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: aiam0715OpenMs. Hope C. Kocher, Secretary, International Houseing Incorporated, 32 West Penn Avenue, Cleona, PA 17042; Ms. Hope C. Kocher Secretary International Houseing Incorporated 32 West Penn Avenue Cleona PA 17042; Dear Ms. Kocher: This is to acknowledge your letter of May 19, 1972, regarding tir identification and recordkeeping.; Regulation Part 574 requires a vehicle manufacturer to maintain record of tires on each vehicle shipped to a dealer and requires that he maintain a record of the name and address of the first purchaser of the vehicle for a period of three years. The purpose, of course, is to enable him to locate tires in the event of a recall. The name and address of the purchaser is provided by the dealer. The manufacturer is not required by the regulation to record each identification number for each tire, but may do so by group or category. There is a strong possibility that all tires on one vehicle will be of the same brand and will have the same identification number. The manner in which a manufacturer chooses to maintain the tire records is optional and the dealer would be expected to cooperate in his system of recording data. It is primarily a matter of agreement between manufacturer and dealer.; In the event the original tires on a vehicle are changed by the deale prior to sale, he must report the new tire identification numbers and the purchaser's name and address to the manufacturer of the tires sold with the vehicle.; We note that your letter refers to registration of *serial* numbe rather than *identification* number. It is the latter that is subject to the regulation.; We trust this information answers your questions. Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam5537OpenMr. Valter Sforca 84 Thomas Street Newark, NJ 07114; Mr. Valter Sforca 84 Thomas Street Newark NJ 07114; Dear Mr. Sforca: This is in reply to your letter of April 20, 1995 asking if there is a regulation that applies to the importation of an 'air equalizer for tire pressure.' Although you have not described your device, there are no Federal motor vehicle safety standards that apply to equipment installed in motor vehicles that regulate the air pressure of tires. If you are asked by the U.S. Customs Service to execute an HS-7 Declaration Form at the port of entry, you may check Box 1, declaring that the equipment was manufactured on a date when no applicable Federal motor vehicle safety standard was in effect. Because this device is motor vehicle equipment, and because you apparently would be its importer, you would be responsible for notifying buyers and recalling it if either you or we decided that it contained a safety related defect. We don't understand your phrase 'the system have a safety valve for the air brakes the truck, for a properly stop'. However, if the 'air equalizer' is installed by a manufacturer, distributor, dealer, or motor vehicle repair business, that person must not knowingly make inoperative any part of a truck's air brake system by installing the air equalizer. I am enclosing a copy of a letter concerning what appears to be a similar device, which will explain this more fully. If you have any further questions, you may refer them to Taylor Vinson of this Office, with whom you spoke previously (202-366-5263). Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam5538OpenMr. Valter Sforca 84 Thomas Street Newark, NJ 07114; Mr. Valter Sforca 84 Thomas Street Newark NJ 07114; Dear Mr. Sforca: This is in reply to your letter of April 20, 1995 asking if there is a regulation that applies to the importation of an 'air equalizer for tire pressure.' Although you have not described your device, there are no Federal motor vehicle safety standards that apply to equipment installed in motor vehicles that regulate the air pressure of tires. If you are asked by the U.S. Customs Service to execute an HS-7 Declaration Form at the port of entry, you may check Box 1, declaring that the equipment was manufactured on a date when no applicable Federal motor vehicle safety standard was in effect. Because this device is motor vehicle equipment, and because you apparently would be its importer, you would be responsible for notifying buyers and recalling it if either you or we decided that it contained a safety related defect. We don't understand your phrase 'the system have a safety valve for the air brakes the truck, for a properly stop'. However, if the 'air equalizer' is installed by a manufacturer, distributor, dealer, or motor vehicle repair business, that person must not knowingly make inoperative any part of a truck's air brake system by installing the air equalizer. I am enclosing a copy of a letter concerning what appears to be a similar device, which will explain this more fully. If you have any further questions, you may refer them to Taylor Vinson of this Office, with whom you spoke previously (202-366-5263). Sincerely, John Womack Acting Chief Counsel Enclosure; |
