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: aiam1779OpenMr. Danny J. Lanzdorf, Supervising Engineer, Oshkosh Truck Corporation, P.O. Box 560, Oshkosh, WI 54901; Mr. Danny J. Lanzdorf Supervising Engineer Oshkosh Truck Corporation P.O. Box 560 Oshkosh WI 54901; Dear Mr. Lanzdorf: This responds to Oshkosh Truck Company's January 9, 1975, questio whether Standard No. 121, *Air brake systems*, permits the installation of a hand-operated control lever for use in modulating the air in the service brake system in a vehicle which is equipped with a foot-operated service brake control which meets the requirements of the standard.; Standard No. 121 does not include a requirement for a service brak control, and it does not prohibit installation of more than one service brake control. At the same time, several provisions are based on operation of the service brake control(e.t., S5.3.1, S5.7.2.1) and therefore indirectly require a service brake control with certain characteristics. Recently-issued amendments of the emergency brake provisions (effective September 1, 1976) are intended to combine service and emergency brake control in a single service brake control to simplfy (sic) and standardize braking in all new vehicles.; With this in mind, the NHTSA has determined that installation of hand-operated control lever such as you describe does not violate the standard. It may be advisable however, to label this hand-operated lever with a designation other than 'service brake control.' The NHTSA will review this and the other provisions of Standard No. 121 on a continuing basis to determine the advisability f further specifications in the future.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4594OpenRobert C. Craig Quality Control Manager Cosco, Inc. 2525 State Street Columbus, IN 47201; Robert C. Craig Quality Control Manager Cosco Inc. 2525 State Street Columbus IN 47201; "Dear Mr. Craig: This responds to your February 3, 1989 letter to Mr George Parker, our Associate Administrator for Enforcement, seeking an interpretation of Standard 213, Child Restraint Systems (49 CFR /571.213). Specifically, paragraph S5.5 of that standard requires each child restraint system to be permanently labeled with certain specified information. One of the items of information required to be permanently labeled on the child restraint is the manufacturer's recommendations for the maximum weight and height of children who can safely occupy the system, and those weight and height recommendations must be expressed in English units (pounds and inches). Your letter stated that your company would like to express its maximum weight and height recommendations in both English units and equivalent metric units (kilograms and meters), and asked whether this would be permitted by Standard 213. As long as the information is presented in a manner that is not likely to cause confusion, Standard 213 does not prohibit manufacturers from expressing required information in equivalent English and metric units. For each of the labeling requirements set forth in NHTSA's regulations, this agency has consistently taken the position that manufacturers may present information in addition to the required information, provided that the additional information is presented in a manner that is not likely to confuse the user. Moreover, the agency has already concluded that passenger car tires may be labeled with required information expressed in equivalent English and metric units. See the enclosed April 5, 1979 letter to Mr. Michael Petler. We would apply the same reasoning in interpreting the labeling requirements of Standard 213. That is, Standard 213 permits manufacturers to present the required information in both English and metric units, provided that the information is presented in a manner that is not likely to confuse persons using the child restraint system. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam3251OpenMr. Don Gerken, Product Engineer, Cosco Home Products, 2525 State Street, Columbus, IN, 47201; Mr. Don Gerken Product Engineer Cosco Home Products 2525 State Street Columbus IN 47201; Dear Mr. Gerken: This responds to your letter of March 27, 1980, to Mr. Stephen Oesch o my staff concerning Standard No. 213, *Child Restraint Systems*. You asked whether the labels and installation diagrams required by the standard must comply with Standard No. 302, *Flammability of Interior Materials*. In addition, you asked whether an upholstery tag, required by State law, attached to the seat must comply with Standard No. 302.; Section 5.7 of Standard No. 213 requires 'each material used in a chil restraint system' to conform to the performance requirements of Standard No. 302. Because the label, installation diagram and tag materials are affixed to the child restraint, they would have to comply with Standard No. 302.; Section 4.2.2 of Standard No. 302 provides that 'any material tha adheres to other materials at every point of contact' shall meet the performance requirements of the standard 'when tested as a composite with the other materials.' Thus, if the label, diagram and tag are affixed to the plastic shell of the restraint so that they adhere to the shell at every point of contact, they would be tested with the shell. If the label, diagram and tag do not adhere at every point of contact, section 4.2.1 requires them to meet the performance requirement of the standard when tested separately.