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: aiam1898OpenMr. Evan Hammond, Manager - Central Engineering, Trailmobile Technical Center, 5570 Creek Road, Cincinnati, OH 45242; Mr. Evan Hammond Manager - Central Engineering Trailmobile Technical Center 5570 Creek Road Cincinnati OH 45242; Dear Mr. Hammond: This is in response to your letter of April 14, 1975, in which yo described two factors that you see as problems in the completion of air-braked trucks in accordance with Standard 121, by final-stage manufacturers.; The first problem you cited was that without knowing how this agenc will require air-braked trucks to be loaded for test purposes, specifically whether we will load them according to the chassis manufacturer's specifications, the final-stage manufacturer does not have a basis for certification. The answer to this implied question is that the NHTSA will use the chassis manufacturer's loading limitations for purposes of determining compliance. We agree that in many cases there is no practicable way for a final- stage manufacturer to ensure compliance other than relying on the chassis manufacturer's statements in the Part 568 document, and these statements are contingent on the loading conditions.; Secondly, you argued that 'If a tested and certified vehicle cannot b stopped in actual use in the required distance because the real load has a center of gravity higher than an unrealistic test load, an unsafe vehicle has been created, even though it complies to the safety standard.'; We completely disagree with that position, and know of no facts t support its validity. We have no reason to believe that vehicles that conform to Standard 121 will be unsafe when loaded the same as comparable pre-121 vehicles. In fact, we have much reason to believe they will be safer than pre-121 vehicles, with stronger, better modulated brakes, and in many cases stronger front suspensions to carry the forces imposed by high-CG loads in a braking situation. The required stopping distances are part of a large and complex package of test requirements, whose conditions and procedures must be precisely specified to meet statutory requirements of objectivity. They are designed to give rise to vehicles whose braking systems use the best of modern technology to provide excellent braking performance under a wide range of loading and environmental conditions. There is no implication from the standard that a vehicle that, under certain loading conditions, does not stop in the specified distance is necessarily unsafe. If the NHTSA discovers vehicles that are truly unsafe when normally loaded, because of unusual handling difficulties, for example, it will proceed against them under its safety-related defect jurisdiction.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam5072OpenThe Honorable John D. Dingell Chairman, Committee on Energy and Commerce U.S House of Representatives Room 2125, Rayburn House Office Building Washington, DC 20515-6115; The Honorable John D. Dingell Chairman Committee on Energy and Commerce U.S House of Representatives Room 2125 Rayburn House Office Building Washington DC 20515-6115; Dear Chairman Dingell: Thank you for your letter of September 17, 1992 enclosing correspondence from Mr. Aaron Gordon concerning seat belts on school buses. You requested comments on Mr. Gordon's letter and on H.R. 896, a bill referred to in Mr. Gordon's letter. The issue of safety belts on school buses is an important topic which the National Highway Traffic Safety Administration (NHTSA) has thoroughly studied for many years. School bus transportation has been and continues to be one of the safest forms of transportation in America. Every year, approximately 370,000 public school buses travel approximately 3.5 billion miles to transport 22 million children to and from school and school-related activities. Since NHTSA began tracking traffic fatalities in 1975, an average of 16 school bus occupants per year have sustained fatal injuries. While each of these fatalities is tragic, the number of school bus occupant fatalities is small compared to the number of occupant fatalities to children in other types of vehicles. For example, in 1989 there were 5,287 deaths among children aged five to 18 in vehicles other than school buses. In 1977, NHTSA issued Federal motor vehicle safety standard No. 222, School Bus Passenger Seating and Crash Protection, which established minimum crash protection levels for occupants of all school buses. For large school buses, those with a gross vehicle weight rating (GVWR) above 10,000 pounds, the standard requires occupant protection through a concept called 'compartmentalization' -- strong, well-padded, well-anchored, high-backed, evenly spaced seats. The effectiveness of 'compartmentalization' has been confirmed by independent studies by the National Transportation Safety Board (NTSB) and the National Academy of Sciences (NAS). Under the current requirements of Standard No. 222, small school buses, those with a GVWR of 10,000 pounds or less, must provide 'compartmentalization' and be equipped with lap or lap/shoulder belts at all designated