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
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ID: aiam4845OpenLiam J. Moran, Esq. Hagans, Brown, Gibbs & Moran 310 K Street, Suite 704 Anchorage, Alaska 99501; Liam J. Moran Esq. Hagans Brown Gibbs & Moran 310 K Street Suite 704 Anchorage Alaska 99501; "Dear Mr. Moran: RE: Brey v. Spalding & Evenflo Companies, Inc. You File No.: 3571 This responds to your letter to Stephen Kratzke, our Deputy Assistant Chief Counsel for Rulemaking, seeking an interpretation of the labeling requirements in Standard No. 213, Child Restraint Systems (49 CFR 571.213). More specifically, you noted that S5.5.2(g) requires add-on child restraint systems to be permanently labeled with the following: WARNING! Failure to follow each of the following instructions can result in your child striking the vehicle's interior during a sudden stop or crash. Secure this child restraint with a vehicle belt as specified in the manufacturer's instructions located Insert the location of the instruction booklet . You also noted that Standard No. 213 requires the installation instruction booklet to 'explain the primary consequences of not following the warnings required to be labeled on the child restraint system.' Parenthetically, I note that your letter erroneously identified S5.6.3 as the source of this requirement. You told Mr. Kratzke in your telephone conversation that your litigation involves an add-on child restraint system. S5.6.3 applies solely to built-in child restraint systems. However, the identical requirement is set forth for add-on child restraint systems in S5.6.1.3 of Standard No. 213. You asked whether the explanation in the instruction booklet of the primary consequences of not following the warnings labeled on the child restraint system (per S5.6.1.3) is required to be something more than the statement required to be labeled on the child restraint system (per S5.5.2(g)). The answer is no. NHTSA explicitly addressed this question in the rulemaking that established the current labeling requirements. A notice of proposed rulemaking was published on May 18, 1978 (43 FR 21470). This proposal did not include any proposed regulatory text to require a label on the child restraint system warning users about the failure to follow the instructions provided by the manufacturer. However, the preamble did have the following discussion: Comments are also requested on whether a brief explanation should be given of the primary consequences of not following the warnings and instructions provided by the manufacturer on the restraint. An example of such an explanation is that failure to attach the tether on systems having top tethers may result in the top part of the system bending forward during a crash and striking the dashboard or back of the front seat, depending on where the restraint is installed. Another example would be to explain that failure to adjust belts snugly may result in the child coming entirely out of the restraint during a crash or in crash forces being placed on the wrong portions of the child's body. (Emphasis added). 43 Fed. Reg. 21476. This request for comments was addressed solely to information that should be labeled on the restaint itself. There is no indication in the proposal that the agency sought comments on or otherwise considered requiring information in addition to this to be provided in the instuction booklet. A final rule implementing this proposal was published on December 13, 1979 (44 FR 72131). That rule included the following discussion: Many commenters (citation omitted) supported the proposed requirement that manufacturers inform consumers about the primary consequences of not following the manufacturer's warning about the correct use of the restraint. Therefore, the visible label must state the primary consequence of misusing the restraint. The same information would also have to be included in the instruction manual accompanying the restraint. (Emphasis added). 44 Fed. Reg. 72137. The regulatory language that was added to the labeling requirement for child restraints in the final rule to 'state the primary consequence of misusing the restraint' was the warning now in S5.5.2(g) of Standard No. 213. The last sentence in the above-quoted section of the preamble expressly states that the instruction booklet that accompanies the child restraint must include the same warning that is required to be labeled on the child restraint. There is, therefore, no basis for the assertion that the instruction booklet must include some warning in addition to the warning required to be labeled on the child restraint system. