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: aiam1505OpenMr. Earl E. Eckert, 510 S. Avenue, Nevada, IA 50201; Mr. Earl E. Eckert 510 S. Avenue Nevada IA 50201; Dear Mr. Eckert: This is in reply to your letter of May 3, 1974, inquiring as to th applicability of the Federal odometer law to trucks over 16,000 pounds.; The Federal odometer regulation does not require transferors o vehicles with a Gross Vehicle Weight Rating of more than 16,000 pounds to provide an odometer disclosure statement upon transfer of the vehicle. By Gross Vehicle Weight Rating, the regulation is referring to the value specified by the manufacturer as the loaded weight of a single vehicle, which appears on its permanent certification label.; I have enclosed copies of pertinent portions of the Act and th regulation for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3538OpenMr. Eldridge G. Pentheny, Jr., Administration Engineer, Iveco Trucks of North America, Inc., 1730 Walton Road, P. O. Box 1102, Blue Bell, Pennsylvania 19422; Mr. Eldridge G. Pentheny Jr. Administration Engineer Iveco Trucks of North America Inc. 1730 Walton Road P. O. Box 1102 Blue Bell Pennsylvania 19422; Dear Mr. Pentheny: This responds to your letter asking whether your auxiliary heate toggle switch design meets the identification requirements of Standard No. 101-80, *Controls and Displays*.; By way of background information, I would point out that the agenc does not give advance approvals of vehicles or equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to determine whether its vehicle or equipment comply with applicable requirements. A manufacturer then certifies that its vehicles or equipment comply with all applicable standards. The following interpretation only represent the agency's opinion based on the information provided in your letter.; On the top of the switch is the fan symbol specified by Table 1 of th standard and an arrow pointed upward. When the top of the switch is depressed, the heater fan is activated to recirculate cab air without heating it. On the bottom of the switch is a flame symbol and an arrow pointing downward. When the bottom of the switch is depressed, the heater, including the heater fan, is activated. As explained below, use of the flame symbol for the heater does not meet the identification requirements of Standard No. 101-80.; Section S5.2.2 states: >>>Identification shall be provided for each function of ...*any heating and air conditioning system control, and for the extreme positions of any such control that regulates a function over a quantitative range. *If this identification is not specified in Tables 1 or 2, it shall be in word form unless color coding is used.* If color coding is used to identify the extreme positions of a temperature control, the hot extreme shall be identified by the color red and the cold extreme by the color blue. [Emphasis added.]; Since the auxiliary heater toggle switch is a heating system control each of its functions must be identified. The switch controls two functions, recirculating air by use of the fan and heating air.; Except for the identification of a heating and/or air conditioning fan neither Tables 1 or 2 specify identification for the functions of a heating system. Therefore, except for a heating and/or air conditioning fan, the functions of a heating system must be identified by words or color coding. I will separately discuss the identification required for the two functions of the auxiliary heater toggle switch.; Depressing the top of the switch activates the fan in order t recirculate air without heating it. This function may be characterized either as recirculation of air or as an on-off switch for the fan. Under the latter characterization, the fan symbol should be used since Table 1 specifies that symbol for a heating and/or air conditioning fan. Thus, the identification on the top of the toggle switch meets the requirements of Standard No. 101-80.; Depressing the bottom of the toggle switch activates both the fan an the heater in order to circulate and heat air. Since neither Table 1 nor Table 2 specify identification for the heating function, it must be in word form. (As explained below, color coding is not appropriate in this instance.) Use of the fan symbol in addition to words identifying the heating function is not necessary, even though the fan operates as part of the heating function, since there is no separate control for the fan. Since the bottom of the toggle switch does not identify the heating function by using words, it does not comply with the requirements of Standard No. 101-80.; In a telephone conversation with Edward Glancy of this office, yo indicated that you desire to use the flame symbol for purposes of international harmonization, noting that is the symbol specified by the ISO for heat. While Standard No. 101-80 specifies a number of other ISO symbols, it does not specify that symbol. Section S5.2.1(a) of the standard does permit the use of additional words or symbols for the purpose of clarity, so long