passenger seating positions. The agency believes that safety belts are necessary in addition to 'compartmentalization' in small school buses because of their smaller size and weight, which are closer to that of passenger cars and light trucks. In 1987, the NTSB completed a study of the crashworthiness of large school buses, and concluded that most school bus occupant fatalities and serious injuries were 'attributable to the occupants' seating position being in direct line with the crash forces. It is unlikely that the availability of any type of restraint would have improved their injury outcome.' In 1989, NAS completed a study of means to improve school bus safety and concluded that 'the overall potential benefits of requiring seat belts on large school buses are insufficient to justify a Federal requirement for mandatory installation. The funds used to purchase and maintain seat belts might better be spent on other school bus safety programs and devices that could save more lives and reduce more injuries.' The NAS pointed out that since children are at greater risk of being killed in school bus loading zones (i.e., boarding and leaving the bus) than on board school buses, 'a larger share of the school bus safety effort should be directed to improving the safety of bus loading zones.' A summary of the NAS report is enclosed. In response to the recommendations from the NAS study, NHTSA has initiated several rulemaking actions, such as improvements to school bus visibility by the driver and requiring stop signal arms on school buses, designed to improve the safety of students in school bus loading zones. Besides the actions taken in response to the NAS study, NHTSA has initiated several other rulemaking activities to improve further the safety of school buses, e.g., increasing the number of emergency exits, establishing wheelchair securement/occupant restraint requirements, and improving the body joint strength requirements. While there are no Federal requirements for safety belts on large school buses, states are free to install them if they feel it is in the best interest in their state. However, as noted in the NAS report, if the safety belts are to be beneficial, 'states and local school districts that require seat belts on school buses must ensure not only that all school bus passengers wear the belts, but that they wear them correctly.' In summary, the safety record of school buses is outstanding. As such, there is no compelling evidence to suggest that safety belts would provide even higher levels of occupant crash protection. Also, the agency agrees with the conclusion from the NAS report, that there is insufficient reason for a Federal mandate for safety belts on large school buses. I hope you find this information helpful. Sincerely, Marion C. Blakey Enclosure cc: Mr. Aaron Gordon; |
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ID: aiam5588OpenThe Honorable Chuck Chvala Wisconsin State Senator State Capitol P. O. Box 7882 Madison, WI 53707-7882; The Honorable Chuck Chvala Wisconsin State Senator State Capitol P. O. Box 7882 Madison WI 53707-7882; Dear Senator Chvala: This responds to a letter from U.S. Senato Russell D. Feingold on your behalf, asking whether a pending redefinition of Wisconsin's 'school bus' definition would violate Federal law. Senator Feingold contacted the National Highway Traffic Safety Administration (NHTSA) because our agency administers the Federal requirements for school buses. I appreciate this opportunity to address your concerns. As explained below, my review leads me to conclude that Wisconsin's contemplated redefinition of a school bus would not conflict with Federal law, insofar as the redefinition relates to the operation of school buses. However, an area of possible conflict relates to the requirements for mirrors on school buses. By way of background information, Chapter 301 of Title 49 of the U.S. Code, authorizes NHTSA to issue Federal motor vehicle safety standards (FMVSS's) applicable to new motor vehicles and motor vehicle equipment. In 1974, Congress directed NHTSA to require new school buses to meet FMVSS's on specific aspects of school bus safety, including floor strength, seating systems, and crashworthiness. The legislation requires each person selling a new 'school bus' to ensure that the vehicle is certified as meeting the school bus FMVSS's. Following the first retail purchase, the use of vehicles becomes a matter of state regulation. NHTSA defines a 'school bus' as a 'bus' that is sold for purposes that include carrying students to and from school or related events, and defines a 'bus' as a vehicle designed to carry 11 or more persons. 