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: aiam2703OpenMr. J. Kevin Smith, Director, Product Reliability and Quality, North American Operations, International Harvester, 401 North Michigan Avenue, Chicago, IL 60611; Mr. J. Kevin Smith Director Product Reliability and Quality North American Operations International Harvester 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Smith: This responds to your October 3, 1977, letter questioning the positio of the National Highway Traffic Safety Administration (NHTSA) concerning the public dissemination of defect and noncompliance information by press release prior to a manufacturer's notification as required by Part 577, *Defect and Noncompliance Notification*. In your letter, you refer to a press release issued by the agency concerning defects in some of your vehicles. This release was made prior to your providing notification to the vehicle owners.; The NHTSA through Part 577 requires that manufacturers provid notification to the owners of vehicles involved in defect or noncompliance recalls. This notification must be provided, in the case of a manufacturer- initiated recall, within a 'reasonable time' after a manufacturer discovers the existence of a defect or noncompliance. You conclude that the publication of an agency press release prior to the time that a manufacturer notifies owners of a defect or noncompliance in effect shortens the 'reasonable time' allowed for such notification. This in turn, you suggest, results in unnecessary public concern before the manufacturer is capable of implementing the recall.; The publication of an agency press release does not shorten the tim period allotted a manufacturer under Part 577 for providing notification. A manufacturer is still permitted a 'reasonable time' to comply with the requirements. The NHTSA has adopted the 'reasonable time' approach to manufacturer notification of owners, because it realizes that the amount of preparation to conduct a recall may vary depending upon the complexity of the defect or noncompliance.; The agency operates under different timing considerations than thos applicable to a manufacturer. The NHTSA is under a mandate to ensure that vehicles containing potentially dangerous defects or noncompliances are corrected or removed from highway service as soon as possible. The agency understands that any recall and remedy process is somewhat time- consuming for a manufacturer, and accordingly, vehicles will not be repaired immediately. Therefore, in the interim time between a manufacturer's discovery of a defect or noncompliance and his notice and remedy, the agency must issue warnings to vehicle owners so that they can take the appropriate action. Such action might include checking their vehicle for possible signs of failure or discontinuance of use of the affected vehicle.; In summation, the agency must balance the manufacturer's need for reasonable time to notify and remedy with the vehicle owner's need for immediate information pertaining to any potential safety problems. This balance has taken the form of the NHTSA's issuance of a warning pending a manufacturer's issuance of notification. The NHTSA concludes that through this mechanism safety is preserved and manufacturers are not unduly burdened.; Sincerely, Joan Claybrook |
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ID: aiam5521OpenMr. Jeffrey Echt President, Saline Electronics, Inc. 13379 Michael Road Highland, IL 62249; Mr. Jeffrey Echt President Saline Electronics Inc. 13379 Michael Road Highland IL 62249; "Dear Mr. Echt: We have received your letter of March 10, 1995, askin whether it is permissible under Standard No. 108 to use the hazard warning lamps as a deceleration warning system. Paragraph S5.5.10(a) states that 'Turn signal lamps, hazard warning signal lamps, and school bus warning lamps shall be wired to flash.' With this in mind, 'and the fact that hazard warning indicators are commonly used to warn high-speed trailing traffic that a leading vehicle or vehicles are moving slowly or stopped', you have asked: '1. Would a device which automatically activated a vehicle's hazard warning system at the onset of high, braking induced deceleration and deactivated the hazard warning system upon release of the brake pedal (following automatic activation) be permissible under FMVSS 108? This assumes that the device will not prevent activation or cause deactivation of the hazard warning system if the mandatory vehicular hazard warning signal operating unit has been activated by the driver.' Heretofore, the agency's opinion letters on deceleration warning systems have covered those that operate through lamps that are steady burning in use (to Norman H. Dankert on June 3, 1990, and to Bob Abernethy on September 7, 1990), or through original equipment lamps that are additional to those required by the standard (letter of July 30, 1993, to the Commonwealth of Virginia). In those instances, we have advised that a deceleration warning system must be steady burning in use. Your question raises the issue of whether a flashing deceleration warning system is acceptable