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: aiam3709OpenMr. C. J. Johnson, Manager, Product Reliability, The BF Goodrich Company, Tire Group, 500 South Main Street, Akron, OH 44318; Mr. C. J. Johnson Manager Product Reliability The BF Goodrich Company Tire Group 500 South Main Street Akron OH 44318; Dear Mr. Johnson: This is in response to your May 12, 1983 letter regarding the tir sidewall molding requirements of the Uniform Tire Quality Grading Standards. In that letter you indicated that, acting in reliance on statements by a NHTSA employee, your company modified certain new tire molds by deleting the numerical treadwear grade from the sidewall label, but leaving the word 'TREADWEAR' in place. NHTSA subsequently stated, in a letter to Toyo Tire Company, that if the sidewall molded label is modified, both the numerical grade and the word 'TREADWEAR' should be deleted. You also indicated that BF Goodrich is now in the process of modifying the molds again to delete the word 'TREADWEAR'.; In light of your good faith reliance on agency statements and you current efforts to conform to the policy stated in our letter to Toyo Tire Company, NHTSA will take no enforcement action regarding sidewall molding requirements for tires produced through the completion of the mold modification process.; For future reference, please be aware formal interpretations of lega requirements are issued only by this office and only in writing. To obtain an interpretation upon which reliance can be placed for purposes of making business decisions, you should direct a letter of inquiry to the Chief Counsel's Office.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2509OpenMr. Steven Katz, Silver Thread Studios, 413 A Sixth Avenue, Brooklyn, NY 11215; Mr. Steven Katz Silver Thread Studios 413 A Sixth Avenue Brooklyn NY 11215; Dear Mr. Katz: This responds to your February 1, 1977, letter requesting informatio concerning the Federal regulations that would be applicable to glazing for use in van-type vehicles. Your assumption that the glazing regulation is not applicable to plastic material used for porthole windows and sun-roofs in vans is incorrect.; Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials*, 4 CFR 571.205, specifies requirements for all glazing materials for use in motor vehicles and motor vehicle equipment. The standard specifies the types of glazing that may be used in various locations in vehicles and, in addition, specifies performance requirements for each type of glazing. Although the standard does permit the use of plastic glazing in side windows and sun-roofs of van-type vehicles, the plastic glazing must meet specified performance requirements.; I am enclosing a copy of Standard No. 205 (and the ANS Z26 standar that is incorporated by reference in Standard No. 205) for your information. From the standard you will be able to determine the various types of glazing that may be used for side windows and sun-roofs in vans.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2856OpenMr. Alfred Massarone, Chief, Motor Vehicle Safety and Emission Control Division, Department of Transportation, State Office Building, Providence, RI 02903; Mr. Alfred Massarone Chief Motor Vehicle Safety and Emission Control Division Department of Transportation State Office Building Providence RI 02903; Dear Mr. Massarone: I regret the delay in answering your letter. This responds to you questions concerning the recent amendment of Safety Standard No. 205, *Glazing Materials*, that permits the use of rigid plastics in the side windows of buses. Specifically, you ask whether the amendment includes school buses and whether plastic glazing would be allowed in entrance doors and in rear emergency doors of school buses.; Safety Standard No. 205 was amended to permit the use of rigid plasti glazing in all doors and windows of buses, except windshields or in windows to the immediate right or left of the driver (42 FR 61465, December 5, 1977). This amendment is applicable to school buses, since they are a special sub-category of bus.' The plastic glazing would not be allowed in a bus entrance door since this would constitute a window to the immediate right' of the driver. Plastic glazing would be allowed in the rear emergency door, however, since that location was not excepted in the amendment.; Please contact Hugh Oates of this office if you have any furthe questions (202-426-2992).; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2247OpenMr. George A. Hunt, Engineering Manager, Motor Coach Industries, Inc., Pembina, ND 58271; Mr. George A. Hunt Engineering Manager Motor Coach Industries Inc. Pembina ND 58271; Dear Mr. Hunt: This responds to Motor Coach Industries' February 20, 1976, lette asking whether Standard No. 121, *Air Brake Systems*, requires the installation of parking brakes on all non-steerable axles of a bus, including a lightly-loaded axle, in satisfaction of the emergency braking provisions of S5.7.1. Once parking brakes are applied on the non-driving, lightly-loaded axle on some Motor Coach Industries (MCI) buses in cold, wet weather, the linings can freeze to the drums and 'lock' the wheels so that they will not turn even after the parking brake is released. You suggest that parking brakes are inappropriate on a lightly-loaded axle, citing an interpretation of the standard that stated parking brakes