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: aiam1786OpenMr. J.C. Eckhold,Ford Motor Company,Dearborn, Michigan 48121; Mr. J.C. Eckhold Ford Motor Company Dearborn Michigan 48121; Dear Mr. Eckhold:#This responds to your letter of December 19, 1974, t Dr. Gregory, requesting confirmation of your interpretation of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*.#You described a brake booster system which combines vacuum and hydraulic boost, with the latter supplied by the power steering pump. In a Federal Register notice on June 28, 1974 (39 FR 24012, Docket No. 1-5, Notice 11) the NHTSA exempted certain hydraulic booster hoses from the requirements of Standard No. 106-74. Although no power steering fluid accumulator is used, the hydraulic booster hose which you described is exempt from the requirements of the standard because of the presence of redundant booster power supplied by the independent vacuum booster system.#A future amendment to Standard No. 106-74 to eliminate ambiguity respecting the standard's applicability to hydraulic booster hoses is currently under consideration.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
|
ID: aiam0894OpenMr. Tatsuo Kato, Engineering Representative, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Tatsuo Kato Engineering Representative Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Kato: This is in reply to your letter of August 14, 1972, on the subject o the test dummy specifications of Standard No. 208. I apologize for our delay in replying.; The alignment procedures of S8.1.11 of the standard cause the head t be aligned so that its vertical axis is almost in the same plane as the dummy's back. The necks on most commercial dummies are made of rubber and are installed at such an angle that, as you noted, the specified head alignment cannot be maintained. To correct this misalignment, the necks must be adjusted by shims or other means so that the correct alignment can be maintained.; The center of gravity of the upper thorax is approximated by dimension C and D in Table I and Figure 1 of SAE Recommended Practice J963. The precise location may vary slightly from one dummy model to another due to variances in the distribution of mass in the thoracic area.; Truly yours, Richard Dyson, Assistant Chief Counsel |
|
ID: aiam2000OpenMr. Russell O. Lightcap, Chief, Office of Equipment, Department of Transportation, P.O. Box 9067, Sacramento, CA 95816; Mr. Russell O. Lightcap Chief Office of Equipment Department of Transportation P.O. Box 9067 Sacramento CA 95816; Dear Mr. Lightcap: This responds to your letter of June 12, 1975, requesting confirmatio that you as a final-stage manufacturer would only have to check the application and release times of a truck whose chassis you shortened or lengthened in order to certify that vehicle to the requirements of Federal motor vehicle safety standard (FMVSS) No. 121, *Air Brake Systems*.; Certification of vehicles to the standard is an area which ou statutory scheme leaves to the manufacturers, and in which, aside from discussion of general principles, the agency has declined to issue statements of approval.; The National Highway Traffic Safety Administration has stated tha actual road tests by final stage manufacturers are not necessary to establish compliance with Standard No. 121 or other standards, where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. The agency has recognized that small organizations cannot be expected to test to the same scale or by the same methods as the large integrated automotive manufacturers. Supplier warranties and instructions are one of the primary means by which smaller assemblers are expected to use statutory 'due care' to see that their products conform.; From this discussion it should be apparent that verifying only th brake actuation and release functions will probably be an insufficient basis for certifying that the vehicle will comply, for example, with the stopping distance requirements of the standard. Engineering calculations may, however, satisfy you, in the exercise of due care, that the vehicle as modified meets all the requirements of the standard.; The incomplete vehicle documentation provided with the vehicle woul generally serve as the basis of certification to equipment requirements, to the degree that the equipment is undisturbed. The addition of an axle may cause the air reservoirs to no longer satisfy the air volume requirements of the standard.; Sincerely, Frank Berndt, Acting Chief Counsel |
|
ID: aiam2450OpenMr. K. W. Schang, Director - Vehicle Safety, Programs, American Motors Corporation, 14250 Plymouth Road, Detroit, MI 48232; Mr. K. W. Schang Director - Vehicle Safety Programs American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Schang:#This responds to American Motors Corporation's (AMC's September 9, 1976, request for confirmation that Standard No. 101, *Control Location, Identification, and Illumination*, permits the addition of a 'fan' symbol to a control that is identified by the word 'fan' in accordance with the requirements of S4.2.1.#The AMC interpretation is incorrect. Section S4.2.1 states in part:#>>>S4.2.1 . . . . A control may, in addition, be identified by a symbol, but only a symbol shown in column 3 or 4 shall be used. However, if the word 'None' appears in column 3, no symbol shall be provided. . . .<<<#Table I, whose columns are referred to in S4.2.1, contains an entry for 'Heating and Air Conditioning System,' and column 3 for that entry contains the word 'None'. This means that no symbol can be used in addition to the word 'fan' on the control for the fan control switch.#The language in the preambles to three proposals to amend Standard No. 101 that you list in your letter does not have the effect of amending the requirements of the standard itself. As you are no doubt aware, a recent proposal would amend Table I to include a symbol for the heating and air conditioning system, but this proposal has not yet been made final. A copy of the proposal is enclosed for your information.#Sincerely, Frank A. Berndt, Acting Chief Counsel; |
