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: 16452.wkmOpenMr. Barry Livett Dear Mr. Livett: Please excuse the delay in responding to your letter to Mr. Arthur H. Neill, Jr. formerly of this Department, requesting a list of Chinese tire companies that have been granted certification by the U.S. Department of Transportation. Please be advised that Mr. Neill has retired. You state that you work for the merchant banking arm of the Bank of China and are preparing information on the Chinese tire industry. In connection with this, you request from us a list of Chinese tire companies and/or names of Chinese tire brands that have been granted any form of U.S. certification. The law of this country establishes a self-certification system in which manufacturers of motor vehicles and motor vehicle equipment, which includes tires, themselves certify that their products meet all applicable Federal motor vehicle safety standards. Thus, this agency does not certify, approve, disapprove, endorse, or assure compliance of any motor vehicle or item of motor vehicle equipment prior to its being introduced for sale in the retail market. Rather, this agency enforces compliance with the standards after the fact; that is, we purchase vehicles and equipment that are available to consumers in the retail market and test them for compliance. If they are found to comply, nothing further is done. If they are found not to comply, the manufacturer is responsible for correcting the problem(s), by repair or otherwise, at no expense to the customers. We do, however, issue identification codes to each plant of each manufacturer that produces tires for sale in the United States. The purpose of such codes is that in the event of a tire recall, the codes will enable this agency to readily identify the plant in which the affected tires were produced. Therefore, enclosed in accordance with your request is a list of tire companies in China to which we have issued tire codes as of January 22, 1998. I hope this information is helpful to you. Should you have any further questions or need additional information, please feel free to contact Walter Myers of my staff at this address or at 011-202-366-2992, or by fax at 011-202-366-3820. Sincerely, |
1998 |
ID: 16507.drnOpenCarlton R. Csiki, Division Chief Dear Mr. Csiki: This responds to your November 10, 1997, request that we clarify our pupil transportation policies concerning which vehicles we believe should be used to carry students to school-related events. I appreciate this opportunity to address your concerns. Your letter follows up on an October 15, 1997, letter that Administrator Ricardo Martinez, M.D. sent to pupil transportation officials of each state which recommended, among other things, that certified school buses should be used to transport children to and from school and school-related events. You state that Connecticut does not prohibit the use of buses other than school buses (hereinafter referred to as "non-school buses") to transport students to and from school-related events. You believe that it may not be feasible to transport students on long field trips in a school bus, and ask whether the recommendation is contrary to provisions in Highway Safety Program Guideline No. 17, Pupil Transportation Safety (Guideline 17), which appear to make allowance for the use of "school-chartered buses" (which are non-school buses) for special events. Our position is that children are safest when in school buses and thus these vehicle should be used rather than conventional buses, certainly when transporting children on a regular basis to and from school-related events. It should be noted that Federal law prohibits persons from selling new non-school buses if the vehicles will be used significantly for school-related events. However, non-school buses may be occasionally rented for special school-related events, because an occasional rental does not constitute "significant use" as a school bus. Guideline 17 reflects the real world possibility that a non-school bus might have to be rented from time to time for a special event. Under the guideline, these buses, which the guideline refers to as "school-chartered buses," would be subject to the guideline's recommendations for the safe operation of school vehicles but not to the recommendations for equipping school buses with mirrors, lamps and stop arms and identifying them with signs and yellow paint. This distinction was to promote safety on trips to special events without imposing unreasonable burdens on school administrators. The guideline's provisions for non-school buses only address the occasional, short-term rental of the vehicles. As for buses that are regularly used for school-related events, there is no question that school buses are among the safest vehicles on the road today and should be used instead of non-school buses to transport school children. We ask you and your colleagues to further consider choosing school buses over non-school buses for transporting students to these school-related events. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, |
1998 |