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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: aiam5535OpenMr. Valter Sforca 84 Thomas Street Newark, NJ 07114; Mr. Valter Sforca 84 Thomas Street Newark NJ 07114; Dear Mr. Sforca: This is in reply to your letter of April 20, 1995 asking if there is a regulation that applies to the importation of an 'air equalizer for tire pressure.' Although you have not described your device, there are no Federal motor vehicle safety standards that apply to equipment installed in motor vehicles that regulate the air pressure of tires. If you are asked by the U.S. Customs Service to execute an HS-7 Declaration Form at the port of entry, you may check Box 1, declaring that the equipment was manufactured on a date when no applicable Federal motor vehicle safety standard was in effect. Because this device is motor vehicle equipment, and because you apparently would be its importer, you would be responsible for notifying buyers and recalling it if either you or we decided that it contained a safety related defect. We don't understand your phrase 'the system have a safety valve for the air brakes the truck, for a properly stop'. However, if the 'air equalizer' is installed by a manufacturer, distributor, dealer, or motor vehicle repair business, that person must not knowingly make inoperative any part of a truck's air brake system by installing the air equalizer. I am enclosing a copy of a letter concerning what appears to be a similar device, which will explain this more fully. If you have any further questions, you may refer them to Taylor Vinson of this Office, with whom you spoke previously (202-366-5263). Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam5536OpenMr. Valter Sforca 84 Thomas Street Newark, NJ 07114; Mr. Valter Sforca 84 Thomas Street Newark NJ 07114; Dear Mr. Sforca: This is in reply to your letter of April 20, 1995 asking if there is a regulation that applies to the importation of an 'air equalizer for tire pressure.' Although you have not described your device, there are no Federal motor vehicle safety standards that apply to equipment installed in motor vehicles that regulate the air pressure of tires. If you are asked by the U.S. Customs Service to execute an HS-7 Declaration Form at the port of entry, you may check Box 1, declaring that the equipment was manufactured on a date when no applicable Federal motor vehicle safety standard was in effect. Because this device is motor vehicle equipment, and because you apparently would be its importer, you would be responsible for notifying buyers and recalling it if either you or we decided that it contained a safety related defect. We don't understand your phrase 'the system have a safety valve for the air brakes the truck, for a properly stop'. However, if the 'air equalizer' is installed by a manufacturer, distributor, dealer, or motor vehicle repair business, that person must not knowingly make inoperative any part of a truck's air brake system by installing the air equalizer. I am enclosing a copy of a letter concerning what appears to be a similar device, which will explain this more fully. If you have any further questions, you may refer them to Taylor Vinson of this Office, with whom you spoke previously (202-366-5263). Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam2671OpenMr. Ray Sizemore, Crane Carrier Company, 1925 N. Sheridan, P.O. Box 51191, Tulsa, OK 74151; Mr. Ray Sizemore Crane Carrier Company 1925 N. Sheridan P.O. Box 51191 Tulsa OK 74151; Dear Mr. Sizemore: This responds to Crane Carrier Corporation's June 8, 1977, questio whether the maximum time limits specified by S5.1.1 of Standard No. 121, *Air Brake Systems*, for build-up of brake system air pressure from 85 to 100 psi includes the time taken to build up air pressure in an accessory reservoir (for an air starter) that is replenished only when the truck is started.; The answer to your question is no. Section S5.1.1 is a performanc requirement that assures that repeated use of the brakes during vehicle operation will not deplete the available air supply because of insufficient air compressor capacity. The purpose of this requirement only indirectly relates to the initial air pressure build-up that occurs when the vehicle is first started.; The agency's existing laboratory procedure for compliance testin provides for fully charging the air brake system (and any accessory reservoirs which charge automatically in the process) before the test is begun. The engine is shut off while brake system air pressure is reduced to a level that permits a subsequent build-up for measurement purposes. In order to properly test vehicles with air starters, the agency is modifying its procedure to keep the engine running throughout the test, so that the air starter reservoir remains fully charged throughout the measurement period.