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0884OpenMr. Tatsuo Kato, Engineering Representative, Nissan Motor Company, Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Tatsuo Kato Engineering Representative Nissan Motor Company Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Kato: This is in reply to your letter of September 27, 1972, on the subjec of the test procedures under Motor Vehicle Safety Standard No. 210, Seat Belt Anchorages.; Your question is whether the seat belt installed in the vehicle must b used for the anchorage test. The answer is no. The standard sets requirements only for anchorages, and the seat belts are merely means by which specified forces are applied to test the anchorages.; Truly yours, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1796OpenMr. Paul Utans, 55 Concord Street, Englewood, New Jersey 07631; Mr. Paul Utans 55 Concord Street Englewood New Jersey 07631; Dear Mr. Utans: This responds to your January 19, 1975 question whether S5.4.3 o Standard No. 105-75, *Hydraulic brake systems*, permits a brake fluid warning statement on a filler cap to be partially obscured by a locking component placed over it, and whether the statement in association with the recommended type of brake fluid.; The answer to both of your questions is no. Section S5.4.3(b) require that the statement be 'located so as to be visible by direct view'. This requirement prohibits an arrangement which would obscure any part of the statement, as would the design described in the drawings which accompany your letter. Section S5.4.3(b) permits a location within 4 inches of the brake fluid reservoir filler plug or cap to accommodate arrangements which do not permit use of the filler cap as a location.; The content of the brake fluid warning statement required by S5.4.3 i specified in every respect other than designation of the recommended type of brake fluid. However, S5.4.3 does limit the permissible designation to 'the recommended type of brake fluid as specified in 49 CFR S571.116' and sets out an example of 'DOT 3'. These criteria do not permit the addition of an automobile manufacturer's name. Such a recommendation could, of course, appear separately in the vehicle's owner's manual.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2913OpenMr. Eugene D. Sambucetti, Wesco Truck & Trailer Sales, P.O. Box 626, 1960 E. Main Street, Woodland, CA 95695; Mr. Eugene D. Sambucetti Wesco Truck & Trailer Sales P.O. Box 626 1960 E. Main Street Woodland CA 95695; Dear Mr. Sambucetti: This responds to your October 30, 1978, request to know how th National Highway Traffic Safety Administration (NHTSA) expects a trailer manufacturer to provide the lateral stability necessary to remain within a 12-foot-wide lane while stopping from 60 mph in the absence of antilock installation. Your question follows from an interpretation of the recent Ninth Circuit ruling in which the agency stated its view that trailers are still required to stop from 60 mph within the 12-foot-wide lane, but without the capability of 'no lockup' performance.; In interpreting the court's ruling that 'no lockup' performance o trailers was invalid, the NHTSA recognized that the 12-foot-wide lane requirement would probably also be invalid if the requirement for 90 p.s.i. air pressure in the trailer control line during the stop remained effective. As you know, there is no stopping distance for trailers that would otherwise require a strong brake application and resulting loss of lateral stability. The agency therefore concluded that the 90 p.s.i. requirement was invalidated, stating in its October 19th interpretation,; >>>It does appear that the requirement for 90 p.s.i. air pressure i the trailer control line during the stop constitutes a portion of the 'no lockup' requirement and is therefore invalidated by the court.<<<; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3601OpenThe Honorable John Glenn, United States Senator, 200 North High Street, Suite 600, Columbus, OH 43215; The Honorable John Glenn United States Senator 200 North High Street Suite 600 Columbus OH 43215; Dear Senator Glenn: This responds to your July 1, 1982, letter enclosing correspondenc from your constituent Mr. Donald M. Robinson. Mr. Robinson would like to know whether Federal regulations prohibit him from purchasing a pickup cab and chassis without the body attached. The answer to his question is no.; The National Highway Traffic Safety Administration only requires tha all vehicles be manufactured in compliance with the applicable motor vehicle safety standards. We have no requirement, nor do we know of any other Federal regulation, that would prevent Mr. Robinson from purchasing just the cab and chassis of a vehicle that he desires. When he adds his own utility body to the cab and chassis, he would become the final-stage vehicle manufacturer and would be required to certify that the completed vehicle complies with all applicable Federal safety standards. I am enclosing copies of the regulations pertinent to such an operation.