|
ID: aiam5395OpenMr. Donald P. Green 809 Huasna Road Arroyo Grande, CA 93420; Mr. Donald P. Green 809 Huasna Road Arroyo Grande CA 93420; Dear Mr. Green: This responds to your letter to this agency askin whether there is a State or Federal regulation prohibiting the use of passenger radial tires on recreational 'pull type' trailers. I regret the delay in responding. You explain that you were told by various tire dealers that radial tires should not be used on trailers because the soft sidewalls of radial tires could cause an uncontrollable swaying that could result in a serious accident. You then state that while towing a trailer mounted with four radial tires, you were caught in a crosswind which caused the trailer to jackknife, resulting in a serious accident. To begin, I am sorry to hear about your accident but am thankful that no one was hurt. The tire safety standards and regulations issued by the National Highway Traffic Safety Administration (NHTSA) require tires to be able to safely carry the load on a vehicle and to be labeled with important safety information, such as tire size, construction, and inflation pressure. There is nothing in our standards or regulations that prohibits the use of passenger car radial tires on trailers. In fact, Federal Motor Vehicle Safety Standard No. 120, 'Tire selection and rims for motor vehicles other than passenger cars,' expressly permits the use of passenger car tires on vehicles like trailers, provided that adjustment is made to the tire's load-carrying capacity. NHTSA also issues consumer advisories to alert consumers to certain practices that should be avoided, such as mixing radial and non-radial tires. However, we have never issued a consumer advisory on the use of passenger car radial tires on trailers, and we are not aware of any widespread hazard due to the use of such tires on trailers. Your State could have requirements for the use of tires on trailers. We suggest that you check with the California Highway Patrol for information on that issue. We regret we are unable to be more helpful. Should you have any further questions, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
|
ID: aiam0197OpenMr. Bernard Belier, U. S. Resident Engineer, U. S. Technical Research Corporation, 801 Second Avenue, New York, NY 10017; Mr. Bernard Belier U. S. Resident Engineer U. S. Technical Research Corporation 801 Second Avenue New York NY 10017; Dear Mr. Belier:#This is in reply to your letter, dated November 11 1969, in which you seek an interpretation as to how Federal Motor Vehicle Safety Standards (FMVSSs) 103 and 104 are applicable to cars equipped with right-hand drive or a central steering wheel.#For motor vehicles equipped with right-hand drive, the windshield areas to be defrosted and wiped by FMVSSs 103 and 104 respectively, are mirror images of those areas required for vehicles equipped with left-hand drive.#More information is required before a reply can be given on vehicles equipped with a central steering wheel. Defrosting and wiping areas requirements would naturally vary depending on the number and location of the front seat passenger seating positions in the vehicle equipped with a central steering wheel.#We trust that we have been of assistance to you.#Sincerely, Robert Brenner, Acting Director; |
|
ID: aiam1155OpenMr. J. W. Lane, Manager, Product Promotion, Technical, Publications and Packaging, Mobil Oil Corporation, 150 East 42nd Street, New York, New York 10017; Mr. J. W. Lane Manager Product Promotion Technical Publications and Packaging Mobil Oil Corporation 150 East 42nd Street New York New York 10017; Dear Mr. Lane: This is in reply to your letter of June 1, 1973 and confirms th telephone conversation with Mr. Vinson of my staff on June 14, 1973.; The amendments to Motor Vehicle Safety Standard No. 116 published o May 17, 1973 modified container labeling requirements only for silicone-based brake fluid and hydraulic system mineral oil (paragraph S5.2.2.3) and did not affect the requirements for conventional DOT 3 and DOT 4 fluids (paragraph S5.2.2.2) as your assumed. Therefore you appear to have no problem, and it is not necessary to consider your letter as a petition for reconsideration.; The sample label you enclosed appears to designate the contents a 'Super Heavy Duty Brake Fluid', rather than 'DOT 3 MOTOR VEHICLE BRAKE FLUID' as paragraph S5.2.2.2(e) requires. Otherwise, it is adequate compliance with paragraph S5.2.2.2.; Sincerely, Lawrence R. Schneider, Chief Counsel |
|