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam4795OpenRoger C. Fairchild, Esq. Shutler & Low 14500 Avion Parkway, Suite 300 Chantilly, VA 22021-1101; Roger C. Fairchild Esq. Shutler & Low 14500 Avion Parkway Suite 300 Chantilly VA 22021-1101; "Dear Mr. Fairchild: This responds to your inquiry about Federal Moto Vehicle Safety Standards 109, 110, 119, and 120 on tires and rim selection (49 CFR 571.109, 571.110, 571.119, and 571.120), asking about the applicability of certain provisions in the Tire and Rim Association (TRA) Year Book, which those Federal safety standards incorporate by reference. As explained below, we agree that the adjustment factors in the TRA Year Book for inflation pressures and load ratings at different speeds are not applicable in determining compliance with Federal safety standards. By way of background, the National Traffic and Motor Vehicle Safety Act, ('Vehicle Safety Act,' 15 USC 1381 et seq.) requires every new motor vehicle sold in the United States to be certified as complying with all applicable Federal motor vehicle safety standards. The Vehicle Safety Act specifies that the manufacturer must certify that each of its vehicles complies with all applicable safety standards in effect on the date of manufacture. Because of this statutory requirement, this agency does not approve any manufacturer's vehicles or offer assurances that the vehicles comply with the safety standards. Any person violating the Vehicle Safety Act by manufacturing or selling new noncomplying vehicles may be liable for potential penalties of $1,000 per violation up to $800,000. Section S4.3 of Standard 109 requires a new pneumatic tire for passenger cars to be labeled with certain information including one size designation, the maximum inflation pressure, and the maximum load rating. S6.5 of Standard 119 has similar marking requirements for tires on vehicles other than passenger cars. In particular, section 4.2.1(c) of Standard 109 and section 6.5(d) of Standard 119 require tires to be labeled with a maximum load rating not less than the lowest of any specified values in the manufacturer's submission or in a listed publication such as the TRA Yearbook, for tires of that size designation, type and each appropriate inflation pressure. For passenger car tires, these inflation pressures and load ratings are specified in tables in section one of the TRA Yearbook entitled, ''P' Type Tires Used on Passenger Cars and Station Wagons' and ''T' Type Spare Tires for Temporary Use on Passenger Cars and Station Wagons.' For tires on vehicles other than passenger cars, these inflation pressures and load ratings are specified in the tables in section 2 of the TRA Yearbook. Question One You first asked whether the Federal safety standards incorporate an independent vehicle speed adjustment factor in determining the 'vehicle normal load' and 'vehicle maximum load.' Your question was based on provisions in the TRA Year Book which apply such a vehicle load adjustment factor for certain tires rated for a maximum speed above 130 mph. As you are aware, S4.2 of Standard 110 provides that the vehicle maximum load on the tire shall not be greater than the applicable maximum load rating marked on the tire, and the vehicle normal load on the tire shall not be greater than the test load used in Standard 109's high speed performance test. You are correct that an adjustment factor based on the vehicle's maximum speed capacity is not required to be used in determining compliance with Standard 110 and 120. As you noted, Standard 110's requirement, as specified in S4.2.2, takes into account an adjustment for high speed use by requiring that the normal vehicle load on a tire must not exceed the test load used in Standard 109's high speed performance test in S5.5 (i.e. 88 percent of the tire's maximum load rating). Based on this provision and Standard No. 110's use of the terms 'vehicle maximum load' and 'maximum loaded vehicle weight,' we interpret S4.2 as applying to normal vehicle uses and not special high speed applications. In fact, incorporating a load adjustment factor based on speeds of 130 to 168 mph, as the TRA provision does, would be contrary to motor vehicle safety if it encouraged vehicle operation at speeds far exceeding safe operating speeds. Therefore, the general tables in the TRA Yearbook listing maximum inflation pressures and maximum load ratings, standing alone without applying any adjustment factor, are the applicable values in determining compliance with the Federal safety standards. Question Two You also asked about a vehicle speed adjustment factor for the inflation pressure with passenger cars. As you explained, the TRA Year Book requires that the 'speed category of the tire must match or exceed the theoretical maximum speed of the vehicle (i.e., actual maximum speed, as adjusted for tire inflation pressure using another factor specified by TRA). TRA sets forth two speed categories: speeds up to 210 km/h (130 mph) and speeds above 210 km/h (130 mph). As with the vehicle load adjustment factor which concerns normal vehicle applications, you are correct that an adjustment factor for inflation pressure based on the vehicle's maximum speed is not required to be used in determining compliance with Federal safety standards. Again, the general tables in the TRA Yearbook listing maximum inflation pressures and maximum load ratings, standing alone without applying any adjustment factor, are the applicable values in determining compliance with the Federal safety standards. Question Three You then asked about the applicability to the Federal standards of TRA's recommended adjustments for tire inflation pressure and 'service load' for tires used on trucks and buses, depending on the maximum speed capability of the vehicle. As with the adjustment factors for passenger car tires, these adjustment factors are not relevant for compliance with Standard 119 or 120. Again, the general tables in the TRA Yearbook listing maximum inflation pressures and maximum load ratings, standing alone without applying any adjustment factor, are the applicable values in determining compliance