as the words or symbols specified by the standard are used. Thus, you may use the ISO flame symbol if you also identify the bottom of the toggle switch by using words. Since you indicated that you are already producing the vehicles in question, we suggest that you consider simply adding a label with the words 'AUX. HEAT' (or other identifying words) adjacent to the bottom of the toggle switch.; In the above-mentioned telephone conversation, you asked whethe coloring the bottom of the toggle switch red would be considered color coding as that phrase is used in S5.2.2. The answer is no, since the use of any one color by itself does not constitute color coding. We interpret section S5.2.2 (quoted above) to require that color coding must be readily understandable. Although there may be other appropriate uses of color coding, the standard's example of using red and blue to identify the extreme positions of a temperature control is the only one that comes to mind. The use of red for the hot extreme is readily understood only when used in conjunction with blue for the cold extreme.; As you may know, it is the policy of this agency to both promot international harmonization and avoid unnecessary design restrictions. If you wish to produce vehicles using ISO symbols not specified by Standard No. 101-80, you may wish to consider filing a petition for rulemaking on that issue.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4707OpenMr. T. Chikada Manager, Automotive Lighting Engineering Control Dept. Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter with respect to tw types of decorative lighting devices intended for installation 'on the rear face, and at the top of optional motorcycle rear trunks respectively.' I regret the delay in responding. Type A and Type B would be installed on the same motorcycle. Type A would be installed at the top of the trunk. It consists of an elongated device, illuminated by LEDs when the taillamp is on. Type B is installed on the motorcycle itself. It is a rectangular device, illuminated by an incandescent bulb, which is mounted on the vertical centerline and is flanked by the tail and stop lamps. The distance between the center of the light sources on the two devices is 290mm. (approximately ll 1/2 inches). Both devices emit red light, and their maximum intensity is less than the minimum intensity of the taillamp. You have asked whether it is permitted to equip a motorcycle with the Type A and Type B accessory lamps. If the answer is affirmative, you have asked whether an LED could be used as the light source for Type B. You have also asked whether the maximum intensity of each device separately should be less than the minimum intensity of the tail lamp, or whether the combined maximum intensity of both devices should be less than the minimum intensity of the tail lamp. Paragraph S5.1.3 of Federal Motor Vehicle Safety Standard No. 108 (formerly S4.1.3) permits the installation of these lamps if they do not impair the effectiveness of the lighting equipment required by the standard. In this instance, the question to be asked is whether the devices, activated with the taillamps, impair the effectiveness of the taillamps, or the stop lamps. The devices are, in effect, supplemental taillamps, and as such, arguably do not appear to impair the effectiveness of the taillamps required by the standard no matter what their intensity is. The diagram of Type B indicates that the stop lamps and taillamps are in the same compartment, presumably incorporating a dual filament bulb. Although the stop lamps when activated are brighter than the taillamps, their proximity to the supplemental devices Type A and Type B, each of which are emitting a red light, leads to the possibility that the stop signal would not be as effective as it would be were there no other red lights in the vicinity, and hence impaired within the meaning of S5.1.3. A stop signal must be instantly perceived so that a following driver may determine appropriate action to take. However, we note that this configuration is similar to other stop/taillamp configurations on many vehicles in use on the highways. This would indicate that such configurations do not result in impairment. Thus, the answer to your first question is that both Types of devices are permitted under the standard. Your second question is whether LEDs are acceptable light sources for Type B. Since there is no restriction on light sources for a lighting device not required by Standard No. 108, you may use the LEDs as light sources. Your third question is whether the maximum intensity of Type A and Type B, separately, should be less than the minimum intensity of the taillamp. Even though Type A and Type B are optional devices, in the configuration depicted where Type B is immediately flanked on both sides by a taillamp, the appearance of the three lamps would be that of a multicompartment lamp, even though they may actually be separate. To help assure that impairment of either the taillamp or stop lamp does not occur, the