ID: aiam3168OpenMr. Thomas F. Brown, Mack Trucks, Engineering Division, P.O. Box 1761, Allentown, PA 18105; Mr. Thomas F. Brown Mack Trucks Engineering Division P.O. Box 1761 Allentown PA 18105; Dear Mr. Brown: This responds to your October 17, 1979, letter asking about the prope certification label for an intermediate manufacturer that alters the tires and rims on a chassis thereby affecting the gross axle and vehicle weight ratings. In your letter, you suggest an abbreviated certification label that would list the manufacturer's name and date of manufacture, and would make the statement that the vehicle will conform to certain standards if the incomplete vehicle document is followed. The agency agrees that this is a correct certification.; Intermediate manufacturers are required to attach labels to vehicle that they modify to indicate that some manufacturing operation has occurred on a vehicle between the manufacture of its chassis and its final manufacture. The intermediate manufacturer is permitted to select, from among a number of certification statements, the statement or statements that accurately represent the nature of the work undertaken by that manufacturer. Therefore, it is not necessary for an intermediate manufacturer to use all of the certification statements on its labels.; In the situation that you describe, the intermediate manufacturer wil make a statement on its label identical to one of the statements made by the chassis manufacturer. Although this appears to be redundant, it is necessary to have the intermediate manufacturer's label on the vehicle making the required certification statement so that a final-stage manufacturer can continue to rely upon the certification labels and upon the statements made in the incomplete vehicle document.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam4357OpenLyon L. Brinsmade, Esq., Porter & Clements, 3500 Republicbank Center, Houston, TX 77002; Lyon L. Brinsmade Esq. Porter & Clements 3500 Republicbank Center Houston TX 77002; Dear Mr. Brinsmade: This responds to your request for information regarding Federa regulation of semi-trailer manufacturing. You asked about Federal standards applicable to 'pneumatic aluminum tank type semi-trailers' which your client wishes to manufacture abroad and import into the United States. You were particularly concerned about specifications for aspects of the vehicle which pneumatically load and discharge substances into and out of the tank unit.; I would like to take this opportunity to provide some backgroun information concerning this agency's regulations. You are correct that the National Highway Traffic Safety Administration (NHTSA) administers Federal regulations for the manufacture and sale of new motor vehicles, including semi-trailers. NHTSA is authorized, under the National Traffic and Motor Vehicle Safety Act, to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. As you are aware, however, NHTSA does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Vehicle Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable requirements. (A general information sheet describing manufacturers' responsibilities under the Vehicle Safety Act is enclosed.); We note that the term 'manufacturer' is defined by section 102(5) o the Act to mean 'any person engaged in the manufacturing or assembling of motor vehicles or motor vehicle equipment, *including any person importing motor vehicles of motor vehicle equipment for resale*.' (Emphasis added.) Therefore your client, as a manufacturer of motor vehicles, is responsible for certifying compliance with all applicable motor vehicle safety standards. The procedure, specified in 49 CFR Part 567, requires also that the manufacturer provide safety information on the certification label, including the vehicle's gross vehicle weight rating and gross axle weight rating.; At this time, the only safety standards applicable to all trailers ar Safety Standard No. 108, *Lamps, reflective devices, and associated equipment*, Standard No. 120, *Tire selection and rims for motor vehicles other than passenger cars*, and Standard No. 115, *Vehicle Identification Number--Basic Requirements*. The content requirements for the identification number are found at Part 565. Your client's trailers also must meet Standard No. 106, *Brake hoses*, Standard No. 116, *Motor vehicle brake fluids*, and applicable requirements of Standard No. 121, *Air brake systems*. These standards are found in 49 CFR Part 571.; You were particularly concerned about Federal standards applicable t the pneumatic tank of the semi-trailer. There are no Federal motor vehicle safety standards for pneumatic tank units. However, even in the absence of an applicable safety standard, the Vehicle Safety Act imposes general responsibilities on manufacturers of motor vehicles and motor vehicle equipment regarding safety defects. Manufacturers of motor vehicles and motor vehicle equipment are responsible generally for ensuring that vehicles and equipment they manufacture are free from safety-related defects and can perform their intended function safely. If your client or the agency determines that a safety- related defect or noncompliance exists, your client is obligated under section 151 *et seq*. of the Act to notify purchasers of its product and remedy the problem without charge. Manufacturers who fail to provide notification of or remedy for a defect or noncompliance may be subject to a civil penalty of up to $1,000 per violation.; In addition to the regulations described above, your client should b aware of two procedural rules which apply to all manufacturers subject to the regulations of this agency. The first is 49 CFR Part 566, *Manufacturer Identification*. This rule requires your client to submit its name, address, and a brief description of the items of equipment it manufacturers to this agency within 30 days after it imports its products into the United States.; The other rule is 49 CFR Part 551, *Procedural Rules*. Subpart D o this regulation requires all manufacturers headquartered outside of the United States to designate a permanent resident of the United States as the manufacturer's agent for service of all process, notices, orders and decisions. This designation should be mailed to the Chief Counsel, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, DC 20590, and must include the following information:; 1. A certification that the designation