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: aiam1894OpenMr. William A. Domm, International Harvester, 401 North Michigan Avenue, Chicago, IL 60611; Mr. William A. Domm International Harvester 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Domm: This is in response to your letter of March 26, 1975, asking that th National Highway Traffic Safety Administration (NHTSA) concur in your preliminary decision to classify two new International Harvester vehicles as multipurpose passenger vehicles.; The definition of multipurpose passenger vehicle, which appears at 4 CFR Part 571.3 *definitions*, describes vehicles falling within that category as ones with motive power, except trailers, designed to carry 10 persons or less and constructed either on a truck chassis or with special features for occasional off-road operation.; According to your letter, the two vehicles in question satisfy both th truck chassis and the features for occasional off-road use criteria. If this is the case, and the other specified criteria are met as well, your vehicles would be properly classified as multipurpose passenger vehicles for purposes of complying with applicable motor vehicle safety standards.; The NHTSA is not in a position to formally endorse your classification However, it appears from the information you have provided that the vehicles in question are multi-purpose passenger vehicles as defined in Part 571.3 (sic); Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0786OpenMr. Louis C. Lundstrom, Director, Automotive Safety Engineering, Environmental Activities Staff, General Motors Technical Center, Warren, MI 48090; Mr. Louis C. Lundstrom Director Automotive Safety Engineering Environmental Activities Staff General Motors Technical Center Warren MI 48090; Dear Mr. Lundstrom: Your letter of July 11, 1972, raises two substantive question concerning the belt system requirements of Motor Vehicle Safety Standard No. 208.; The first question concerns S7.4.1, which provides that the engin starting system shall not be operable 'unless the belt system at each occupied front position is operated after the occupant is seated.' You ask whether a system that you submitted for our inspection, which does not use electronic logic circuits, would conform to this requirement.; The belt system in question is designed to make it quite difficult t enter the vehicle if the belt system is fastened. The occupant is thus forced to unfasten the belt (if it has been left fastened) to enter the vehicle, then to fasten it in order to start the engine. The system employs an inboard- mounted shoulder belt with the outboard attachment point for the lap and shoulder belts mounted in the door. The ignition system employs a buckle switch, so that the belt must be buckled for the engine to start. Upon entering the vehicle, an occupant may find that the belt is either buckled or unbuckled, depending on the action of the previous occupant, but if it is buckled, he will find entry difficult if he does not first unbuckle it. After evaluating the system, we have concluded that the occupant is essentially compelled to operate the belt system after being seated in order to start the car. The system therefore conforms to the requirements of S7.4.1.; In view of the lack of logic circuits, we urge that the design of th buckle be given careful attention, to prevent defeat of the system by the insertion of objects into the buckle.; Your second question concerns the acceptability of belts which requir 'some action during normal vehicle entry or egress' under the requirements for passive belts. As presently drafted, S4.5.3 does not permit such belts to be classified as passive belts. We will treat your request for amendment of this requirement as a petition for rulemaking and give it prompt consideration.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam3903OpenMr. Ron Marion, Specification Engineer, Thomas Built Buses, Inc., P.O. Box 2450, High Point, NC 27261; Mr. Ron Marion Specification Engineer Thomas Built Buses Inc. P.O. Box 2450 High Point NC 27261; Dear Mr. Marion: This responds to your letter regarding Federal Motor Vehicle Safet Standard No. 222, *School Bus Seating and Crash Protection*. You asked whether a single, full width, 90 inch seat may be placed at the last row of the school bus and be designated as a four passenger seat. In telephone calls with Ms. Hom of my staff, you stated that these school buses have a gross vehicle weight rating greater than 10,000 pounds. Further, the next to last row of seats has two 39 inch, three passenger seats, on the left and right of the aisle.; I would like to separate your question into two parts. The first par deals with designating the full width seat as a four passenger seat even though, under S4.1 of Standard No. 222, the number of seating positions is six. The second part concerns the restraining barrier requirement of Standard No. 222.; We believe that designating a 90 inch, full width seat as a fou passenger seat would not comply with FMVSS No. 222. Paragraph S4.1 of the standard states that:; >>>The number of seating positions considered to be in a bench seat i expressed by the symbol W, and calculated as the bench width in inches divided by 15 and rounded to the nearest whole number.