intensity of Type B should be identical with that of the taillamps. Otherwise, observers may assume that Type B (which you intend to have an intensity less than a taillamp) is actually the taillamp, and the actual taillamps (which you intend to have an intensity greater than Type B) might appear to be stop lamps that are continually on. This would be deemed impairment since there would be three intensity levels, increasing the possibility of confusion of the intent of the lamps. As for Type A, its vertical separation decreases the possibility for confusion. If the light sources are LEDs, the color would be a different shade of red that the stop and taillamps. Thus, the intensity is less important. However, it functions as an auxiliary taillamp and should be within the same intensity range as the original equipment taillamps. Finally, you asked whether the combined maximum intensity of both devices would be less than the minimum intensity of the taillamps. Again, this would create three levels of intensity, and could cause confusion in understanding the intent of the lamps. As noted above, the individual intensities should be similar to the intensity of the taillamps. I hope that this answers your questions. Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam1856OpenHonorable Henry B. Gonzalez, House of Representatives, Washington, DC 20515; Honorable Henry B. Gonzalez House of Representatives Washington DC 20515; Dear Mr. Gonzalez: This responds to your March 7, 1975, request for a copy of Standard No 121, *Air brake systems*, a discussion of the Federal excise tax on trucks and trailers, and an explanation of the manufacturer's certification responsibilities in the case of this standard. I have enclosed a copy of the standard, along with several amendments of it which have been recently issued.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391 e seq.) provides that the Secretary of Transportation establish performance standards for motor vehicle safety (S 103) and that the manufacturer be responsible for designing solutions that meet those performance requirements and certifying compliance with them (S 114). This law is intended to permit manufacturers latitude in choosing the designs best suited to their needs.; In the case of Standard No. 121, the manufacturer who completes vehicle will receive documentation from the chassis manufacturer that sets out the limits under which he can certify the vehicle without conducting tests or further engineering calculations. If he makes more modifications than authorized by the documentation, he must develop some basis of certification that the vehicle, as modified by him, would still be capable of meeting the requirements if tested by the Department's National Highway Traffic Safety Administration. Warranties from component suppliers, or the manufacturer's own engineering calculations could form the basis of certification.; The Federal excise tax to which you refer is a 10 percent tax on ne trucks, buses, and trailers which have a gross vehicle weight rating of more than 10,000 pounds. I have enclosed a discussion of the tax as it relates to the other taxes that accrue to the Highway Trust Fund.; Sincerely, James B. Gregory, Administrator |
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ID: aiam2779OpenR. L. Ratz, P.E., Product Safety Engineering, Grumman Flxible Corporation, 970 Pittsburgh Drive, Delaware, OH 43015; R. L. Ratz P.E. Product Safety Engineering Grumman Flxible Corporation 970 Pittsburgh Drive Delaware OH 43015; Dear Mr. Ratz: This responds to your recent letter asking whether Safety Standard No 209, *Seat Belt Assemblies*, and Safety Standard No. 210, *Seat Belt Anchorages*, would be applicable to a Type I seat belt assembly used as a securement device for wheelchairs in an urban transit bus.; Safety Standard No. 209 is an equipment standard that is applicable t any seat belt manufactured for use on passenger cars, multipurpose passenger vehicles, trucks or buses. Therefore, the seat belt in question would have to comply with the performance requirements of that standard.; Safety Standard No. 210, however, only specifies requirements for sea belt anchorages at the driver's position on buses. Since the assembly you are concerned with would be at a passenger seating position in the bus, it would not have to comply with the anchorage requirements of Standard No. 210.