49 CFR 571.3. We understand that the new definition contemplated by Wisconsin would exclude some vehicles that are school buses under our definition. Information from Mr. Doug Burnett of your staff indicates that the new definition would define a school bus as 'a motor vehicle which carries 16 or more passengers (in addition to the operator).' Thus, a motor vehicle that can carry 11-16 persons (including the driver) would be a 'school bus' for Federal purposes, but apparently not for Wisconsin's purposes. Since the States, and not NHTSA, regulate the use of vehicles, the inconsistency would be immaterial with regard to requirements adopted by Wisconsin pertaining to the use of school buses. Wisconsin may set the operational requirements for those vehicles the State defines as 'school buses' without regard to our school bus definition. However, the inconsistency would matter at the point of sale of a new school bus. The FMVSS's specify requirements for school buses that do not apply to other buses. See, e.g., 49 CFR part 571.222, School bus passenger seating and crash protection. A decision by Wisconsin to adopt a definition other than the Federal definition of a school bus has no effect on the application of the Federal school bus safety standards to a vehicle. Any person selling a new 'bus' (a vehicle designed to carry 11 or more persons) to a school must sell a certified 'school bus,' regardless of whether the vehicle is considered a school bus under Wisconsin law. The vehicle would have to be equipped with the safety features NHTSA requires for school buses. The information provided by Mr. Burnett indicates that Wisconsin would redefine 'school bus' for two purposes. First, Wisconsin would prohibit the operation of a 'school bus'--a vehicle with a capacity of 17 persons (including the driver)--unless the bus has a specific type of mirror. (Section 347.40) As explained above, this requirement would not affect NHTSA's requirement that vehicles considered to be 'school buses' under our definition must be equipped with the mirrors and other safety features we require for school buses, even if the vehicles are not 'school buses' under Wisconsin law. Chapter 301 further provides that a Federal standard preempts any state or local standard applicable to the same aspect of performance that is not identical to the Federal standard. 49 U.S.C. 30103(b). A State standard for mirrors that is not identical to the Federal standard is preempted unless it imposes a higher level of safety and is applicable only to vehicles procured for the State's own use (e.g., public school buses). Wisconsin's requirements for school bus mirrors could be preempted, depending on the type of mirror required and whether the vehicles equipped with it are public buses. We understand that the second purpose of Wisconsin's contemplated redefinition of a school bus is to require privately-owned vehicles carrying 15 or fewer students to be insured by a policy providing specified minimum coverage. (Section 121.555). This provision concerns matters wholly within State law and would not conflict with Federal law. I hope the above information is helpful to you. If you have any further questions or need additional information, please contact me or Dorothy Nakama of my staff at this address, or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel cc: The Honorable Russell D. Feingold United States Senate 502 Hart Senate Office Building Washington, D.C. 20510; |
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ID: aiam0270OpenMr.Stanley C. Nickell, Attorney at Law, Northeast Kentucky Area Development Council, Inc., Room 102, Courthouse, Greenup, Kentucky 41144; Mr.Stanley C. Nickell Attorney at Law Northeast Kentucky Area Development Council Inc. Room 102 Courthouse Greenup Kentucky 41144; Dear Mr. Nickell: This is in reply to your letter of September 28, 1970, to Mr. Lowell K Bridwell, Administrator, Federal Highway Administration, asking for a definition of 'blemished,' 'second,' and 'farm use only,' which has been referred to this office for reply.; Tire manufacturers are required to certify that their product complie with the Federal Motor Vehicle Safety Standard No. 109, and do so by labeling each tire they certify with the symbol 'DOT.' Tires that are certified by the manufacturer and marked 'seconds' are not necessarily unsafe, as the 'second' may be due to a cosmetic defect not affecting the tire's performance.; Sometimes a tire manufacturer will make a tire that he believes i defective in a way that affects the safety of the tire. Often, that manufacturer will mark the tire 'farm use only' or 'non-highway use' and then sell it. In such instances, he is required to remove the DOT symbol.; We do not have a definition for 'blemished.' We have enclosed a copy of an amendment to the passenger car tir standard (No. 109) that contains the definition for 'non-highway use tires' which is applicable to 'farm use only' and 'tire identification and recordkeeping' which is applicable to 'manufacturer's marks on tires.'; Thank you for your interest in the Motor Vehicle Safety Program. Sincerely, Francis Armstrong, Director, Office of Compliance, Moto Vehicle Programs; |