ID: 1651yOpen Mr. Wendell D. Kegg Dear Mr. Kegg: This responds to your letter seeking an interpretation of Federal Motor Vehicle Safety Standard No. 110, Tire Selection and Rims. You were uncertain about section S4.3.1's requirements related to the inflation pressure for spare tires specified on vehicle placards. You asked whether a vehicle manufacturer can specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on the tire's sidewall. As you know, FMVSS 110 sets forth requirements related to vehicle placards in passenger cars. Section S4.3 requires that the placard be "permanently affixed to the glove compartment door or an equally accessible location" and display the vehicle capacity weight; the designated seating capacity; the vehicle manufacturer's recommended cold tire inflation pressure for maximum loaded weight and, subject to the limitations of S4.3.1, for any other manufacturer-specified vehicle loading condition; and the vehicle manufacturer's recommended tire size designation. FMVSS 110 does not have any provision requiring the inclusion of information on the placard related to spare tires or air pressure related to spare tires. Accordingly, a passenger car manufacturer may, but is not required to, specify information related to spare tires on the placard. In response to your question whether a passenger car manufacturer can specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on the spare tire's sidewall, section S4.3.1 of FMVSS 110 states that the vehicle placard must not specify an "inflation pressure other than the maximum permissible inflation pressure" required to be molded on the tire itself by section S4.3 of FMVSS 109, New Pneumatic Tires, unless the alternative inflation pressure satisfies the three conditions set forth in S4.3.1. The first condition requires that the alternative inflation pressure be less than the maximum permissible inflation pressure. The second condition requires that the vehicle loading condition be specified for the alternative reduced pressure. The third condition requires that the tire load rating be specified by an individual manufacturer for the tire size at that inflation pressure that is not less than the vehicle load on the tire for that vehicle loading condition. Accordingly, a vehicle manufacturer could not specify on its placard an inflation pressure that exceeds the maximum permissible inflation pressure. I am enclosing a December 13, 1984 letter to Mr. Alberto Negro of Fiat, which explains the agency's position concerning a manufacturer's specification on the placard of an inflation pressure that exceeds the maximum inflation pressure molded on the tire. As that letter indicates, a manufacturer would have to meet each of the conditions specified in section S4.3.1, including that the alternative inflation pressure must be less than the maximum permissible inflation pressure. Because spare tires are subject to these requirements like any other pneumatic tire, a vehicle manufacturer could not specify a higher inflation pressure for a spare tire than the maximum inflation pressure molded on that tire. If you have any further questions or need additional information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely,
Erika Z. Jones Chief Counsel Enclosure /ref:109#110 d:l/l8/89 |
1970 |
ID: 16528.drnOpenThe Honorable Phil English Dear Congressman English: Thank you for your letter on behalf of your constituent, Mr. Gary New of New Car Rental in Erie, who asks about this agency's school bus regulations. Your letter has been referred to my office for reply. Mr. New wishes to know whether he can rent 15-passenger vans to schools to transport students to sports events. As explained below, Federal law permits the lease of a van on a one-time or very occasional basis. However, because States have the authority to regulate the use of vehicles, Mr. New should contact Pennsylvania officials to see if State law would permit the lease of the vans. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue and enforce Federal motor vehicle safety standards applicable to new motor vehicles. Our statute at 49 U.S.C. 30112 requires any person selling or leasing a new vehicle to sell or lease a vehicle that meets all applicable standards. Accordingly, persons selling or leasing a new "school bus" must sell or lease a vehicle that meets the safety standards applicable to school buses. Our statute defines a "school bus" as any vehicle that is designed for carrying 11 or more persons and which is likely to be "used significantly" to transport "preprimary, primary, and secondary" students to or from school or related events. 