<<<; Thus, under S4.1, the number of seating positions on a 90 inch widt seat is six. Labeling a 90 inch width seat as a four passenger seat amounts to a disclaimer by the manufacturer that two seating positions are not to be used. This practice is prohibited since, despite the disclaimer, it is likely that passengers will use all six seating positions and, thus, each position should provide the level of occupant protection required by our standard. A manufacturer cannot escape its occupant protection responsibilities associated with a designated seating position simply by disclaiming that position.; The second part of your question deals with designating the 90 inc seat as a six passenger seat and the requirement in Standard No. 222 for restraining barriers. Standard No. 222 requires a restraining barrier of specified size in front of any designated seating position that does not have the rear surface of another school bus passenger seat within 24 inches of its seating reference point (SRP). From the information in your letter, we have determined that at least one of the designated seating positions in the center portion of the last row would not have the rear surface of another passenger seat within 24 inches of its SRP. A restraining barrier would have to be placed in front of these designated seating positions, and would block the center aisle. Such a barrier would obstruct access to the emergency exits.; FMVSS No. 217, *Bus Window Retention and Release*, regulates th number, size, and operation of school bus emergency exits. Paragraph S2 states that one of the purposes of Standard No. 217 is 'to provide a means of readily accessible emergency egress.' Paragraph S5.2.3.1 requires each school bus to be equipped with either a rear emergency door or a side emergency door and a rear window. Paragraphs S5.2.3.1 and S5.4 require unobstructed passage through these exits from the interior of the bus. If there is unobstructed access, as required by paragraphs S5.2.3.1 and S5.4, with the restraining barrier in place, then the buses you describe would not violate that requirement. However, even if the barrier and other aspects of the bus design would not violate the requirement, we would urge that the manufacturers of such buses ensure that the design not complicate efforts of the passengers to reach and use the emergency exits.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2611OpenHonorable Joseph L. Fisher, 19 East Market Street, Leesburg, VA 22075; Honorable Joseph L. Fisher 19 East Market Street Leesburg VA 22075; Dear Mr. Fisher: This responds to your February 16, 1977, letter asking whether day car centers are required to purchase buses manufactured in conformance with the school bus safety standards.; The National Highway Traffic Safety Administration has decided that th inclusion of day care centers within the definition of 'school', for purposes of applying the school bus safety standards, would be inappropriate at this time. After careful deliberation, the agency has concluded that since the school bus safety standards do not specifically refer to day care centers, cay care center operators may not have been aware of the possibility that vehicles they use might be subject to school bus safety requirements. Therefore, persons interested in that issue may not have fully participated in our earlier rulemaking on the subject.; In accordance with accepted rulemaking procedures, the agency intend to issue a proposal to extend the coverage of the school bus standards to buses purchased by day care centers. This proposal will provide an opportunity for persons interested in the operation of these facilities to comment upon the advisability of extending the school bus safety standards to their vehicles.; I appreciate your interest in this issue and apologize for an inconvenience caused to your constituent by the length of time required to make this decision.; Sincerely, Joan Claybrook |