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ID: aiam4233OpenThomas F. McRedmond, State of Tennessee, Department of Revenue, Andrew Jackson State Office Building, Nashville, TN 37242; Thomas F. McRedmond State of Tennessee Department of Revenue Andrew Jackson State Office Building Nashville TN 37242; Dear Mr. McRedmond: I have reviewed your letter of November 14, 1986, and the Tennesse Certificate of Title and Application for Certificate of Title which you forwarded to me. As I advised you previously, the Tennessee Certificate of Title may not be used in lieu of a separate odometer disclosure statement.; Federal regulation, 49 C.F.R. S580.4(e), requires that the transfere shall acknowledge receipt of the disclosure statement by signing it. Therefore, the signature must be on the same document with the disclosure information and not on a separate piece of paper. The National Highway Traffic Safety Administration considers the signature to be essential. In addition to being an acknowledgement of receipt, it prevents the purchaser from later alleging that he was not informed of the mileage. Furthermore, the buyer's signature is important to investigative and prosecutional efforts.; I urge you to notify Tennessee dealers and distributors that thei failure to issue and/or return a separate odometer disclosure statement may subject them to civil and criminal penalties.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1031OpenMr. Louis C. Lundstrom, General Motors Corporation, Warren, MI 48090; Mr. Louis C. Lundstrom General Motors Corporation Warren MI 48090; Dear Mr. Lundstrom: This is in reply to your letter of February 8, 1973, concerning the us of a 'comfort clip' on the shoulder belt portion of GM's 1974 seat belt system.; In response to questions from other manufacturers concerning the use o high friction buckles in continuous loop belt systems, we have indicated that the requirement of Standard 208 that the belts adjust to fit specified occupants precludes the use of such buckles. In the case of systems with separate lab and shoulder retractors, however, the shoulder belt does not affect the tension in the lap belt and therefore does not present the risk of submarining that exists with the single loop systems. Accordingly, we are of the opinion that a comfort clip would be acceptable under S7.1.1 of the standard, so long as the shoulder belt is otherwise capable of adjustment as required by S7.1.1.; At a meeting with you on this subject on January 24, 1973, the NHTS expressed its concern about possible reductions in shoulder belt effectiveness due to excessive belt slack. On the whole, we find that this possibility is more than offset by the prospects of greater usage due to the added convenience of the system with the clip. However, we strongly support your proposal to include instructions for the use of the clip both on the clip itself and in the owner's manual.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4663OpenThe Honorable Bud Shuster U.S. House of Representatives Washington, DC 20515; The Honorable Bud Shuster U.S. House of Representatives Washington DC 20515; Dear Mr. Shuster: Thank you for your inquiry on behalf of you constituent, Mr. Lester Hoover. Mr. Hoover requested information about laws that cover the branding of tires that are not first quality. In addition, he asked whether there is any way to apply such a law to other consumer goods such as batteries. This inquiry has already been referred to the Federal Trade Commission (FTC), which sent you a letter dated October 16, 1989 explaining its tire labeling regulations. The FTC's letter also indicated that this agency's tire labeling regulations might be of interest to Mr. Hoover. Let me begin by explaining that the National Highway Traffic Safety Administration has promulgated regulations related to tires. In particular, Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires, applies to new tires for use on passenger cars, Standard No. 119, New Pneumatic Tires for Vehicles Other Than Passenger Cars, applies to new tires for use on vehicles other than passenger cars, Standard No. 117, Retreaded Pneumatic Tires, applies to retreaded tires for use on passenger cars, and Part 569, Regrooved Tires, applies to all regrooved tires. Each of these regulations includes some labeling requirements. The National Traffic and Motor Vehicle Safety Act requires that every manufacturer certify that each of the tires it produces complies with these standards, including the labeling requirements. Thus, even a tire identified as something like 'blemished' or 'out-of-round' must be certified as complying with all provisions of the applicable safety standard(s). None of the regulations administered by this agency require, or establish any standards for, the identification of tires as something other than 'first quality.' If some Federal regulation exists that requires the identification of tires as something other than 'first quality,' it would be promulgated by the FTC under that agency's authority to regulate unfair and deceptive trade practices. If the FTC does not have any such regulation, I am not aware of any other Federal agency that would have authority in this area. Similarly, I am not aware of any such labeling regulations that could be applied to consumer goods such as batteries. I hope you find this information helpful. Please let me know if you have any further questions or concerns in this area. Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam4399OpenMs. Deborah L. Brown, Office Manager, Callaway Engineering, 3 High Street, Old Lyme, CT 06371; Ms. Deborah L. Brown Office Manager Callaway Engineering 3 High Street Old Lyme CT 06371; Dear Ms. Brown: This responds to your letter seeking confirmation of your understandin of Standard No. 208, *Occupant Crash Protection*, as it relates to convertibles. You asked that we verify your understanding in two specific areas. These were:; 1. NHTSA has decided to exempt convertibles from the automati restraint requirements set forth in Standard No. 208 for passenger cars during the phase-in period (September 1, 1986 to August 31, 1989).; This statement is correct. In a final rule published October 17, 198 (51 FR 37028, copy enclosed), the agency announced its decision to exempt convertibles from the automatic restraint requirements for passenger cars during the phase-in period. In a subsequent notice terminating further rulemaking on this subject, the agency announced its decision to retain the automatic restraint requirements for convertibles manufactured on or after the first day after the end of the phase-in period, i.e., September 1, 1989 (52 FR 10122, March 30, 1987, copy enclosed). Thus, convertibles manufactured on or after that date will be subject to the same requirements as all other passenger cars.; You also asked about the exact requirements for restraints i convertibles. Prior to September 1, 1989, convertibles must comply with the requirements of section S4.1.2.3.2 of Standard No. 208. However, convertible manufacturers may, at their option, choose to certify that convertibles manufactured before September 1, 1989, comply with the automatic restraint requirements set forth in section S4.1.2.1 of Standard No. 208. After September 1, 1989, Standard No. 208 draws no distinction between convertibles and other passenger cars. Section S4.1.4 of Standard No. 208 provides that all passenger cars, including convertibles, manufactured on or after September 1, 1989, shall comply with the automatic restraint requirements of S4.1.2.1, unless section S4.1.4 is rescinded pursuant to S4.1.5.; 2. A manufacturer does not have to count convertibles as part of it passenger car production volume when determining its annual production during the phase-in period.; This statement is also correct. The October 17, 1986 amended Standar No. 280 and 49 CFR Part 585, *Automatic Restraint Phase-In Reporting*, to explicitly provide that manufacturers may exclude their production of convertibles that do not comply with the automatic restraint requirements of S4.1.2.1 of Standard No. 208 from the calculation and reporting of annual production during the phase-in period.; If you have any further questions on this subject, please feel free t contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992 (sic).; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1461OpenMr. J. C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. J. C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold: This is in reply to your November 21, 1973, petition for amendment o Federal Motor Vehicle Safety Standard No. 215, *Exterior Protection*, requesting that a more specific bumper pendulum impact pattern be adopted.; The revisions you have proposed could result in designs with less tha required protection in areas outside those specified by Ford. Although the impact points suggested by Ford may constitute an adequate testing pattern for Ford vehicles, they may not be adequate for all other manufacturers' vehicle designs.; The necessity of detecting weak points that you cite is one of the mai goals of the safety standards. To the extent that Ford is confident that such 'searching' is unjustified (because there is no reasonable probability of finding a nonconformity), there is no necessity to search. Structural analysis of each bumper design based upon previous test experience should enable the vehicle manufacturer to determine the critical areas for testing. The manufacturer is free to determine, for example, on sufficient data, that all models need not be tested where the basic bumper design, including the energy absorption unit, is utilized in the models. A further reduction in the need for testing can be realized by a retention of the same bumper designs from year to year.; For these reasons, the NHTSA must deny your request for a more specifi demonstration technique.; Sincerely, James B. Gregory, Administrator |
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ID: aiam1174OpenMr. Edward W. Gaylord, Vice President, Gaylord Products, Inc., 1918 Prairie Avenue, Chicago, IL 60616; Mr. Edward W. Gaylord Vice President Gaylord Products Inc. 1918 Prairie Avenue Chicago IL 60616; Dear Mr. Gaylord: This is in reply to your letter of June 26, 1973, to Mr. Vinson of thi office, enclosing the proposed Panther certification label, and asking whether it conforms to our requirements. The label is arranged as a narrow horizontal strip with two lines of type.; The label contains the required statements in the required order, an thus fulfills the requirements.; Sincerely, Richard B. Dyson, Assistant 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.