49 U.S.C. 30125. Therefore, a 15-passenger van that is likely to be used significantly to transport students is a "school bus." If the new van is sold or leased to transport pupils (e.g., leased on a regular or long-term basis to a school), the vehicle must meet NHTSA's school bus standards. Conventional 15-passenger vans cannot be certified as doing so, and thus cannot be sold or leased, as new vehicles, to carry students on a regular basis. However, a one-time or very occasional rental would be permitted. Because such use would not constitute "significant use" as a school vehicle, the van would not be a "school bus" and thus may be leased to the school for the special event. The requirement to sell or lease complying school buses applies only to new vehicles. If a school wishes to buy a used 15-passenger van or enter into a long-term lease, NHTSA would not require the seller or lessor to sell or lease a school bus. However, NHTSA believes that school buses are one of the safest forms of transportation in this country, and therefore strongly recommends that all buses that are used to transport school children be certified as meeting NHTSA's school bus safety standards. Further, using 15-passenger vans that do not meet the school bus standards to transport students could result in increased liability in the event of a crash. Since such liability would be determined by State law, Mr. New may wish to consult with his attorney and insurance carrier for advice on this issue. I hope this information will assist you in responding to your constituent's concerns. I have enclosed a question-and-answer sheet on "Dealer's Questions about Federal School Bus Safety Requirements." If you have any further questions, please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992. Sincerely, |
1997 |
ID: 1652yOpen Mr. Leonard M. Perkins Dear Mr. Perkins: Secretary Burnley has asked me to respond to your letter of September 7, 1988, with respect to your lighting device. In essence, this is a center high-mounted stop lamp, with turn signal lamps adjacent to it. You believe that high-mounted turn signals "joined with the rear window brake light should have a dramatic effect on rear and side collisions", but you have been told that "this conception is at present illegal." Paragraph S4.4 of Federal Motor Vehicle Safety Standard No. l08 states that "no high-mounted stop lamp shall be combined with any other lamp or reflective device." We interpret this as prohibiting lamps or reflective devices that share a single lens or compartment with the center highmounted lamp. Your device shows lamps adjacent to the center highmounted lamp but not combined with it. Therefore, your device is not prohibited by that paragraph of the standard if you wish to market this device as original equipment. The next question to ask is whether it impairs the effectiveness of required lighting equipment (paragraph S4.1.3), principally the center stoplamp. For example, if the yellow turn signals were too bright or if the color of the turn signal were red, these lamps might "impair the effectiveness" of the center stoplamp. However, this is a determination to be made, in the first instance, by the manufacturer of the vehicle who must certify compliance with Standard No. l08. If you wish to sell your device in the aftermarket, it is acceptable under Federal law if its installation does not adversely affect the operation of motor vehicle equipment installed in accordance with a Federal motor vehicle safety standard so that the equipment would no longer comply with the standard. Assuming that the installation does not have this effect, the legality of installing or using such a device must then be determined according to the laws of any State in which a vehicle so equipped is registered or operated, and these auxiliary lamps must comply with any State requirements. We cannot advise you on State laws. One source of advice is the American Association of Motor Vehicle Administrators, 4600 Wilson Blvd., Arlington, Va. 22203. Sincerely,
Erika Z. Jones Chief Counsel ref:108 d:l/l8/89 |
1970 |
ID: 16537.drnOpenMr. Karl-Heinz Ziwica Ref: A:FW22197 Dear Mr. Ziwica: This responds to your request for an interpretation of Standard No. 102, Transmission shift lever sequence, starter interlock, and transmission braking effect as it applied to a proposed BMW transmission design with electronic shifting controls. We have reviewed the arguments presented in your request for an interpretation, and cannot agree with BMW that S3.1.1 Location of transmission shift lever positions on passenger cars, S3.1.3 Starter interlock and S3.1.4 Identification of shift lever positions "are not applicable to automatic transmissions without a shift lever." However, the agency is carefully reviewing BMW's related petition for rulemaking submitted on November 19, 1997, the same date as the request for interpretation. The agency will inform you of its decision on the petition for rulemaking after it has completed its review of your petition. I hope this information is helpful. If you have any questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, |
1998 |
ID: 16539.wkmOpenMr. Donald W. Vierimaa Dear Mr. Vierimaa: Please pardon the delay in responding to your letter to Dr. Ricardo Martinez, the National Highway Traffic Safety Administration (NHTSA) Administrator, in which you referred to subsection S5.3, Federal Motor Vehicle Safety Standard (Standard) No. 120, Tire selection and rims for motor vehicles other than passenger cars (49 CFR 571.120), and asked whether kilograms and pounds can be abbreviated kg and lb respectively. The answer is yes. Subsection S5.3, Label information, requires that each vehicle other than passenger cars shall show tire and rim labeling as specified in S5.3.1 and S5.3.2 respectively, "in the format set forth following this section." Examples of the required labeling are set forth following paragraph S5.3.2, entitled "TRUCK EXAMPLE -- SUITABLE TIRE-RIM CHOICE." In those examples the words "kilograms" and "pounds" are spelled out, with no indication that abbreviations may be used. The labeling is required to be shown "in the format" set forth in the examples. In a denial of a petition for reconsideration and denial of a petition for rulemaking concerning our child seat standard published in the Federal Register on June 4, 1993 (58 FR 31658) (extract enclosed), NHTSA stated:
