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: aiam0873OpenMr. Heinrich von Wimmersperg, Development Engineer, 15929 Grand River Avenue, Detroit 27, MI; Mr. Heinrich von Wimmersperg Development Engineer 15929 Grand River Avenue Detroit 27 MI; Dear Mr. von Wimmersperg: Thank you for your letter of October 2, 1972, concerning the For 'Tot-Guard' and your child restraint patents.; The consumer complaints that we have received on the Ford Tot-Guar have been complaints focussing on the fit of the device for minimum recommended size children. The comments relate both to the ease with which small children may climb out of the device and slide under it, as well as to the vision restriction problem for the small child.; The Tot-Guard has proven to perform well in 30 mph frontal impacts wit the three- year-old child dummy in our research programs, but can be improved in lateral protection capability and in performance with the 50-pound child dummy.; We have just completed a research program to develop new concepts i child restraints and will very shortly be making these designs available for any manufacturer who chooses to produce one of these advanced design restraints.; A copy of your letter will be placed in the public docket along wit plans for the restraints developed on our child restraint development contract.; We are interested in reviewing and placing in the public docket copie of your designs for the infant car bed, which you mention in hopes of stimulating the production of a crashworthy design for such a device.; We appreciate your letter and are looking forward to hearing from yo in the near future.; Sincerely, Douglas W. Toms, Administrator |
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ID: aiam4257OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Dept., Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of November 21, 1986, with reference t the distance between a front turn signal lamp and a lower beam headlamp.; In brief, SAE Standard J588e, incorporated by reference in Standard No 108 requires a minimum separation distance of 4 inches between the optical axis (filament center) of the front turn signal lamp to the inside diameter of the retaining ring of the lower beam headlamp. You have pointed out that a replaceable bulb headlamp does not have a retaining ring, and you have presented two possible substitutes as a measuring point. The first (your Item A) is the outer edge of the headlamp, and the second (your Item B) is the end of the effective area of the reflector. You believe that Item B is the more appropriate.; We concur with your interpretation. Of the two options, the distance t the edge of the effective area of the reflector is the one most similar to the inside diameter of the retaining ring of the lower beam headlamp. The basis for this interpretation is the assumption that the headlamp lens between the outer edge of the headlamp and the edge of the effective area of the reflector is not used for production of the lamp's beam, has no significant luminance, and therefore will not mask the turn signal.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam2622OpenMr. Jerry W. McNeil, Director of Engineering, American Trailers, Inc., Box 26568, Oklahoma City, Oklahoma 73126; Mr. Jerry W. McNeil Director of Engineering American Trailers Inc. Box 26568 Oklahoma City Oklahoma 73126; Dear Mr McNeil: This responds to your May 25, 1977, letter asking whether two sampl certification labels you submitted comply with the requirements of Part 567, *Certification*, and Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*.; The National HIghway Traffic Safety Administration (NHTSA) does no issue advance approvals of compliance with Federal safety standards or regulations. The agency will, however, give you an informal opinion as to whether your labels appear to comply with the requirements. The two labels you submitted do not follow the format required by Part 567 for certification labels. Therefore, they do not appear to comply with the requirements. Your method of stating tire and rim sizes differs from that required in Part 567 and Standard No. 120. For example, you state your tire and rim information as follows: '10-20-f-Tires-7.5 Rims at 75 PSI Cold Dual.' By the requirements of Part 567 and Standard No. 120 as they apply to certification labels, this information should read: '10.00-20(f) tires, 20x7.5 rims, at 75 psi cold dual.' Further, the statement after GAWR 'maximum with minimum size tire-rims shown below' should be deleted from the certification label. I am enclosing a copy of Part 567 and Standard No. 120 for your information.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1865OpenMr. A.F. Bleiweiss, P.Eng., Vice President, Dominion Auto, Accessories Limited, 420 Keele Street, Toronto 9, Canada; Mr. A.F. Bleiweiss P.Eng. Vice President Dominion Auto Accessories Limited 420 Keele Street Toronto 9 Canada; Dear Mr. Bleiweiss: This is in response to your letter of March 29, 1975, inquiring as t the permissibility of selling your 'Panamirror' in the United States as aftermarket equipment.; Motor Vehicle Safety Standard No. 111, *Rearview Mirrors*, Provide minimum performance requirements for rearview mirrors on passenger cars and multipurpose passenger vehicles. According to the standard, the inside rearview mirror must furnish the driver with a specified field of view to the rear of substantially unit magnification. Any vehicle manufactured for sale, sold, or introduced into interstate commerce must be equipped with an inside rearview mirror that meets the designated level of performance. It appears that the 'Panamirror' would not satisfy the requirements of the provision, because it is convex in structure and therefore would not provide a view of substantially unit magnification.; If the mirror were installed on a vehicle as aftermarket equipmen (after the vehicle's first purchase for purposes other than resale) in such a way as to render inoperative the inside rearview mirror, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (Pub. L. 89-563) as amended (Pub. L. 93-492) would apply where the installation was accomplished by a manufacturer, distributer, dealer, or motor vehicle repair business. The section prohibits the named parties from knowingly rendering inoperative a system installed in compliance with an applicable motor vehicle safety standard.; Yours truly, James C. Schultz, Chief Counsel |