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ID: aiam0339OpenMarion C. Denton, Marden Manufacturing Company, 205 Denton Avenue, Auburndale, FL 33823; Marion C. Denton Marden Manufacturing Company 205 Denton Avenue Auburndale FL 33823; Dear Mr. Denton: This is in reply to your letter of May 3, 1971, requesting a interpretation of the Tire Identification and Record Keeping Regulation. You indicated in your letter that you are a trailer manufacturer. As such, you are considered a motor vehicle manufacturer under both the regulation and section 102(3) and (5) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1381 *et seq*.) (copies enclosed).; As a manufacturer, you are required, by section 113(f) of the Act, t record the name and address of the first purchaser for purposes other than resale. Section 574.10 of the regulation requires that you maintain a record of the tires shipped on or in vehicles which you manufacture. In the event of a defect notification concerning either the vehicle or its tires, your responsibilities are enumerated in section 111 and 113 of the Act.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam2304OpenHonorable James L. Buckley, United States Senate, Washington, DC 20510; Honorable James L. Buckley United States Senate Washington DC 20510; Dear Senator Buckley: This is in response to your letter of May 11, 1976, forwarding petition from Gulf + Western Manufacturing Company for reconsideration of the bumper standard recently issued as Part 581 of Title 49 Code of Federal Regulations.; A number of requests for our view on the Gulf + Western petition hav been forwarded by members of Congress who have received copies of the Gulf + Western petition accompanied by a letter from Mr. James A. Graham.; It is the National Highway Traffic Safety Administration's policy t issue a notice of action taken on petitions for reconsideration within 120 days after publication of the final rule, unless action within that time is impracticable. Since the agency is currently in the process of considering the petitions received, it would not be appropriate for us to comment at this time on the remarks made by Gulf + Western.; I assure you that Gulf + Western's comments and the informatio contained in all of the petitions for reconsideration will receive thorough consideration. The agency's response to the petitions will be published in the *Federal Register*.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0293OpenMr. Y. Takami, Engineer, Toyo Tire (U.S.A.) Corporation, 3136 East Victoria Street, Compton, CA 90221; Mr. Y. Takami Engineer Toyo Tire (U.S.A.) Corporation 3136 East Victoria Street Compton CA 90221; Dear Mr. Takami: This is in reply to your letter of February 2, 1971, to Mr. Casanov concerning Part 574 - Tire Identification and Record Keeping.; Adding a group of numbers consisting of three-digits to the tir identification number is not permitted under the regulation because the additional numbers would be too easily confused with the tire identification number.; You are not prohibited, however, from placing the additiona three-digit number elsewhere on the tire in an area where it would not be confused with the required tire identification number. Anywhere further than six inches would be far enough to avoid confusion.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam3846OpenMr. Masakatsu Kano, Executive Vice President, MMC Services Inc., Suite 1960, 3000 Town Center, Southfield Michigan 4805; Mr. Masakatsu Kano Executive Vice President MMC Services Inc. Suite 1960 3000 Town Center Southfield Michigan 4805; Dear Mr. Kano: This responds to your letter of April 13, 1984, addressed to Mr. Roma Brooks of NHTSA's Office of Enforcement. You stated that you were submitting the letter 'to assure that the Agency and Mitsubishi agree in writing as we did verbally' concerning the compliance of a proposed electronic odometer design with Standard No. 101, *Controls and Displays.* You also stated that lead time dictates an imminent decision on design plans, that the agency's early approval/response' to your selected solution is greatly appreciated, and that if you do not hear to the contrary within 30 days, you will assume the agency's concurrence. As discussed below, your letter indicates a serious misunderstanding of both Federal statutory requirements and NHTSA policies and procedures. Moreover, your apparent interpretation of Standard No. 101 is incorrect.; First, NHTSA does not grant approval of motor vehicle or motor vehicl equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to assure that its vehicles or equipment comply with applicable requirements.; NHTSA is willing to provide interpretations and opinions in response t reasonable requests. However, such interpretations and opinions are only provided in writing and only by NHTSA's Chief Counsel. The agency does not consider itself bound by verbal statements made by agency employees or by interpretations made by persons other than the Chief Counsel.; Moreover, NHTSA does not offer interpretations by remaining silent i response to letters which assert that such silence is assumed to be concurrence. The agency considers the inclusion of such purported conditions to be inappropriate and does not consider itself bound by them.; The agency regrets if Mr. Brooks' conversation contributed to th misunderstandings apparent in your letter. In the future, questions of interpretations should be addressed in writing to the