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: aiam2311OpenMr. David E. Martin, Director, Automotive Safety Engineering, Environmental Activities Staff, General Motors Corporation, General Motors Technical Center, Warren , MI, 48090; Mr. David E. Martin Director Automotive Safety Engineering Environmental Activities Staff General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Martin: This is in reply to your letter of March 8, 1976, asking for a amendment of S4.1.1.21 of Motor Vehicle Safety Standard No. 108 to allow a plus tolerance of 7.5 percent on maximum wattage requirements for Type 1A and 2A headlamps.; I enclose a copy of an interpretation furnished the General Electri Company which states that such a tolerance is allowed. However, to clarify our intent we plan to amend Standard No. 108 in the near future in the manner that you suggest.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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ID: aiam3150OpenMr. T. Fujita, Manager, Automotive Lighting, Engineering Department, Stanley Electric Co., Ltd, 2-9-13, Nakameguro Meguro- ku, Tokyo 153, Japan; Mr. T. Fujita Manager Automotive Lighting Engineering Department Stanley Electric Co. Ltd 2-9-13 Nakameguro Meguro- ku Tokyo 153 Japan; Dear Mr. Fujita: This is in reply to your letter of October 17, 1979, asking for a interpretation for Paragraph S4.3.1.7 of Federal Motor Vehicle Safety Standard No. 108.; S4.3.1.7 says in effect that a front turn signal lamp and a low bea headlamp may be closer to each other than 4 inches 'if the sum of the candlepower values of the turn signal lamp measured at the test points within each group listed in Figure 1 is not less than two and one-half times the sum specified for each group for yellow turn signal lamps.'; You have asked whether a motorcycle turn signal lamp should 'satisf the values specified in S4.3.1.7 or half those values'. The answer, is, the values specified in S4.3.1.7. Half those values would be 'less than two and one-half times the sum specified ...' and impermissible under S4.3.1.7.; I hope that this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4695OpenMr. Takahiro Maeda Assistant to the Vice President Engineering Division Yamaha Motor Corporation, U.S.A. P.O. Box 6555 Cypress, CA 90630; Mr. Takahiro Maeda Assistant to the Vice President Engineering Division Yamaha Motor Corporation U.S.A. P.O. Box 6555 Cypress CA 90630; Dear Mr. Maeda: This is in reply to your letter of September 28, l990 requesting an interpretation of Motor Vehicle Safety Standard No. 108. Table IV of the standard establishes a minimum 'edge to edge separation distance' between turn signal lamps and tail or stop lamps installed on motorcycles. You have asked whether the edge in question is the outer edge of the lamp assembly itself, or the edge of the reflector in the lamp. The minimum edge to edge separation distance is measured from the edge of the illuminated surface of one lamp to another, that is to say, from the edge of the effective projected luminous area of one lens to the edge of the effective projected luminous area of the other. It is unclear from the drawing you enclosed of the 'tail/brake lamp' whether the edge of its effective projected luminous area of the lens is at the edge of the reflector, or at the edge of the lamp (as appears to be the case with the 'turn signal'). If the former, the distance is measured between the edge of the tail/stop lamp reflector to the edge of the turn signal lamp assembly as you have initially indicated. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam1497OpenMr. Kenji Shimizu, Mitsubishi Motors Corporation, 24300 Southfield Road, Southfield, MI 48075; Mr. Kenji Shimizu Mitsubishi Motors Corporation 24300 Southfield Road Southfield MI 48075; Dear Mr. Shimizu: This responds to your verbal request to Mr. Herlihy of this office fo a determination that a 3-point, continuous loop, Type II seat belt assembly would meet the requirements of S4.1.2.3.1(a) of Standard No. 208 if its emergency-locking retractor were mounted at the outboard floor anchorage instead of at the roof rail. The belt is routed from the fixed upper torso end, through a slip-fitting latch and pelvic section, to the retractor.; Assuming the belt assembly meets any other adjustment requirement o S4.1.2.3.1, it would conform to S7.1 of Standard No. 208 and S4.1(g) of Standard No. 209 with the emergency-locking retractor mounted at the outboard floor anchorage. The upper torso restraint would 'adjust by means of an emergency-locking retractor' within the meaning of S7.1 as long as the continuous loop permitted slack from the floor-mounted emergency-locking retractor to reach the upper torso portion of the assembly.