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0744OpenMr. Frank R. Raidl, Vice President, All Brake & Drive Unit Service, Inc., 5551 Ogden Avenue, Cicero, IL 60650; Mr. Frank R. Raidl Vice President All Brake & Drive Unit Service Inc. 5551 Ogden Avenue Cicero IL 60650; Dear Mr. Raidl: This is in response to your letters of February 14 and April 20, 1972 I apologize for our delay in answering your inquiries. You state that your G.M.C. truck dealership installs fifth wheels, saddle gas tanks, mirrors, marker lamps and tractor protection brake equipment and you inquire what your obligations are with respect to the Manufacturer Identification and Certification regulations (Parts 566 and 577 (sic) respectively).; Installation of fifth wheels would make you a 'final-stag manufacturer', as defined in Part 568, Vehicles Manufactured in Two or More Stages, because you perform 'such manufacturing operations on an incomplete vehicle that it becomes a completed vehicle', other than the addition of 'readily attachable components, such as mirror or tire and rim assemblies.' Installation of the other items you listed would generally not make you a final-stage manufacturer, since installation of these items does not fulfill the above criteria.; As a final-stage manufacturer, you are required under Part 566 Manufacturer Identification, to submit the information specified in S566.5. Your submittal of January 18, 1972, satisfies this requirement.; As a final-stage manufacturer, you are also required under part 567 Certification, to affix a certification label on the vehicle you manufacture. In addition, Part 573 requires the submission of quarterly reports regarding vehicle production and defect notifications (49 CFR S 573.5) and of copies of all other notices, bulletins and communications sent to more than one dealer or purchaser regarding any defect in such vehicles, whether or not safety-related.; I am enclosing copies of Parts 566, 567, 568, and 573 for you information. These should also answer your questions as to the format of the required submittals.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2283OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P. O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P. O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to Blue Bird Body Company's March 29 and 31, 1976, an April 14, 1976, requests for confirmation of several interpretations you have made regarding the new safety standards for school buses and the definition of 'school bus' as they become effective in October 1976.; Your interpretation is correct that 'bus passenger compartment' as use in S5.2.3.1 of Standard No. 217, *Bus Window Retention and Release*, means that portion of the bus that is rearward of the forwardmost point on the windshield.; You request confirmation that the requirement in S5.7(a) of Standar No. 220, *School Bus Rollover Protection*, to open emergency exits during the application of force to the bus roof are inappropriate and therefore not applicable in the case of roof exits. Your interpretation is correct, and the NHTSA intends to modify the language of Standard No. 220 appropriately.; You request confirmation that the knee impact requirement of S5.3.2. of Standard No. 222, *School Bus Passenger Seating and Crash Protection*, does not apply to the rear row of seating in a school bus because there is no passenger seating behind this row. Your interpretation is correct. I would like to point out that the seat back of the rear row of seating also is not subject to the requirements of S5.3.1.1 for the same reason. Your are also correct that 'school bus passenger seat' as defined in S4 does not include a wheelchair that is placed in a school bus to transport non- ambulatory bus passengers. Our response on other issues concerning special arrangements for handicapped passengers will be forthcoming as a response to the outstanding Sheller-Globe petition for reconsideration of Standard No. 222.; In your March 31, 1976, letter you asked whether a bus that is sold fo purposes that include carrying kindergarten and nursery school children to and from school or related events would be considered a school bus under the redefinition of 'school bus' that becomes effective October 27, 1976 (40 FR 60033, December 31, 1975). The answer to your question is yes, because the statutory definition underlying the NHTSA definition of school bus specifically lists preprimary students as passengers of school buses. See 15 U.S.C. S 1391(14).; In your April 14, 1976, letter you ask whether the requirement o S5.3.1.3 of Standard No. 222 for a minimum 'contact area' on a described spherical head form refers to the area of actual contact on the surface of the spherical head form, or the area of contact on the head form as seen in projected view. The 'contact area' refers to the area of actual contact on the surface of the head form.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5546OpenMr. Dietmar K. Haenchen Manager, Vehicle Regulations Volkswagen of America, Inc. 3800 Hamlin Road Auburn Hills, MI 48326; Mr. Dietmar K. Haenchen Manager Vehicle Regulations Volkswagen of America Inc. 3800 Hamlin Road Auburn Hills MI 48326; "Dear Mr. Haenchen: This responds to your request for an interpretatio of Standard No. 118, Power- operated window, partition, and roof panel systems. You asked whether the 'squeezing force limitation' of S5 applies only to the first attempt to close a power operated window, partition, or roof panel system (power-operated system) and not to immediately following attempts to close. You explained that an operator may initiate more than one closing attempt in order to assure the closing of