Since no reference is made to the use of abbreviations, it is our opinion that the requirement that the specified labeling be "in the format" shown at the end of the section does not prohibit the use of appropriate abbreviations. For the sake of brevity, NHTSA has always routinely used abbreviations throughout its standards, especially on prescribed labels. This saves scarce space on such labels and the more commonly used abbreviations, such as "kg" for kilograms and "lb" for pounds, are widely known and recognized by the public. Accordingly, those abbreviations are tantamount to the full spelling of those words and may be used interchangeably with the full spelling of those words in the labeling required by S5.3, Standard No. 120. I hope this information is helpful to you. Should you have any questions or need additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992, fax (202) 366-3820. Sincerely, |
1998 |
ID: 1653yOpen The Honorable Jim Bates Dear Mr. Bates: This is in reply to your letter of October 19, l988, with reference to an invention by your constituent, Angelo R. Collica. You have asked for "the requirements necessary to install lighting devices on motor vehicles." Since we do not have a description of Mr. Collica's device, our answer must therefore be general in nature. There are different answers, depending upon whether a device is installed before or after the first sale of a vehicle. A supplementary lighting device installed on a vehicle by a vehicle manufacturer or dealer before its first sale to a consumer is permissible as long as it does not impair the effectiveness of lamps, reflective devices, and associated equipment that are required by the Federal motor vehicle safety standard on lighting. Examples of impairment are diminished brightness of a lamp due to interference with its wiring, or a confusion of its function through close proximity or signal of the supplementary device. In general, also, all lighting equipment other than hazard warning/turn signals, and headlamps flashed for signalling purposes, must be steady-burning in use. Whether a device creates an impairment is a determination to be made by the vehicle manufacturer in its certification of compliance with the Federal safety standards, or by the dealer, before sale of the vehicle. The installation of a supplementary lighting device on a vehicle after the vehicle's first sale to a consumer is acceptable under Federal law, provided that the installation does not degrade the performance of any device or element of design installed in accordance with any Federal motor vehicle safety standard. This prohibition applies to vehicle manufacturers, distributors, dealers and repair businesses. It does not, however, apply if the supplementary lighting device is installed by the vehicle owner. The legality of operating a supplementary device, installed after vehicle sale, is primarily determinable under the laws of any State in which a vehicle using it is registered or driven. The American Association of Motor Vehicle Administrators, 4600 Wilson Blvd., Arlington, Va. 22203, is able to advise on State laws. I hope that this has been helpful to you. Sincerely,
Diane K. Steed /ref:108 d:l/23/89 |
1970 |
ID: 16613.ztvOpenMr. Yanichi Yoshimoto Dear Mr. Yoshimoto: This is in reply to your letter of November 28, 1997, to the Associate Administrator for Safety Performance Standards, asking for an interpretation of the humidity test requirements of Federal Motor Vehicle Safety Standard No. 108. For your future reference, requests for interpretation should be addressed to the Chief Counsel. After a humidity test, paragraph S7.4(h)(6) of Standard No. 108 requires the inside of a headlamp to "show no evidence of delamination or moisture, fogging or condensation visible without magnification." You ask whether moisture is nevertheless permissible if it is located in an area of the interior where it cannot affect the photometric performance of the headlamp. The requirement is absolute: no moisture that is visible without magnification is permitted on the interior of a headlamp after the humidity test, whether or not it is located in an area related to the photometric performance of the headlamp. Thus, moisture is not permissible in the situation shown in your Case 1 (moisture on the lens area of the turn signal lamp portion of a single compartment lamp) or your Case 2 (moisture in a location outside the photometric effective area of the headlamp). Sincerely, |
1998 |