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5424OpenMs. Denise Davis 3177 Lotheridge Rd. Gainesville, GA 30501; Ms. Denise Davis 3177 Lotheridge Rd. Gainesville GA 30501; Dear Ms. Davis: This responds to your letter asking for help in matter involving window tinting on your car. I apologize for the delay in responding. You explain in your letter that you asked a window tinting store for a sticker showing that the tint on your windows met Georgia law. The store informed you that it cannot issue you a sticker because your windows only allow 20 percent sunlight through, and the new law requires 35 percent. To get a sticker, you would have to remove the tint, which you explain will be costly. You also state that your windows were tinted seven years ago when you purchased your car, and at the time you had your windows tinted, you were 'not breaking any law.' I regret that we cannot help you pay to have the tint removed. The primary purpose of this agency is to regulate the manufacture and sale of new motor vehicles and new motor vehicle equipment. We have no authority to provide funds to citizens to help them correct problems with their vehicles or equipment. Please bear in mind that the '35 percent' law was adopted by Georgia to regulate the operation of vehicles. Thus, we suggest that you contact the Georgia Department of Motor Vehicles for information about this matter. We appreciate your efforts to reduce the tint on your vehicle and are sorry that we are unable to assist you. If you have any other questions, please contact Mr. Marvin Shaw of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam5284OpenSgt. Dennis Platt, Supervisor Vehicle Safety & Equipment Section State of Utah Department of Public Safety Utah Highway Patrol 4501 South 2700 West Salt Lake City, UT 84119-5994; Sgt. Dennis Platt Supervisor Vehicle Safety & Equipment Section State of Utah Department of Public Safety Utah Highway Patrol 4501 South 2700 West Salt Lake City UT 84119-5994; Dear Sgt. Platt: This responds to your letter of December 7, 1993 requesting confirmation of a statement made by a NHTSA officer that there is no federal regulation that requires replacement of a deployed air bag. I am enclosing two letters that explain legal obligations to replace air bags which have been deployed. The first letter, dated January, 19, 1990, is to Ms. Linda L. Conrad. The second letter, dated March 4, 1993, is to Mr. Robert A. Ernst. As explained in those letters, Federal law does not require replacement of a deployed air bag in a used vehicle. In addition, there is no Federal law that prohibits selling a used vehicle with a supplemental restraint that is inoperable because of a previous deployment. However, our agency strongly encourages dealers and repair businesses to replace deployed air bags whenever vehicles are repaired or resold, to ensure that the vehicles will continue to provide maximum crash protection for occupants. Moreover, a dealer or repair business may be required by state law to replace a deployed air bag, or be liable for failure to do so. I am also enclosing a copy of the information sheet referred to in the two letters discussed above. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures; |
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ID: aiam1252OpenMr. Ray Hartman, Vice President, Engineering, Crown Coach Corporation, 2500 East Twelfth Street, Los Angeles, CA 90021; Mr. Ray Hartman Vice President Engineering Crown Coach Corporation 2500 East Twelfth Street Los Angeles CA 90021; Dear Mr. Hartman: This is in reply to your letter of August 28, 1973, concerning th effective date of Motor Vehicle Safety Standard No. 121. Your direct question is whether the effective date is the starting or completion date for the vehicle's components or the starting date for the vehicle.; Standard No. 121 applies to the vehicle and its effective dat therefore relates to the vehicle, rather than to any of its components. A vehicle completed after the effective date will have to meet the standard, even though it is equipped with a foundation brake system that was manufactured before the effective date.; The vehicle's completion date, rather than its starting date, is th date that determines whether it must conform to the standard. If your company manufactures its vehicles from the ground up, rather than installing a body on a vehicle built by another manufacturer, the relevant completion date is the date you complete your manufacturing operation. However, if you buy an incomplete vehicle, as defined in our regulation on vehicles manufactured in two or more stages (49 CFR Part 568), and complete that vehicle, you may choose as the completion date for purposes of Standard No. 121 the date on which the manufacturer of the incomplete vehicle finished his work, the date on which you completed the vehicle or any date in between.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.