is valid in form and binding o the manufacturer under the laws, corporate by-laws, or other requirements governing the making of the designation at the time and place where it is made,; 2. The full legal name, principal place of business and mailing addres of the manufacturer,; 3. Marks, trade names, or other designation of origin of any of th manufacturer's products which do not bear its name,; 4. A statement that the designation shall remain in effect unti withdrawn or replaced by the manufacturer.; 5. A declaration of acceptance duly signed by the agent appointed which may be an individual, a firm or a U.S. corporation, and; 6. The full legal name and address of the designated agent. In addition, the designation must be signed by one with authority t appoint the agent. The signer's name and title should be clearly indicated beneath his or her signature.; You asked whether your client's semi-trailers would be affected b regulations administered by other Federal agencies. If the semi-trailer will be used to transport a material designed by the Secretary of Transportation as a 'hazardous material' (see 49 CFR Part 172), then the transportation of that material is regulated by the Office of Hazardous Materials Transportation of the Research and Special Projects Administration (RSPA). You can contact the director of that office, Mr. Alan Roberts, at 366-0656 for more information on RSPA's regulations. In addition, you might be interested in information about regulations for interstate motor carriers issued by the Federal Highway Administration. Mr. Tom Kozlowski of the Office of Motor Carrier Standards, Federal Highway Administration, can provide you with more information. He may be reached at this address, Room 3403, or by telephone at (202) 366-1790.; I hope this information has been helpful. Sincerely, Erika Z. Jones, Chief Counsel |
|
ID: aiam3492OpenThe Blunt Company, 4500 City National Bank Building, Detroit, MI 48226; The Blunt Company 4500 City National Bank Building Detroit MI 48226; Gentlemen: This responds to Mr. Michael E. Murphy's letter of August 20, 1981, t Joan Griffin of my staff, regarding Safety Standard No. 127, *Speedometers and Odometers*. Mr. Murphy asks whether an electronic odometer that can be rendered useless by the simple unplugging operation would be legal under the odometer provision of the standard. When the odometer is unplugged, a 'blank' is registered in the odometer record. Mr. Murphy also asks whether the agency is considering any amendments or additions to the standard that are relevant to electronic odometers.; The National Highway Traffic Safety Administration (NHTSA) does no offer prior approval of compliance of any vehicle or equipment with any safety standard. It is the manufacturer's responsibility under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 *et seq*.) to determine whether its vehicle or equipment complies with all applicable safety standards and regulations and to certify its vehicle in accordance with that determination. Under certain circumstances, the agency is willing to give an informal opinion concerning whether a vehicle or item of motor vehicle equipment complies with a particular rule. Such opinions are not binding on NHTSA or on the manufacturer. However, in this case on the basis of the limited information contained in Mr. Murphy's letter, we cannot give even an informal opinion whether Chrysler's electronic odometer complies with Standard No. 127. We would need to see either the odometer itself or detailed pictures of it in order to make such a determination. We would also need to know if the odometer was manufactured in accordance with paragraphs S4.2.5.1, S4.2.5.2, S4.2.5.3, or S4.2.6, which specify four methods of resisting tampering.; I would emphasize that the odometer provisions of Standard No. 127 d not require that odometers be completely tamper proof. Rather, the rule simply requires that odometers resist tampering in one of four specified ways that are designed to leave visible evidence if reversal is attempted. It is possible for an odometer to comply with all the requirements of Standard No. 127 and still be susceptible to some form of tampering. Standard No. 127 was designed to prevent the mileage on odometers from being reduced. It was not designed necessarily to prevent tampering of the sort that would be possible with the Chrysler odometer where the odometer can be disconnected so that mileage is not recorded.; We stress that at this time no requirements for the manufacture an sale of odometers are in effect. The odometer provisions of Standard No. 127 (paragraphs S4.2-S5.2) are scheduled to take effect on September 1, 1982. Only odometers manufactured on or after that date must meet the requirements of the standard.; Further, on April 9, 1981, the NHTSA published a Notice of Intent (4 FR 21203) in which it announced that it would issue an NPRM to rescind Standard No. 127. The agency believes that such action may be warranted because there appear to be no direct safety benefits to be gained from the regulation and because of the potential for significant consumer savings. A notice proposing the rescission of the standard was published October 22, 1981 (46 FR 51788).; Finally, you should be aware that Title IV of the Motor Vehicle an Cost Savings Act (15 U.S.C 1981) states that no person shall disconnect an odometer with the intent to change the number of miles thereon. This provision may impact the use of the odometer to which you refer.; We hope you find this information helpful. Please contact this offic if you have further questions.; Sincerely, Frank Berndt, 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.