if it operates through original equipment lamps that are intended to flash when they are used. Flexible asked a similar question with respect to a supplementary lighting system. We advised it (letter of December 8, 1986) that simultaneous use of flashing and steady-burning lamps have the potential for creating confusion in vehicles to the rear and impairing the effectivess of the required stop lamps within the meaning of S5.1.3 (the provision of Standard No. 108 that governs the permissibility of supplemental original lighting equipment). We believe that the same conclusion also applies to wiring the hazard warning system to operate as a high deceleration warning system as well. Thus, we do not view this system as permissible under Standard No. 108. Obviously, complying vehicles are manufactured so that it is possible for a driver to simultaneously activate the hazard warning system and stop lamp system. However, we believe that this happens infrequently, and when it does, it is a conscious choice of the operator and not of a system. Because of the conclusion we have reached above, your second question is moot. Sincerely, Philip R. Recht Acting Chief Counsel"; |
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ID: aiam5523OpenMr. Jeffrey Echt President, Saline Electronics, Inc. 13379 Michael Road Highland, IL 62249; Mr. Jeffrey Echt President Saline Electronics Inc. 13379 Michael Road Highland IL 62249; "Dear Mr. Echt: We have received your letter of March 10, 1995, askin whether it is permissible under Standard No. 108 to use the hazard warning lamps as a deceleration warning system. Paragraph S5.5.10(a) states that 'Turn signal lamps, hazard warning signal lamps, and school bus warning lamps shall be wired to flash.' With this in mind, 'and the fact that hazard warning indicators are commonly used to warn high-speed trailing traffic that a leading vehicle or vehicles are moving slowly or stopped', you have asked: '1. Would a device which automatically activated a vehicle's hazard warning system at the onset of high, braking induced deceleration and deactivated the hazard warning system upon release of the brake pedal (following automatic activation) be permissible under FMVSS 108? This assumes that the device will not prevent activation or cause deactivation of the hazard warning system if the mandatory vehicular hazard warning signal operating unit has been activated by the driver.' Heretofore, the agency's opinion letters on deceleration warning systems have covered those that operate through lamps that are steady burning in use (to Norman H. Dankert on June 3, 1990, and to Bob Abernethy on September 7, 1990), or through original equipment lamps that are additional to those required by the standard (letter of July 30, 1993, to the Commonwealth of Virginia). In those instances, we have advised that a deceleration warning system must be steady burning in use. Your question raises the issue of whether a flashing deceleration warning system is acceptable if it operates through original equipment lamps that are intended to flash when they are used. Flexible asked a similar question with respect to a supplementary lighting system. We advised it (letter of December 8, 1986) that simultaneous use of flashing and steady-burning lamps have the potential for creating confusion in vehicles to the rear and impairing the effectivess of the required stop lamps within the meaning of S5.1.3 (the provision of Standard No. 108 that governs the permissibility of supplemental original lighting equipment). We believe that the same conclusion also applies to wiring the hazard warning system to operate as a high deceleration warning system as well. Thus, we do not view this system as permissible under Standard No. 108. Obviously, complying vehicles are manufactured so that it is possible for a driver to simultaneously activate the hazard warning system and stop lamp system. However, we believe that this happens infrequently, and when it does, it is a conscious choice of the operator and not of a system. Because of the conclusion we have reached above, your second question is moot. Sincerely, Philip R. Recht Acting Chief Counsel"; |
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ID: aiam1464OpenMr. R. Debesson, General Secretary, European Tyre and Rim Technical Organisation, Avenue Brugmann, 32, 1060 Bruxelles, BELGIUM; Mr. R. Debesson General Secretary European Tyre and Rim Technical Organisation Avenue Brugmann 32 1060 Bruxelles BELGIUM; Dear Mr. Debesson: This is in reply to your Submission Nos. 78 and 79, of February 1 1974, and February 19, 1974, respectively. In Submission No. 79 you request that several corrections be made to the Tables of the Appendices of Standard Nos. 109 and 110 as they appeared in the *Federal Register* on November 1, 1973 (38 FR 30234). In Submission No. 78 you request new additions to the Tables.; You request in Submission No. 79 that Footnote No. 1 of Table I-S an I-T in standard No. 109 be corrected. A correction of those footnotes was published in the *Federal Register* on February 5, 1974 (39 FR 4578), and we enclose a