Chief Counsel.; Your question of interpretation concerns a proposed design for a electronic odometer which would display either miles or kilometers. The following represents our opinion based on the facts provided in your letter.; According to your letter, the vehicle's speedometer would display, a the option of the driver, in either miles per hour or kilometers per hour. The selected unit of measure would be identified by a lighted display reading either 'MPH' or 'Km/h'. The digits of the odometer would correspond to the units of measure selected for the speedometer, but the odometer itself would not identify its units of measure. As discussed below, such a design would not meet the requirements of Standard No. 101, since that standard requires an odometer that indicates kilometers to be identified by 'KILOMETERS' or 'km'.; Section S5 of Standard No. 101 requires that 'each passenger car multi-purpose passenger vehicle and truck or bus less than 10,000 pounds GVWR with any display listed in S5.1 or in column 1 of Table 2, shall meet the requirements of this standard for the location, identification, and illumination of such control or display.' Odometers are one of the display listed in column 1 of Table 2.; Section S5.2.3 references the requirements of Table 2. Footnote 3 o Table 2 specifies the following requirements for odometers:; >>>If the odometer indicates kilometers, then 'KILOMETERS' [or] 'km shall appear, otherwise no identifications is required.<<<; Section S5.2.3 further provides that '[t]he identification required o permitted by this section shall be placed on or adjacent to the display that it identifies.; Standard No. 101 thus requires odometers indicating kilometers to b identified by 'KILOMETERS' or 'km', and such identification must be placed on or adjacent to the odometer. Since your proposed design would indicate kilometers, it would be necessary to identify its units of measure according to these requirements.; I would note that these requirements cannot be met merely by placin the odometer adjacent to the speedometer. While the identification of the selected units of measure for the speedometer could be placed adjacent to both the speedometer and odometer, the identification requirements are different for the two displays. Table 2 requires that a speedometer graduated in miles per hour and kilometers per hour be identified by 'MPH and km/h' in any combination of upper or lower case letters. As discussed above, the requirement for odometers is 'KILOMETER' or 'km'. A single identification of units of measure cannot meet these requirements simultaneously.; Please note that this opinion is limited to the specific issue raise by your letter and does not consider whether the proposed design would otherwise meet the requirements of Standard No. 101.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5091OpenMr. Chester I. Nielsen, III Vice President Sales Wesbar Corporation P.O. Box 577 West Bend, WI 53095; Mr. Chester I. Nielsen III Vice President Sales Wesbar Corporation P.O. Box 577 West Bend WI 53095; Dear Mr. Nielsen: This responds to your letter of October 21, 1992, t Walter B. McCormick, Jr. (the General Counsel of this Department). You have written for 'further explanation of S5.3.1.1.1 in FMVSS 108.' You have heard that there is an additional interpretation with respect to the location of clearance lamps on boat trailers whose overall width is 80 inches or more, which would allow mounting of these lamps in accordance with a sketch that you enclosed, and you ask for confirmation of this interpretation. We are unaware of any interpretation of this nature. The requirements for the provision and location of clearance lamps on wide boat trailers remain those set forth in Tables I and II of Standard No. 108, with the exceptions set forth in paragraphs S5.1.1.9, S5.3.1.1.1, and S5.3.1.4. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0769OpenMr. D. P. Peck, The Standard-Triumph Motor Co., Ltd., Coventry, England; Mr. D. P. Peck The Standard-Triumph Motor Co. Ltd. Coventry England; Dear Mr. Peck: This is in reply to your letter of June 28, 1972, in which yo requested formal confirmation of the interpretation of S4.3(c) of Motor Vehicle Safety Standard No. 209 given you informally on June 22.; The requirements of S4.3(c) apply to bolts used to secure the pelvi restraint of a seat belt assembly. They do not apply to bolts used to secure the upper torso restraint. Bolts for the upper torso restraint are therefore regulated with respect to their strength only by the assembly performance requirements of S4.4(b).; The reference to shoulder bolts' in S4.3(c) relates to the design o the bolt and not to the manner of its use. Pelvic restraints are often attached to the vehicle by such bolts, hence the reference to them.; Sincerely, Richard B. Dyson, Assistant 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.