*; If I can be of further assistance to you or Mr. Robinson, pleas contact me.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2440OpenMr. Ray Hartman, Crown Coach Corp., 2428 East 12th Street, Los Angeles, CA 90021; Mr. Ray Hartman Crown Coach Corp. 2428 East 12th Street Los Angeles CA 90021; Dear Mr. Hartman: This is in response to your letter of October 7, 1976, in which you as several questions concerning Standard No. 217, *Bus Window Retention and Release*, and Standard No. 222, *School Bus Passenger Seating and Crash Protection*.; Your first question asks whether a California regulation requirin 20-inch minimum seat spacing in school buses would be preempted by the requirement for 20-inch maximum seat spacing in Standard No. 222.; The National Traffic and Motor Vehicle Safety Act (the Act) provides i Section 103(d) that any state or local law or regulation on an aspect of motor vehicle performance covered by a Federal standard must be identical to that Federal standard. Although the NHTSA requirement is phrased in terms of maximum spacing while the California standard concerns minimum spacing, the aspect of performance in question is seat spacing. Therefore, it is the NHTSA's opinion that a California standard on seat spacing regulates the same aspect of performance and to the degree it is not identical to the Federal standard it would be preempted.; Your second question asks whether the seating reference point, a specified in relation to the H' Point used in SAE Standard J826b, varies with the size of different individuals. The seating reference point, as defined by the NHTSA in Part 571.3 allows the manufacturer some discretion in selecting a point that approximates the position of the pivot center of the human torso and the thigh. While the NHTSA definition does refer to the SAE procedures for H' point location that includes the specific measurements you cite, the manufacturer retains discretion to vary this point slightly as long as he can show that the point selected continues to simulate the position of the pivot center of the human torso and the thigh of the passengers for whom the seat is designed.; Finally, you note in your letter that compliance with the seat spacin required in Standard No. 222 might entail relocation of the side emergency exit, because Standard No. 217 requires that [a] vertical transverse plane tangent to the rearmost point of a seat back shall pass through the forward edge of a side emergency door.' The seat spacing requirement arguably could occasion the realignment of the side emergency door, but this does not have to be the case. The manufacturer is free to adjust seat spacing to be properly aligned with the emergency exit. The NHTSA's intent in this requirement is to provide an emergency exit opening extending at least 2 feet rearward of a vertical transverse plane tangent to the rearmost point of a seat back. The agency would not prohibit the use of doors wider than 2 feet as long as a minimum 2-foot opening is provided rearward of the reference plane and the latch mechanism is operated by a device located within the required 2-foot opening.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5385Open"M. Guy Dorleans Valeo Vision 34, rue St-Andr 93012 Bobigny Cedex France"; "M. Guy Dorleans Valeo Vision 34 rue St-Andr 93012 Bobigny Cedex France"; Dear M. Dorleans: This responds to your FAX of April 20, 1994, to Mik Perel of this agency, asking for an interpretation of Standard No. 108. The drawing in your letter depicts a four-lamp headlamp arrangement in which the outermost lamps (lower beam) incorporate HB4 light sources, and the innermost lamps (upper beam), HB3 light sources. In operation, the outermost lamps alone provide the lower beam. However, when the upper beam switch is thrown, all lamps are energized. You ask for confirmation of your interpretation that 'outer unit must fulfill table 15a for Low Beam, an (sic) also that inner must fulfill with HB3 alone table 15a High Beam.' Paragraph S7.5 of Standard No. 108 specifies requirements for four-lamp replaceable bulb headlamp systems such as the one you describe. The photometrics that apply to such systems are set forth in paragraph S7.5(b): 'The photometrics as specified in subparagraphs (c) through (e) of this paragraph (depicted in Figure 26) . . . .' Because subparagraph (d) applies to a headlamp equipped with dual filament replaceable light sources and