; As the agency indicated in the preamble to the final rule, replacemen equipment manufacturers that are required to notify owners and to remedy defective or noncomplying equipment would do so to the best of their abilities. The reporting requirement does not require them to manufacture their equipment so that it is easily identifiable nor does it require them to maintain lists of persons to whom equipment has been sold. Some equipment manufacturers may wish to upgrade their recordkeeping and identification systems to facilitate their statutory obligations to recall and remedy, but the reporting regulation does not require this.; With respect to the 'flasher' incident to which you refer in you letter, if a vehicle manufacturer authorizes the use of incorrect flashers in its vehicles, problems resulting from the use of those flashers would be the responsibility of the vehicle manufacturer not the equipment manufacturer. The problem that you describe is one of incorrect use of properly functioning equipment. It is not a problem of defective equipment.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3441OpenBrian T. Williams, Esq., Assistant Counsel, Saunders Leasing System, Inc., 201 Office Park Drive, Birmingham, AL 35233; Brian T. Williams Esq. Assistant Counsel Saunders Leasing System Inc. 201 Office Park Drive Birmingham AL 35233; Dear Mr. Williams: This responds to your recent request for an interpretation of ou requirements concerning the presence of a 'DOT' symbol on retreaded truck tires. Specifically, you asked whether a retreader would be in violation of any regulations if the retreader purchases casings (use tires to be retreaded) from which the 'DOT' symbol has already been removed, and whether the retreader itself has a duty to remove the 'DOT' symbol.; The retreader is not liable for using casings from which the 'DOT symbol has been removed, although any manufacturer, distributor, dealer, or motor vehicle repair business other than a retreader which removes that symbol from the casings is violating Federal regulations. The retreader does have an affirmative duty to remove the 'DOT' symbol from the sidewall of retreaded truck tires.; The 'DOT' symbol is required to appear on new truck tires as certification that those tires fully comply with all the requirements of Safety Standard No. 119 (49 CFR S571.119), pursuant to the requirement of section S6.5(a) of that standard. Any manufacturer, distributor, dealer, or motor vehicle repair business who removes this symbol would be removing an element of design installed on the tire in compliance with an applicable Federal motor vehicle safety standard. Such removal is expressly prohibited by section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act of 1966, as amended (15 U.S.C. 1397(a)(2)(A)). However, there is no prohibition against subsequent use of these tires for further manufacturing operations, such as retreading. Hence, a retreader using these casings would not subject itself to any liability for violating section 108(a)(2)(A) or any other regulation.; The retreader has an affirmative duty to remove the DOT symbol from th tire during the course of the retreading operation. Part 574, *Tire Identification and Recordkeeping* (copy enclosed) sets forth the basic tire marking requirements for retreaders of truck tires. Section 574.5 imposes two basic duties on truck tire retreaders - (1) the retreader is required to mold or brand a tire identification number into the sidewall of each tire it retreads, except those retreaded solely for the retreader's own use, and (2) the 'DOT' symbol shall not appear on tires to which no Federal motor vehicle safety standard is applicable. Since there is no safety standard applicable to retreaded truck tires, it follows that no 'DOT' symbol may appear on the sidewall of those tires.; Should you have any further questions or need further information o this matter, feel free to contact me again.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4384OpenMr. Jeffrey A. Crawford, Q.A. Manager, Lyn-Mont Manufacturing Co., P. O. Box 11745, 4208 Clubview Drive, Fort Wayne, Indiana 46860; Mr. Jeffrey A. Crawford Q.A. Manager Lyn-Mont Manufacturing Co. P. O. Box 11745 4208 Clubview Drive Fort Wayne Indiana 46860; Dear Mr. Crawford: This responds to your letter concerning Safety Standard No.. 106 *Brake Hoses*. You asked whether certain proposed labeling for brake hose assemblies would meet the labeling requirements of sections S7.2.3 and S7.2.3.1. As discussed below, the answer to your question is no.; By way of background information, this agency does not provid approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to assure that its products comply with applicable safety standards. The following opinion is based on the facts provided in your letter.; Sections S7.2.3 and S7.2.3.1 provide two options for the labeling o air brake hose assemblies made with end fittings that are attached by crimping or swaging. Section S7.2.3 states that such assemblies, except those assembled and installed by a vehicle manufacturer in vehicles manufactured by him, shall be labeled by means of a band around the brake hose assembly as specified in that paragraph, or, at the option of the manufacturer, by means of labeling as specified in section S7.2.3.1.; If the first option is chosen, using a band as specified in sectio S7.2.3, the band must include (a) the symbol DOT, and (b) the manufacturer designation. If the second option, specified in section S7.2.3.1, is chosen, the manufacturer designation must be placed on at least one end fitting of the assembly. (These sections also specify other requirements concerning labeling, such as size of letters, which are not relevant to this interpretation.); Your proposed labeling, placing the manufacturer designation on th band and the symbol DOT on the end fitting, would not meet the requirements of either of these options. If the first option is chosen, the symbol DOT must be placed on the band along with the manufacturer designation. If the second option is chosen, the manufacturer designation must be placed on the end fitting.