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ID: aiam0840OpenMr. Richard Stevens, Cody Chevrolet, Inc. Barre-Montpelier Road, Montpelier, VT 05602; Mr. Richard Stevens Cody Chevrolet Inc. Barre-Montpelier Road Montpelier VT 05602; Dear Mr. Stevens: This is in reply to your letter of August 1, 1972, to the attention o Mr. Jerome Palisi of our White Plains, New York Office, concerning certification requirements for a vehicle which you describe and indicate will be used by a college to transport ball teams and school personnel, but will not be equipped with flashing lights or other special school bus equipment. You apparently wish to know whether you must consider this vehicle as a school bus for purposes of certification to Federal requirements.; 'School bus' is defined in the motor vehicle safety standards to mean bus 'designed primarily to carry children to and from school, but not including buses operated by common carriers in urban transportation of school children' (49 CFR 571.3). Based upon the description you provide, the NHTSA would not consider the vehicle you describe to be a school bus. For purposes of certification to Federal requirements (49 CFR Parts 567 and 568), there, 'gross vehicle weight rating' should not be computer under the minimum values specified for school buses. In addition, the requirement that vehicle type be inserted on the certification label should be met in inserting, 'BUS.'; This letter should not be construed to mean that the NHTSA takes position as to whether this vehicle need, under State law, conform to requirements for school buses. The State must determine the scope and application of its own laws.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3581OpenMr. Ron Gustafson, Furudals Buruks Kursinternat, 790 70 FURUDUAL Sweden; Mr. Ron Gustafson Furudals Buruks Kursinternat 790 70 FURUDUAL Sweden; Dear Mr. Gustafson: This responds to your letter of June 28, 1982, asking abou requirements applicable to child restraints sold in the United States as well as any necessary permits or licenses. You also asked about any U.S. testing organizations, procedures or standards for child restraints.; All child restraints sold in the U.S. must conform with the minimu performance requirements of Federal Motor Vehicle Safety Standard No. 213, *Child Restraint Systems*. The standard also sets out the test procedures that are used to measure the performance of child restraints. There are no other performance requirements or test procedures applicable to child restraints. I am enclosing a copy of the standard.; You are not required to obtain a permit or license from this agenc prior to selling a child restraint in the U.S., nor are you required to obtain approval from any U.S. testing organization. As a manufacturer of motor vehicle equipment, you are required by Part 566, *Manufacturer Identification*, of our regulation to submit certain identifying information to the agency. I have enclosed a copy of Part 566.; In addition,m you would be required by the National Traffic and Moto Vehicle Safety Act (15 U.S.C. S1392 *et seq.*) to certify that your child restraint complies with all applicable Federal Motor Vehicle Safety Standards. Under the Act, you would also be responsible for conducting a notification and remedy campaign for any safety-related defect in your product. I am enclosing a copy of the Act, which defines your responsibilities as a manufacturer.; If you have any further question, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3974OpenThe Honorable John S. McCain, III, U.S. House of Representatives, Washington, DC 20515; The Honorable John S. McCain III U.S. House of Representatives Washington DC 20515; Dear Mr McCain: Thank you for bringing to our attention the problems experienced b your constituents due to conflicting State laws on motor vehicle window tinting.; The National Highway Traffic Administration (NHTSA) has issued Federal motor vehicle safety standard governing window tinting in new vehicles and replacement equipment, and Federal law also limits the extent to which certain commercial businesses may apply additional tinting. However, Federal law does not preclude individuals from tinting their vehicle windows. That matter is left to the States, and we understand the difficulties that may arise when the tinting laws of adjacent States are inconsistent.; Our agency has been discussing the issue of window tinting with th American Association of Motor Vehicle Administrators, in an effort to better explain the interaction of Federal and State laws in this area. That may also be an appropriate forum in which to consider ways to resolve conflicts between differing State tinting laws. While NHTSA and each state government has a valid interest in preserving its legal authority, we all share a common interest in promoting highway safety and in minimizing inconvenience to traveling motorists. In our view, a well-coordinated and cooperative approach among the various parties can help to address apparent problems in this area.; We will keep you advised of our progress in those discussions. appreciate knowing of your concern in this matter, and I hope you will feel free to contact me if this agency can be of further assistance.; Sincerely, Diane K. Steed |