are not required on an air-lift axle which lifts off the ground when the vehicle is parked.; MCI raised the same question of parking brake requirements fo lightly-loaded axles in an April 17, 1972, letter requesting interpretation of the provision of S5.7.1 that requires automatic application of parking brakes. At the time, the NHTSA had just issued S5.7.1, expanding the methods for meeting performance levels for emergency braking performance. The question of whether parking brakes should be required on all axles under S5.7.1 was left open pending formal rulemaking.; What was not raised in MCI's April 1972 letter was whether both method for meeting S5.7.1 performance levels necessitate parking brakes on all non-steerable axles. Section S5.7.1.2 permits reliance on retardation force capabilities of each non-steerable axle or, in the alternative, reliance on vehicle stopping capability using the vehicle's available parking brakes. In the second case, the NHTSA does not interpret S5.7.1 to require installation of parking brakes on an axle if it is not necessary to meet the stopping performance of S5.7.2.3 specified under S5.7.1.2. To the degree the language of S5.7.1 does not specifically address this method of satisfying the requirement, we regret that the agency's July 1972 response was not more clear.; An interpretative amendment of S5.7.1 would be appropriate in view o the difficulties that its misinterpretation has caused. However, in view of the short time remaining before the automatic application option will no longer be available, the NHTSA does not expect to undertake rulemaking to formalize this interpretation.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam1870OpenMr. David A. Tenquist, Marketing Department, Novus, Inc., 5301 B Edina Industrial Blvd., Minneapolis, MN 55435; Mr. David A. Tenquist Marketing Department Novus Inc. 5301 B Edina Industrial Blvd. Minneapolis MN 55435; Dear Mr. Tenquist: This is in reply to your letter of March 12, 1975, inquiring as t whether any safety regulation of the National Highway Traffic Safety Administration applies to the 'Novus Windshield Repair Kit,' manufactured by your firm.; An advertising brochure for the product states that the material use in the process 'is a special waterproof epoxy that not only fills the fissure in the glass but also bonds the crack surfaces to prevent formation or extension of radial cracks.'; There is no safety regulation of the National Highway Traffic Safet Administration, nor any other Federal law or regulation, which prohibits the use of such a material or process in the repair of windshields which have previously been installed in vehicles and damaged in use. Using such a material or process in a new windshield which may require repair as the result of damage sustained in shipment could cause the windshield to fail to meet the performance requirement of Motor Vehicle Safety Standard No. 205 (49 CFR S 571.205) and we would therefore discourage use of the Novus kit on new windshields.; Please do not hesitate to contact us if we may be of furthe assistance.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1869OpenMr. David A. Tenquist, Marketing Department, Novus, Inc., 5301 B Edina Industrial Blvd., Minneapolis, MN 55435; Mr. David A. Tenquist Marketing Department Novus Inc. 5301 B Edina Industrial Blvd. Minneapolis MN 55435; Dear Mr. Tenquist: This is in reply to your letter of March 12, 1975, inquiring as t whether any safety regulation of the National Highway Traffic Safety Administration applies to the Novus Windshield Repair Kit,' manufactured by your firm.; An advertising brochure for the product states that the material use in the process is a special waterproof epoxy that not only fills the fissure in the glass but also bonds the crack surfaces to prevent formation or extension of radial cracks.'; There is no safety regulation of the National Highway Traffic Safet Administration, nor any other Federal law or regulation, which prohibits the use of such a material or process in the repair of windshields which have previously been installed in vehicles and damaged in use. Using such a material or process in a new windshield which may require repair as the result of damage sustained in shipment could cause the windshield to fail to meet the performance requirement of Motor Vehicle Safety Standard No. 205 (49 CFR S 571.205) and we would therefore discourage use of the Novus kit on new windshields.; Please do not hesitate to contact us if we may be of furthe assistance.; Yours truly. Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3296OpenMr. Martin D. Davis, Meon, Inc., 221-18 Merrick Boulevard, Springfield Gardens, NY 11413; Mr. Martin D. Davis Meon Inc. 221-18 Merrick Boulevard Springfield Gardens NY 11413; Dear Mr. Davis: This is in response to your letter of May 12, 1980, requestin interpretation of paragraph (c)(2)(iii) of the Uniform Tire Quality Grading Standards (49 CFR S 575.104). That paragraph provides that to qualify as a limited production tire a tire cannot have been listed as a vehicle manufacturer's recommended tire size designation for a new motor vehicle produced in or imported into the United States in quantities greater than 10,000 during the preceding calendar year. You ask whether a tire meets this requirement if its size is recommended for use on several new vehicles, none