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3500OpenMr. G. R. Dufresne, Assistant Vice President, Textile Services Division, United States Testing Company, Inc., 14415 Park Avenue, Hoboken, NJ 07030; Mr. G. R. Dufresne Assistant Vice President Textile Services Division United States Testing Company Inc. 14415 Park Avenue Hoboken NJ 07030; Dear Mr. Dufresne: This responds to your July 24, 1981, letter directed to our Office o Enforcement in which you ask whether it would be permissible to test for compliance with Standard No. 302, *Flammability of Interior Materials*, in a manner different than that prescribed in the standard. The standard states that a 14-inch long section of material shall be burned in a test oven until the flame reaches within 1 1/2 inches from the end of the material. You state that for some fabrics this requires a test that can extend to 10 minutes. In a test of this length, the test oven can cause the glass front of the oven to break. You suggest that the test be discontinued after five minutes, and the burn rate calculated.; The test requirements of the standard are provided to show how th agency will test for compliance. However, it is not compulsory that a manufacturer adhere to every facet of the test procedures if it can satisfy itself that its product will comply with the standard by testing in another manner. As you know, the standard requires only that the burn rate of a material not exceed four inches per minutes. A 14-inch long section of material that has not burned completely to its end in five minutes obviously would not exceed the 4-inch per minutes burn rate. Accordingly, we do not see any reason that you could not terminate the test five minutes after the starting point specified in paragraph S5.3(e) of the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1028OpenMrs. Gussie Peer, 149 Willow Avenue, Staten Island, NY 10305; Mrs. Gussie Peer 149 Willow Avenue Staten Island NY 10305; Dear Mrs. Peer: Your recent letter to the National Transportation Safety Boar concerning bus window glass has been referred to me for reply.; Safety glazing in buses is regulated by Federal Motor Vehicle Safet Standard No. 205. In general, the windows in the vicinity of passengers may be either laminated safety glass or tempered safety glass, or rigid plastics, if the windows are readily removable. Hence, the Federal standard does not prohibit manufacturers from using glazing materials that perform as you suggest.; In the past few years, manufacturers have expressed interest i providing passengers with protection from missiles thrown at buses. I expect to see an increase in the use of materials that conform with your suggestion.; I am enclosing a summary of the Federal Motor Vehicle Safety Standard for your information.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam3015OpenMr. H. Miyazawa, Director, Automotive Lighting, Engineering Department, Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. H. Miyazawa Director Automotive Lighting Engineering Department Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Miyazawa: This is in reply to your letter of April 28, 1979, asking two question with respect to certification of lighting equipment by use of the DOT symbol, as permitted by S4.7.2 of Federal Motor Vehicle Safety Standard No. 108.; Your first question is whether disassembled parts such as lenses screws, or bulbs must also be certified as conforming to all applicable Federal motor vehicle safety standards. The answer is no, only the completed lamp assembly must be so certified.; You have also asked 'in the case of lamp lens incorporated with refle reflector do we have to label the DOT label on this reflex reflector certifying it meets FMVSS?' The answer is yes. Although the lamp lens is not a required equipment item and not certified since it is only part of a lamp, the reflex reflector incorporated in it must be certified since the reflector is an item required by Standard No. 108.; I hope this answers your questions. Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1182OpenMr. Gorou Utsunomiya, Branch Manager, 23777 Greenfield Rd., Southfield, Michigan 48075; Mr. Gorou Utsunomiya Branch Manager 23777 Greenfield Rd. Southfield Michigan 48075; Dear Mr. Utsunomiya: This is in reply to your letter of June 11, 1973, regarding th application of section 114 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C S1403) to Motor Vehicle Safety Standard No. 107, 'Reflecting Surfaces'. You refer to language in a letter dated April 10, 1973, from this agency to Mr. Kazushi Sakashita of Toyo Kogyo., Ltd., in which we indicated that certification of replacement vehicle parts pursuant to section 114 is required only with respect to parts to which a safety standard specifically applies.; Standard No. 107 applies to motor vehicles--passenger cars multipurpose passenger vehicles, trucks, and busses (paragraph S2 of Standard No. 107)-- and not to items of motor vehicle equipment. Consequently the certification of conformity to the standard required by section 114 is accomplished by the label affixed to each vehicle in accordance with 49 CFR Part 567, 'Certification'. That label represents a certification of conformity to all standards, including Standard No. 107, applicable to the vehicle. There is no requirement that the individual components listed in S4 of the standard, i.e. the windshield wiper arms and blades, the inside windshield moldings, the horn ring and hub of the steering wheel assembly, and the inside rearview mirror frame and mounting bracket, be certified independently.; Your truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1478OpenJohn F. McCuen, Esq., Kelsey-Hayes Company, Romulus, MI; John F. McCuen Esq. Kelsey-Hayes Company Romulus MI; Dear Mr. McCuen: This will acknowledge receipt of Kelsey- Hayes' petition to ad 'after-stop' to the description of the temperature range in S6.1.8.1 of Standard No. 121 and S7.4.2.1.2 of Standard No. 105a.; The temperature range is in fact intended to describe the after-sto temperature of the brakes, and the language of the sections will be clarified in the future.