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ID: aiam1801OpenMr. Fred W. Cords, Minnesota Automotive, Inc., Box 2074, North Mankato, MN 56001; Mr. Fred W. Cords Minnesota Automotive Inc. Box 2074 North Mankato MN 56001; Dear Mr. Cords: This is in reply to your letter of January 6, 1975, requesting a opinion on whether a person who installs a Mico Brake Lock device on a new vehicle before its sale to the first purchaser is required to affix an alterer label in accordance with 49 CFR SS 567.7 and 568.8. You state that you believe the device, which serves as a hydraulic parking brake, is readily attachable because it can be installed in a minimum amount of time and does not in any way alter the operation of the vehicle's original brake system.; The NHTSA will generally abide by a good faith determination on th part of a manufacturer that a device is readily attachable. Such a decision should be based primarily on the intricacy of the installation of the device. Simple tools, a relatively short installation time, and the ability to install the device without extensively modifying the vehicle would all be factors pointing to a decision that a component is readily attachable. You should note that section 567.7 of the Certification regulations also requires an alterer label when the installation of a component invalidates a vehicle's existing weight ratings, whether or not the component is readily attachable. On the basis of your letter, however, it appears to us that this would not occur as a result of installation of the Mico Brake Lock device.; If your device meets these criteria, no additional labeling will b required.; Yours truly, James C. Schultz, Acting Chief Counsel |
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ID: aiam3580OpenMr. Ron Gustafson, Furudals Buruks Kursinternat, 790 70 FURUDUAL Sweden; Mr. Ron Gustafson Furudals Buruks Kursinternat 790 70 FURUDUAL Sweden; Dear Mr. Gustafson: This responds to your letter of June 28, 1982, asking abou requirements applicable to child restraints sold in the United States as well as any necessary permits or licenses. You also asked about any U.S. testing organizations, procedures or standards for child restraints.; All child restraints sold in the U.S. must conform with the minimu performance requirements of Federal Motor Vehicle Safety Standard No. 213, *Child Restraint Systems*. The standard also sets out the test procedures that are used to measure the performance of child restraints. There are no other performance requirements or test procedures applicable to child restraints. I am enclosing a copy of the standard.; You are not required to obtain a permit or license from this agenc prior to selling a child restraint in the U.S., nor are you required to obtain approval from any U.S. testing organization. As a manufacturer of motor vehicle equipment, you are required by Part 566, *Manufacturer Identification*, of our regulation to submit certain identifying information to the agency. I have enclosed a copy of Part 566.; In addition,m you would be required by the National Traffic and Moto Vehicle Safety Act (15 U.S.C. S1392 *et seq.*) to certify that your child restraint complies with all applicable Federal Motor Vehicle Safety Standards. Under the Act, you would also be responsible for conducting a notification and remedy campaign for any safety-related defect in your product. I am enclosing a copy of the Act, which defines your responsibilities as a manufacturer.; If you have any further question, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4443OpenMr. Toshio Maeda Executive Vice President & Chief Operating Officer Nissan Research & Development, Inc. P.O. Box 8650 Ann Arbor, Michigan 48104; Mr. Toshio Maeda Executive Vice President & Chief Operating Officer Nissan Research & Development Inc. P.O. Box 8650 Ann Arbor Michigan 48104; Dear Mr. Maeda: This is in reply to your letter of June 30, 1987 asking for an interpretation of paragraph S4.1.1.36(b)(3) of Motor Vehicle Safety Standard No. 108. That paragraph specifies in pertinent part that a replaceable bulb headlamp shall be designed to conform to Section 6.1-Aiming Adjustment Test, of SAE Standard J580 AUG79 Sealed Beam Headlamp Assembly. Section 6.1.1 states that 'when the headlamp assembly is tested in the laboratory, a minimum aiming adjustment of +/-4 deg. shall be provided in both the vertical and horizontal planes.' You have asked whether the aiming adjustment is to be achieved by the headlamp assembly, or by both the headlamp assembly 'and by the headlamp when it is mounted on the vehicle.' SAE J580 applies to the design of headlamp assemblies, including the functional parts other than the headlamps, such as aiming and mounting mechanisms and hardware. The assembly may include one or more headlamps. Although the headlamp assembly is tested in the laboratory, its design must be identical to the headlamp assembly used on the vehicle. Thus, if the aiming adjustment requirement is met by the headlamp assembly in the laboratory, it should also be met when the assembly is installed on the vehicle. An individual headlamp installed on the vehicle need not meet the aiming adjustment test unless that headlamp is part of a headlamp assembly comprising only one headlamp. I hope that this answers your question. 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.