the power operated system under adverse conditions such as low temperature or the presence of ice in the power operated system's track. As discussed below, the S5 squeezing force limitation applies to each closing attempt. By way of background information, Standard No. 118 requires that a power operated system, while closing, must comply with one of two alternative provisions. The first, S4, generally specifies requirements for situations where a person is expected to be in the immediate vicinity of the vehicle to supervise the closing. The second, S5, covers 'unsupervised' closings, i.e., automatic closings or closings where the person initiating the closing is further away from the vehicle. In the rulemaking establishing S5, NHTSA recognized that unsupervised closings increase the risk that persons, especially children, could be caught between a closing system and the frame. Therefore, to the extent that a power operated system permits unsupervised closings, the agency decided to require an automatic reversal mechanism that reverses the window direction upon its meeting an obstruction. More specifically, if an obstruction is between 4 and 200 mm from any part of the vehicle structure with which the closing system mates, S5 requires window reversal before a force of 100 Newtons is encountered. S5 does not specify different squeezing force limitation requirements for different closing attempts. Therefore, a power operated system must meet the same requirements for each closing attempt. We note that since the requirements of S5 address unsupervised closings, the same safety concerns about children being caught between a closing system and frame would be relevant to each closing attempt. I note that NHTSA decided not to apply the S5 squeezing force limitation requirement to unsupervised closings within the area between 4 mm and any part of the vehicle structure with which the closing system mates. The agency recognized that injury from system closure is not possible in this area, and that unnecessary automatic reversal could result from the system's misalignment or obstruction from ice. Thus, during unsupervised closing, if the system encounters an obstruction less than 4 mm from any part of the vehicle structure with which the closing system mates, the power operated system need not reverse. I hope that this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam2329OpenMr. David E. Martin, Director, Automotive Safety Engineering, General Motors Corporation, General Motors Technical Center, Warren, Michigan 48090; Mr. David E. Martin Director Automotive Safety Engineering General Motors Corporation General Motors Technical Center Warren Michigan 48090; Dear Mr. Martin: This responds to General Motors Corporation's May 27, 1976, petition t commence rulemaking to amend Standard No. 105-75, *Hydraulic Brake Systems*, in order to return one sentence to the text of S5.1.5.2(a) that was omitted in a September 17, 1975, revision of that section (40 FR 42872). The sentence reads:'However, the maximum control force for the fifth stop in the case of a vehicle manufactured before September 1, 1976, shall be not more than plus 60 pounds of the average control force for the baseline check (but in no case more than 110 pounds).'; The National Highway Traffic Safety Administration considers a petitio to amend the standard to be unnecessary because the omission was inadvertent and did not constitute a substantive change to the requirements of the standard. Therefore, an interpretative amendment to conform the language to that intended will be forthcoming in the near future. Interested persons are notified that the interim control force value has been in effect for all vehicles of 10, 000 pounds gross vehicle weight rating or less despite the omission of the sentence on September 17, 1975.; Thank you for bringing this omission to the attention of the agency. Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam0314OpenMr. P.H.G. Morgan, Managing Director, Morgan Motor Company, Ltd., Pickersleigh Road, Malvern Link, Worchestershire, England; Mr. P.H.G. Morgan Managing Director Morgan Motor Company Ltd. Pickersleigh Road Malvern Link Worchestershire England; Dear Mr. Morgan: This is in reply to your letter of March 17, 1971, in which yo requested further clarification of the test procedures of the standard on side door strength, Standard No. 214. Your diagram of the Morgan Plus 8 shows a horizontal line drawn across the door 5 inches above the lowest point of the door. This would appear to be an accurate depiction of the location of the lower edge of the loading device as specified in the standard. You express concern that the line is a considerable distance from the ground, but under the requirements of the standard, the height above the lower edge of the door is the relevant height, and not the height above ground.; I hope this will help to resolve your questions with respect t Standard No. 214.; Sincerely, Lawrence R. Schneider, Acting 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.