Types HB3 and HB4 are single filament sources, the applicable subparagraph is (e), and, more specifically, the four-headlamp specifications of (e)(3). This will confirm your understanding. Under S7.5(e)(3), the lower beam is to be produced by the outermost lamps and designed to conform to the lower beam requirements of Figure 15, the upper beam by the innermost lamps and designed to conform to the upper beam requirements of Figure 15. This is confirmed in Figure 26. However, the photometrics of Figure 15A will apply on and after September 1, 1994, (Paragraph S7.1). Simultaneous activation of both upper and lower beams is permitted by S5.5.8 of Standard No. 108 for headlighting systems designed to conform to Figure 15. Later this year, we will amend Standard No. 108 to substitute Figure 15A for Figure 15, effective September 1, 1994. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0187OpenMr. E. W. Bernitt, Vice President, Safety and Quality Assurance, American Motors Corporation, 14250 Plymouth Road, Detroit, MI 48232; Mr. E. W. Bernitt Vice President Safety and Quality Assurance American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Bernitt: We have received your submittal of consumer information in response t the requirements of 49 CFR Part 375. That regulation requires that manufacturers submit their information to the Administrator 30 days in advance of the time it is made available to prospective purchasers. Since we have not required that this advance submittal be in the same form as that given to prospective purchasers, the following comments are only advisory in nature. There are several respects, however, in which your information, if supplied in this form to prospective or actual purchasers, would not satisfy the requirements of the regulations.; >>>1. The Stopping Distance information is presented as a 'range o stopping distances,' both in numerical and graphical form. The regulations clearly require a single stopping distance figure to be provided for a given group, that can be met or exceeded by all vehicles in the group. We do not know, and consumers surely would not know, the significance of the lower figure given. Even if it were clear, the provision of such additional, non-required information in close proximity to the required data would cause confusion in attempting to compare figures between various makes--the main purpose of the information.; 2. The provision of four sets of data in respect to partial failure o the braking system, for 'fronts operative' and 'rears operative,' and for lightly-loaded and maximum-loaded vehicles, is not in accordance with the regulation requirement that information be provided for the 'most adverse combination' of weights and system failures. As stated in item 1, above, the inserting of this additional information, self-serving in every case since only the worst element should be included, would make comparisons difficult and be unfair to competing manufacturers who followed the regulations strictly.; 3. The form of the Stopping Distance information would fail to satisf the requirement that the information be presented 'in essentially the form illustrated in Figure 1' of 49 CFR S 375.101. In particular, we refer to the placing of two columns side by side instead of the single-axis graph depicted in that figure, and the inclusion of other verbiage between the required statements and warnings and the information itself. The reference to shorter stopping distances with wheel lock-up and without restricting pedal effort, between the required information and the graphs, is especially objectionable, since the safety advantages of avoiding wheel skid were a particular concern in developing this regulation. Although the regulations do not prohibit the provision of other than required information in a Consumer Information booklet, they do require that it be separated in such a manner that the required information, both textual and quantitative, is presented in 'essentially the form illustrated.'; 4. The Tire Reserve Load section of the regulations requires that 'th table that is provided for a specific vehicle shall contain only information that is applicable to that vehicle.' This requirement prohibits a large, all-purpose chart such as yours, with information for many vehicles included on it, at least as far as the information given to the actual purchaser of a vehicle is concerned. More generally, the information is not presented in 'essentially the form illustrated in Figure 1' of 49 CFR S 375.102.; 5. The large, all-inclusive bar graph on Acceleration and Passin Ability does not present the information in 'essentially the form illustrated in Figure 1' of 49 CFR S 375.106, as required.<<<; We will be glad to answer any questions that you may have with respec to the requirements of these or other motor vehicle safety regulations and standards.; Sincerely, Robert Brenner, Acting Director |
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.