of which is produced in quantities greater than 10,000 yearly, but which in the aggregate account for annual production in excess of 10,000 vehicles.; Paragraph (c)(2)(iii) refers to '*a* vehicle manufacturer's recommende tire size designation (emphasis added)' and '*a* new motor vehicle (emphasis added)', indicating that the 10,000 vehicle limitation refers to the production or importation of a particular vehicle model, rather than the total of all models for which the tire size is recommended. Thus, if a tire's size is recommended for use on several vehicle models, none of which is produced in or imported into the United States in quantities greater 10,000 during the calendar year preceding the year of the tire's manufacture, the tire would meet the criterion of paragraph (c)(2)(iii).; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3295OpenMr. Martin D. Davis, Meon, Inc., 221-18 Merrick Boulevard, Springfield Gardens, NY 11413; Mr. Martin D. Davis Meon Inc. 221-18 Merrick Boulevard Springfield Gardens NY 11413; Dear Mr. Davis: This is in response to your letter of May 12, 1980, requestin interpretation of paragraph (c)(2)(iii) of the Uniform Tire Quality Grading Standards (49 CFR S 575.104). That paragraph provides that to qualify as a limited production tire a tire cannot have been listed as a vehicle manufacturer's recommended tire size designation for a new motor vehicle produced in or imported into the United States in quantities greater than 10,000 during the preceding calendar year. You ask whether a tire meets this requirement if its size is recommended for use on several new vehicles, none of which is produced in quantities greater than 10,000 yearly, but which in the aggregate account for annual production in excess of 10,000 vehicles.; Paragraph (c)(2)(iii) refers to '*a* vehicle manufacturer's recommende tire size designation (emphasis added)' and '*a* new motor vehicle (emphasis added)', indicating that the 10,000 vehicle limitation refers to the production or importation of a particular vehicle model, rather than the total of all models for which the tire size is recommended. Thus, if a tire's size is recommended for use on several vehicle models, none of which is produced in or imported into the United States in quantities greater 10,000 during the calendar year preceding the year of the tire's manufacture, the tire would meet the criterion of paragraph (c)(2)(iii).; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1563OpenMr. Jack R. Gilstrap, General Manager, Southern California Rapid Transit District, 1060 South Broadway, Los Angeles, CA, 90015; Mr. Jack R. Gilstrap General Manager Southern California Rapid Transit District 1060 South Broadway Los Angeles CA 90015; Dear Mr. Gilstrap: This is in reply to your letter of July 17, 1974, asking whether S4. of Standard No. 108 prohibits a bus manufacturer from installing wiring that could later be connected by the purchaser to normally steady-burning clearance lamps, enabling them to be flashed to signal a crime in progress. The vehicle modifications here concerned are the installation both of certain wiring by General Motors and dual filament bulbs in each clearance lamp by the Southern California Rapid Transit District.; Paragraph S4.6 requires that signalling lamps specified in Standard No 108 shall flash when activated, and that 'all other lamps' shall be steady-burning. Paragraph S4.1.3 in part prohibits the installation of motor vehicle equipment that impairs the effectiveness of the lighting equipment required by Standard No. 108.; We construe the phrase 'all other lamps' in S4.6(b) to mean lamps tha are required by Standard No. 108. Supplemental lamps on ambulances and police cars, for example, that flash in normal use are not included in the standard. Similarly, it would appear that when the clearance lamp you discuss is operated as a warning lamp it becomes an item of lighting equipment outside the coverage of Standard No. 108. Therefore the fact that it flashes when activated would not violate the intent of S4.6(b). Similarly, the wiring that is installed by GM is not considered additional equipment that impairs the effectiveness of the required equipment.; The modifications you described, therefore, are not prohibited b Standard 108.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0897OpenMr. Jerry Alexander, Purchasing - Window Division, Philips Industries Inc., 4801 Springfield Street, Dayton, OH 45401; Mr. Jerry Alexander Purchasing - Window Division Philips Industries Inc. 4801 Springfield Street Dayton OH 45401; Dear Mr. Alexander: This is in reply to your letter of October 5, 1972, concerning th manufacture of storm windows for use in recreational vehicles. You refer to our letter to Mr. Bob Sanders of your company (our records show the date of the letter to be July 5) in which we outlined the requirements for glazing materials used in various locations in recreational vehicles, and ask whether storm windows used in these locations must meet the same requirements.; The answer is yes. Storm windows for use in motor vehicles must mee the same requirements as other glazing materials, according to their location in the vehicle.; I have enclosed a copy of our Response to Petitions for Reconsideratio concerning the latest amendment to Standard No. 205.; 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.