copy. You also request that in Table I-C of Standard No. 109 the test rim width for the 165-15 tire size designation be changed to 4 1/2 inches. That correction was published in the *Federal Register* of November 13, 1973 (38 FR 31309), copy also enclosed.; You further request that Table I-D be corrected by changing the tes rim width of the 145-10 tire size designation to 4 1/2 inches, by changing the minimum size factor of the 230-15 tire size designation to '37.30,' and by changing the test rim width of the 165-400 tire size designation to '4.65.' Our review of previous publications show these three items and we will publish a correction regarding them. You also request changed in several load inflation values in Tables I-H and I-N. The November 1, 1973, publication is incorrect with respect to these load values as well, and we will publish a correction regarding them.; We cannot, however, grant your request that we correct in Table I-F th 16 psi (from '705 to '760') for the 5.60 R 15 and 5.90 R 13 tire size designations without first receiving a formal submission from E.T.R.T.O. requesting the change. The 705-pound load is a carryover from earlier Tables, and we cannot conclude that the Table as published on November 1 is in error. Accordingly, if you wish the load value to be modified to 760 pounds you must request such a change in accordance with the abbreviated rulemaking procedures published in the *Federal Register* on October 5, 1968 (33 FR 14964). Upon receipt and approval of E.T.R.T.O.'s submission, we will make the requested change in the subsequent quarterly amendment to the Tables.; You ask in Submission No. 78 that we add to Table I-H the 165 SR 1 tire size designation and the alternate rim size 500b. No amendment is necessary to include the 165 SR 13 tire size designation in Table I-H. Tire size 165 R 13 is listed, and Footnote 1 of the Table allows the 'S' to be placed adjacent to the 'R.' We will, however, add the 5.00B rim as an alternative rim size for the 165 R 13 tire size designation in the next quarterly amendment to the Tables.; We are pleased to be of assistance. Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam5599OpenSteven B. Fisher, Esq. Kostow & Daar, P.C. 200 South Wacker Drive Chicago, Illinois 60606; Steven B. Fisher Esq. Kostow & Daar P.C. 200 South Wacker Drive Chicago Illinois 60606; Re: Motor Vehicle Safety Standard No. 108 Dear Mr. Fisher: Thi responds to your letter of July 31, 1995, to Philip R. Recht, formerly Chief Counsel of this agency. You have asked several questions relating to use of the word 'practicable' in the lamp location requirements of Federal Motor Vehicle Safety Standard No. 108. Your first question is 'with respect to truck, trailer identification lights (red), what is meant exactly by `practicable' as used in SS5.3.1.1 and 5.3.1.4.' Your second question is whose responsibility it is to make the determination of practicability. Your final question is whether there is any way for a manufacturer of 'a single rear identification light' to know where a trailer manufacturer will install the product on any given trailer. We don't see the word 'practicable' in S5.3.1.1. However, S5.3.1.4 does provide that rear clearance lamps need not meet the requirement of Table II that they 'be located as close as practicable to the top of the vehicle' when the rear identification lamps are located at the extreme height of the vehicle. Table II specifies location of lighting equipment on the vehicle, and it is therefore the responsibility of the vehicle manufacturer, in certifying that its vehicle complies with all applicable Federal motor vehicle safety standards, to determine what is practicable. As you indicate, a trailer manufacturer may make such a determination 'in light of the particular design/configuration of the trailer involved.' NHTSA will not contest this determination unless it is clearly erroneous. In short, 'practicable' as meant by S5.3.1.4 or any other place where the word occurs, is not a term defined by Standard No. 108, and derives its meaning from specific factual contexts. We note that the Random House Dictionary of the English Language (1967) defines 'practicable' as 'capable of being done, effected, or put into practice with the available means' (p. 1127). There is no responsibility under Standard No. 108 for the manufacturer of identification lamps to know where its products will be installed on the motor vehicle. Its responsibility under Standard No. 108 is to ensure that any identification lamp that it manufactures for replacement purposes is designed to conform to Standard No. 108's performance specifications and so certified at the time the lamp is shipped from the factory. If you have any further questions you may phone Taylor Vinson of this office (202-366-5263). Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam3361OpenMr. T. M. Birdwell, General Electric Company, Silicone Products Division, 9119 Gaither Road, Gaithersburg, Maryland 20760; Mr. T. M. Birdwell General Electric Company Silicone Products Division 9119 Gaither Road Gaithersburg Maryland 20760; Dear Mr. Birdwell: This responds to your letter of July 30, 1980, concerning Federal Moto Vehicle Safety Standard 116, in which you inquired about the definition of 'purple' as specified for the color of DOT 5 brake fluid. During a telephone conversation regarding the question on September 2, 1980, with Edward Glancy of this office, you suggested that specific color coordinated be established and expressed concern about another manufacturer's DOT 5 brake fluid that appears to be blue rather than purple.; Paragraph S5.1.14 of the standard states: 'Brake fluid and hydrauli system mineral oil manufactured on or after September1, 1978, shall be of the color indicated:... DOT 5 -- purple.' This is in contrast to the color specification of DOT 3 nd DOT 4 brake fluid which are required to be colorless to amber and hydraulic system mineral oil which is required to be green.; The major purpose of the color coding requirements is to permit eas identification of fluids before they are placed in a vehicle, in order to prevent the mixing of an incompatible fluid in a braking system. See notice 12 of Docket 71-13, published in the Federal Register (41 FR 54942, 54943) on December 16, 1976. At an early stage in the rulemaking process, the Agency did propose color requirements defined in terms of millimicrons. See notice 5 of Docket 71-13, published in the Federal Register (i38 FR 32142, 32144) on November 21, 1973. (The colors proposed at that time were later changed.) Later, however, the Agency determined that visual inspection for color compliance was adequate and the proposed wavelength bands were deleted. See notice 6 of Docket 71-13, published in the Federal Register (39 FR 30353) on August 22, 1974.; As you noted in your letter, Notice 10 of Docket 71-13, published i the Federal Register 40 FR 56928) on December 5, 1975, does explain:; >>>...The specifications for fluid color are intended to refer to colo ranges as generally interpreted in daylight by persons of normal color vision. No color coordinates are proposed, since the fluids may change color in storage or in use (without detriment to the performance of the fluids).<<<; Establishing specific color coordinates would require rulemakin proceedings in accordance with agency regulations. If you believe that coordinates ought to be established, you may wish to consider submitting a petition for rulemaking to amend FMVSS 116. The procedures for submitting such a petition are set forth at 49 CFR Part 552. If you should submit a petition, we would like to see it address the issue of why visual inspection for color compliance is inadequate and what type of definition should be established.; If you believe that another manufacturer is in noncompliance wit Standard 116, we suggest that you send the relevant information to our Office of Vehicle Safety Compliance for enforcement purposes.; We have enclosed copies of the Federal Register notices referred to b this letter.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0101OpenMr. R. J. Hart, Bugetta Inc., 3037 Enterprise Avenue, Costa Mesa, CA 92626; Mr. R. J. Hart Bugetta Inc. 3037 Enterprise Avenue Costa Mesa CA 92626; Dear Mr. Hart:#With reference to your letter of August 14 and it enclosed specification sheet covering the Bugetta, this vehicle appears to be a 'multipurpose passenger vehicle' for purpose of the Federal motor vehicle safety standards since it is constructed with features for occasional off road use.#Your understanding of the applicability of standards to multipurpose passenger vehicles is correct. We concur with your view that compliance with Standard No. 103 (Windshield Defrosting and Defogging) is a meaningless requirement for a vehicle with no top or windows.#Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations; |
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ID: aiam1173OpenMr. Dennis E. David, Legislative Coordinator, Kawasaki Motors Corporation, 1062 McGaw Avenue, Post Office Box 11447, Santa Ana, California 92711; Mr. Dennis E. David Legislative Coordinator Kawasaki Motors Corporation 1062 McGaw Avenue Post Office Box 11447 Santa Ana California 92711; Dear Mr. David: In your letter of June 21, 1973, to Mr. Schneider, you ask whethe Standard No. 123 precludes use of a device that, when activated, does not allow and automatic return of the throttle to idle.; "As you have observed, Standard No. 123 specifies that if a twist-gri throttle is provided, its manner j of operation shall be 'self-closing to idle ... after release of hand.' This requirements is without qualification and means that at any time the operator's hand is removed from the throttle, the throttle shall automatically return to idle. Therefore, a motorcycle equipped with the device you describe would not comply with Standard No. 123."; Yours truly, Assistant Chief Counsel |