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1186OpenMr. Barry Kulik, 114 West 30 Street, New York, NY 10001; Mr. Barry Kulik 114 West 30 Street New York NY 10001; Dear Mr. Kulik: This is in reply to your letter of May 18, 1973, concerning the metho of testing the sensitivity of seat sensors under sections S7.3 and S7.4 of Federal Motor Vehicle Safety Standard No. 208.; The relevant characteristics of the 'person' referred to in thes sections are found in the weight and dimension table of Section S7.1.3 of the standard. Our testing laboratory will, in all likelihood, be using test dummies purchased from the various commercial dummy manufacturers, whose weights and dimensions conform to S7.1.3 of the standard. Human volunteers could be used, but the dimensional controls are difficult to maintain and we do not regard liver (sic) persons as a practical means of testing sensors under the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2600OpenMr. Richard P. Seib, President, United Brake & Clutch, 2100 thru 2116 South Ervay Street, Dallas, TX 75215; Mr. Richard P. Seib President United Brake & Clutch 2100 thru 2116 South Ervay Street Dallas TX 75215; Dear Mr. Seib: This responds to United Brake and Clutch's June 1, 1977, request fo confirmation that use of a brake chamber equipped with separate diaphrams (sic) for application of service brake air pressure and isolated air pressure, along with a mechanical device that automatically holds the brakes in the applied position once they have been applied by means of the protected source of air, would comply with Standard No. 121, *Air Brake Systems*. The relevant provision of the standard states:; >>>S5.6.3 *Application and holding.* The parking brakes shall b applied by an energy source that is not affected by loss of air pressure or brake fluid pressure in the service brake system. Once applied, the parking brakes shall be held in the applied position solely by mechanical means.<<<; The National Highway Traffic Safety Administration is unable t 'approve' system designs for compliance with a standard in advance, because there is no way to establish that a vehicle so equipped actually meets the requirements until it has been manufactured.; From your description, it appears that the design would not violate an provision of the parking brake requirement. Our understanding is that the protected source of air pressure is connected separately to the brake chamber, that it is designed to operate even with failure of the service brake chamber diaphram (sic), and that the mechanical holding device operates automatically whenever air pressure in the trailer supply line is at atmospheric pressure. We assume also, that the braking force developed by the protected source of air pressure and maintained by the mechanical device would comply with the requirements of S5.6.1 or S5.6.2 of the standard.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3912OpenMr. Jim Preisler, Senior Vice President, Drag Specialties, P.O. Box 9336, Minneapolis, MN 55440; Mr. Jim Preisler Senior Vice President Drag Specialties P.O. Box 9336 Minneapolis MN 55440; Dear Mr. Preisler: This responds to your letter of January 17, 1985, concerning Standar No. 205, *Glazing Materials*. Your company manufactures an aftermarket replacement motorcycle windscreen, which incorporates auxiliary wind deflectors. Standard No. 205 specifies that the upper portion of the windshield can be made out of item 1, 6, 10, or 11 glazing materials. The glazing used in the auxiliary wind deflectors can be made out of item 1, 2, 4, 10, or 11A glazing materials. You said that the glazing material used in the windscreen and deflector meets the requirements for both item 4 and 6 glazing materials. You asked whether you can mark both those components as item 4/6 glazing materials. The answer is that you can mark them as item 4/6 materials.; Section S6 of the standard sets out the certification and markin requirements for each item of glazing material. It provides that each piece of glazing material shall be marked, in accordance with section 6 of American National Standard Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways' Z-26.1 - 1977, January 26, 1977, as supplemented by Z26.1a, July 3, 1980, with a number signifying that it meets the performance requirement set for that particular glazing item number. In your case, the glazing material meets all of the requirements set for two separate item numbers. Since your product conforms to the requirements for both items 4 and 6 the agency has no objection to marking the components with both item numbers.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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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.