ID: 16614-1.pjaOpenMr. Shane K. Lack Dear Mr. Lack: This responds to your request that we review your draft summaries and interpretations of Federal Motor Vehicle Safety Standards 205 (49 CFR 571.205, Glazing materials) and 217 (49 CFR 571.217, Bus emergency exits and window retention and release). We apologize for the delay in responding. Because your documents are lengthy (36 pages) and contain so many statements, questions, and interpretations, we are unable to address each individual point in this letter. Instead, we will confirm that, in general, your summaries and interpretations of our standards are correct. We offer the following answers to your questions and corrections to a few of your interpretations, with reference to the page number and line number of your summary. For brevity, we have paraphrased the relevant portions of your letter in italics. Federal Motor Vehicle Safety Standard No. 205, Glazing materials
The answer to the first part of your question is yes. The material of which the glazing is constructed is not specified. Both Standard 205 and the American National Standard, Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways -- ANSI Z26.1-1977 (hereafter referred to as ANSI Z26.1, which is incorporated by reference in the CFR) may refer to specific kinds of glazing in headings. Examples of this are in paragraph S5.1.2.3 of the standard, which refers to "flexible plastics," and the column headings of Table 1 in ANSI Z26.1, which lists materials such as "laminated glass." These headings are for illustrative purposes only, to indicate the material and construction that typically is used to meet the enumerated tests. See note 1 to Table 1 in ANSI Z26.1, which specifically states that future materials that meet the enumerated tests may be used. Therefore, any material that meets all the tests for a particular item of glazing complies with the standard, regardless of composition or construction.
Again, the mention of safety plastics is illustrative. The words "safety plastics" should not have been included in the standard. However, the performance-based method (i.e., whatever meets the tests) of determining compliance is maintained even for item 12 glazing.
The answer to both questions is yes.
The list of approved glazing types on page 2 is correct.
Yes.
Yes.
No, it does not. Federal Motor Vehicle Safety Standard No. 217, Bus emergency exits and window retention and release
We assume when you say "to be counted" you mean whether a particular exit would count for determining if the bus has the correct number of exits specified in Standard No. 217. When conducting a compliance inspection of a new vehicle, the National Highway Traffic Safety Administration (NHTSA) would normally have the manufacturer's certification data showing which exits are designated as emergency exits. If an exit did not comply in some way, this agency would not "uncount" that exit for meeting exit number and exit area requirements. Instead, the vehicle would be considered to have failed only the requirements that were not fulfilled. For example, if an otherwise compliant exit were not labeled, the bus would fail only the S5.1.1 labeling requirement. The area for that exit would still be counted for meeting the emergency exit number and area requirements.
The first sentence of your interpretation is correct. Your computation in the second sentence is incorrect. The minimum emergency exit opening computes to 1296 sq. cm for a 33cm X 50cm ellipsoid. The area of an ellipse = 3.14 times the product of the major and minor semi-axes.
While it is true that there is no prohibition explicitly stated in the standard, NHTSA interprets its regulations consistently with their purposes. The purpose behind the emergency exit requirements, which is clearly reflected paragraph S2 and in its preambles on the subject, is to provide readily accessible emergency egress. It is highly unlikely that a manufacturer would actually place emergency exits in such an unusual configuration. If it did, NHTSA would not regard the emergency exit placed on top of another as being accessible, and would not count it toward meeting the requirements.
Paragraph S5.2.1 allows manufacturers of non-school buses to meet the specifications for non-school buses in S5.2.2 or the specifications for school buses in S5.2.3. If S5.2.2 is followed and a roof exit is needed because a rear exit cannot be provided, then paragraph S5.2.2.2 specifies that the roof exit is to be located in the rear half of the bus. If S5.2.3 is followed, then S5.3.2.2(b) specifies both the longitudinal and lateral position of all roof exits.
We do not know to which interpretation you are referring. A computerized search of all our previous interpretation letters did not reveal an interpretation with those words. It is true, however, that the provisions specifying that the release mechanisms can only be actuated by applications of a certain magnitude of force in certain directions are designed to prevent inadvertent opening of an exit. I hope this is helpful. Again, my sincere apologies for the delay in our reply. If you have any further questions, please feel free to contact us at (202) 366-2992. Sincerely, |
1999 |
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.