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ID: aiam1180OpenMr. Gil W. Bellamy, Administrator, Oregon Traffic Safety Commission, Room 313, Highway Building, Salem, OR 97310; Mr. Gil W. Bellamy Administrator Oregon Traffic Safety Commission Room 313 Highway Building Salem OR 97310; Dear Mr. Bellamy: Thank you for the copy of Oregon House Bill 2721 that you enclosed i your letter of June 25, 1973. We have reviewed it carefully, and have concluded that virtually all of Section 2 is preempted by 15 U.S.C. 1392(d) (copy enclosed).; As you may know, this section of the National Traffic and Motor Vehicl Safety Act prohibits a State from having a safety standard applicable to the same aspect of performance as a Federal safety standard unless it is identical to the Federal standard. In this instance, the relevant Federal standard is 49 CFR S571.108 Standard No. 108, *Lamps*, *reflective devices*, *and associated equipment*.; Section 2 of HB 2721 requires motor vehicles manufactured after Octobe 1, 1975, to be equipped with a green-yellow-red rear mounted lighting system. The NHTSA considers Standard No. 108 to include within its scope all lighting equipment required to be used on the rear of motor vehicles to which it applies. Any State requirements that have the effect of regulating such equipment must therefore be identical to the relevant provision of Standard No. 108. Section 2 of HB 2721 is not identical to the Federal standard relating to that aspect of performance, and must therefore be considered as invalidated as that category of vehicle is expressly excluded from Standard No. 108. Portions of Section 3 (ORS 483.412(3) (a) and (b)) are invalidated for the same reason. The remainder of Section 3 and Section 4 does not conflict with the relevant provisions of Standard No. 108.; The guiding principle that we have applied to this situation is tha the State requirements that regulate the design of motor vehicles must be identical to the Federal standards. It was clearly the intent of Congress to provide for uniformity of regulation of the manufacturer in areas where the Federal agency has acted, and they did so by the identity requirements of section 1392(d).; Sincerely, James E. Wilson, Associate Administrator, Traffic Safet Programs; |
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ID: aiam3497OpenMr. Kenneth G. Moyer, 6400 Goldbranch Road, Columbia, SC 29206; Mr. Kenneth G. Moyer 6400 Goldbranch Road Columbia SC 29206; Dear Mr. Moyer: This is in reply to your letter of September 22, 1981, about you 'alert device which automatically turns on the stop lamps of the vehicle when the accelerator is released.' You wish our permission to install the device for experimentation and testing on other vehicles, as well as an interpretation of Federal Motor Vehicle Safety Standard No. 108 whether your device is allowable.; As you know, the agency has devoted considerable effort to improve rea braking signals, culminating in its proposal that passenger cars be equipped with a single high- mounted stop lamp on the centerline of the vehicle. The concept of a pre-brake application signal is a familiar one to us, but the agency has conducted no formal research with respect to it, and in view of its stop-lamp proposal, is unlikely to do so. The technical issues that we consider relevant to your concept are (1) whether most rear-end accidents are preceded by a 'panic' stop by the struck vehicle, (2) whether panic stops involve unique driver behavior that can be reliably discriminated from non-panic stop behavior and used to trigger a pre-braking signal, and (3) whether the resulting signal will automatically result in a decrease in the reaction time of following drivers that is equal to the early warning time it provides. We know of no scientifically acceptable data that support these critical assumptions. We are especially concerned that a high rate of 'false alarms' may lead to a decrease in the overall warning value of the stop lamp signal itself, i.e., the 'cry wolf' phenomenon. This could lead to a significant reduction in the effectiveness of any proposed system.; Paragraph 2.1 of SAE Standard J586d, *Stop Lamps*, September 1977 incorporated by reference in Standard No. 108, defines a stop lamp as one whose operation indicates 'the intention of the operator of a vehicle to stop or diminish speed by braking.'; Your device would activate the stop lamp under a condition indicatin an intent other than the above, which could impair the effectiveness of the stop lamps. We view any use of required lighting equipment for a purpose other than as defined, as an 'impairment' within the prohibition of paragraph S4.1.3 of Standard No. 108 if the device is installed as original equipment. If the device is sold in the aftermarket, our laws preclude modifications that 'render ineffective in whole or in part' required lighting equipment, if the modifications are performed by a person other than the vehicle owner. We would consider your system prohibited by this provision as well.; Noting your comment that the device may be used for testing on schoo buses, this means that there is no prohibition under the laws that we administer which would forbid a school district from installing your device on its fleet. Such a modification would be subject to laws of the jurisdiction in which the school bus is registered and operates.; 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.