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4380OpenL.M. Short, Chief, Enforcement Services Division, Department of California Highway Patrol, P.O. Box 898, Sacramento, CA 95804; L.M. Short Chief Enforcement Services Division Department of California Highway Patrol P.O. Box 898 Sacramento CA 95804; Dear Mr. Short: This responds to your letter to our office concerning our certificatio requirements for manufacturers of school buses. I apologize for the delay in responding to your inquiry.; According to your letter, California's school bus regulations requir vehicles considered as 'school buses' under state law to be certified as 'school buses' under Federal law. Vehicles considered as 'school buses' under state law include multipurpose passenger vehicles (MPV's) used to carry two or more handicapped pupils confined to wheelchairs. Consequently, under California's school bus regulations, an MPV cannot be used to carry handicapped students unless it is certified as meeting our school bus safety standards. Because manufacturers have informed you that NHTSA prohibits them from certifying an MPV as a school bus, you request that we remove this restriction by permitting the school bus certification for MPV's.; Your understanding is correct that our regulations prohibit MPV's to b certified as 'school buses.' Under the National Traffic and Motor Vehicle Safety Act and NHTSA regulations, manufacturers classify their new motor vehicles in accordance with the definitions we issued for our motor vehicle safety standards (49 CFR Part 571.3) and certify that their vehicles meet all Federal safety standards applicable to the vehicle type. Under the definitions of Part 571.3, the issue of seating capacity makes the school bus and MPV definitions mutually exclusive. The passenger seating capacity of an MPV must be 9 or less, while that of a school bus must be 10 or more. A manufacturer cannot certify a vehicle as a 'school bus' in compliance with Federal school bus safety standards unless the vehicle is of a size that puts it within the school bus category.; Adopting your suggestion that we permit some MPV's to be certified a school buses could not be accomplished without changing either our 'school bus' definition, our regulations for certifying vehicles, or the application of our school bus safety standards. As explained below, we must decline your implicit request to make these changes because of a statutory restriction and because we believe their adoption is not warranted by a safety need.; We are precluded from adopting the suggestion that we expand our schoo bus definition to include some MPV's because our school bus definition is governed by legislation enacted by Congress. In the Motor Vehicle and Schoolbus Safety Amendments of 1974, Congress added a 'school bus' definition to the National Traffic and Motor Vehicle Safety Act which is based on the design and intended use of a 'bus.' Congress directed that upgraded school bus safety requirements be applied to buses that carry more than 10 passengers and that are determined by NHTSA likely to be significantly used for the purpose of school transportation.; Your second implicit suggestion is that we change our certificatio regulations to permit manufacturers to certify a vehicle as both an 'MPV' and a 'school bus.' Such a change would not be practical. A manufacturer's certification of a vehicle is a declaration that the vehicle is manufactured to comply with all Federal motor vehicle safety standards applicable to that vehicle type. Since our performance requirements for MPV's are not identical to those for school buses, an MPV cannot be manufactured to meet the standards applicable to both vehicle types.; The third suggestion implicit in your letter is that a dua certification can be effectuated by extending the application of our school bus safety standards to some MPV's. We are not aware of any data suggesting a safety need for such a change. MPV's already have their own safety standards to ensure adequate levels of safety performance for those vehicles. Because of those standards, we do *not* prohibit the sale of MPV's to transport school children. Further, we do not believe the change you suggest is necessary to address the issue raised in your letter. Federal law does not prohibit manufacturers from voluntarily manufacturing MPV's to meet school bus standards on aspects of performance that do not conflict with MPV standards, such as emergency exits and joint strength. California may thus specify performance standards now applicable to school buses for MPV's used to transport handicapped children, provided that the MPV's can continue to comply with MPV standards. Of course, the vehicles would still be certified only as MPV's.; In your letter, you mentioned that you examined the definitions se forth in Highway Safety Program Standard No. 17, *Pupil Transportation Safety*, for 'Type I' and 'Type II' school vehicles. As you know, Standard No. 17 was issued under the Highway Safety Act as a standard for State highway safety programs. Since the 'standard' consists of our recommendations for the operation of school vehicles, the Type I and Type II school vehicle definitions found in Standard No. 17 are relevant for determining the operational recommendations applicable to different school vehicles. Those definitions do not, however, change the Vehicle Safety Act's definition of a school bus or the Act's requirements for a manufacturer to certify school buses to all applicable Federal motor vehicle safety standards.; I hope this information is helpful. Please contact my office if yo have further questions.; Sincerely, Erika Z. Jones, 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.