with the Federal safety standards. I hope this information is helpful. If you have any further questions, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam3050OpenHonorable Daniel K. Akaka, 415 Cannon Building, House of Representatives, Washington, DC 20515, Attention: Mr. Pat McGarey; Honorable Daniel K. Akaka 415 Cannon Building House of Representatives Washington DC 20515 Attention: Mr. Pat McGarey; Dear Mr. Akaka: This responds to your June 21, 1979, telephone request asking ho automobile dealers can determine when they must sell school buses as opposed to regular vans.; The key factors in making this determination are the purpose for whic the vehicle will be used and the passenger carrying capacity of the vehicle. The National Highway Traffic Safety Administration (NHTSA) issued the school bus safety standards in response to the Motor Vehicle and Schoolbus Safety Amendments of 1974 (Pub. L. 93-492). In defining 'schoolbus', Congress drew upon NHTSA's definition of 'bus', i.e., any motor vehicle, including a van, designed to carry more than 10 persons. Congress stated that the term 'schoolbus' means 'a passenger motor vehicle which is designed to carry more than 10 passengers ... and which the Secretary determines is likely to be significantly used for the purpose of transporting ... students to or from school or events related to such schools.' The NHTSA concluded from this mandate that any vehicle that is a bus and will be used on a regular and recurring basis to transport school children must comply with school bus safety standards. To effect this conclusion, the agency issued a definition of 'schoolbus' which is 'a bus that is sold or introduced in interstate commerce, for purposes that include carrying students to or from school or related events....'; The effect of the 1974 amendments and the agency's definition is t require any new bus that is sold to transport school children on a regular basis to comply with the safety standards. Compliance is required whether a bus is used regularly to transport students 100 percent of the time or whether it regularly transports students only 10 percent of the time while otherwise transporting adults.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1597OpenMr. Bernard E. Wuthrich, Pan Commercial, 108 Grove Street, Worcester, MA., 01605; Mr. Bernard E. Wuthrich Pan Commercial 108 Grove Street Worcester MA. 01605; Dear Mr. Wuthrich: This is in reply to your letter of August 27, 1974 asking for clarification of the National Traffic and Motor Vehicle Safety Act.; You are correct in your impression that under section 103(d) of the Ac 'no state legislation can be more stringent than the Federal ruling.' Under paragraph S4.1.126 of Standard No. 108, effective October 14, 1974, 'a motor-driven cycle whose speed attainable in 1 mile is 30 mph or less need not be equipped with turn signal lamps.' This means that as of that date, only motor-driven cycles whose maximum speed exceeds 30 mph are required to be manufactured with turn signal lamps. Lower- speed cycles may continue to be provided with them if the manufacturer chooses, but a State cannot require him to do so. This is the result of the preemptive effect of section 103(d).; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3400OpenMr. Brian Gill, Manager, Certification Department, American Honda Motor Co., Inc., 100 W. Alondra Blvd., P.O. Box 50, Gardena, CA 90247; Mr. Brian Gill Manager Certification Department American Honda Motor Co. Inc. 100 W. Alondra Blvd. P.O. Box 50 Gardena CA 90247; Dear Mr. Gill: This responds to your recent letter regarding an emergency lockin retractor design which incorporates a secondary locking mechanism that is activated by webbing movement. The primary locking mechanism of the retractor is sensitive to both vehicle deceleration and webbing movement. You ask whether the secondary locking mechanism must be tested separately for compliance with Safety Standard No. 209, or whether it is sufficient that the retractor as a whole comply with the standard.; The secondary locking mechanism does not have to be tested separatel since it would be viewed by the agency as a voluntary system. I am enclosing a letter of interpretation on this same subject which was issued by the agency in February 1981 to Toyota Motor Company. I am also enclosing a copy of a letter of interpretation issued to the United States Testing Company regarding the application of Safety Standard No. 209 to dual- sensitive retractors. This second letter might also be of interest to you since you state that the primary locking mechanism on the Honda retractor is sensitive to both vehicle deceleration and webbing movement.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3953OpenMr. Ernest Astle, Purchasing Agent, Alco Manufacturing Company, P.O. Box 724, Logan, UT 84321; Mr. Ernest Astle Purchasing Agent Alco Manufacturing Company P.O. Box 724 Logan UT 84321; Dear Mr. Astle: This responds to your letter to Steve Kratzke of my staff asking for a interpretation of the requirements of Standard No. 302, *Flammability of interior materials* (49 CFR 571.302). Specifically, you asked if the requirements of that standard apply to aftermarket seat covers. While the standard applies only to new motor vehicles, its requirements do indirectly affect some aftermarket seat covers. As explained in greater detail in the attached letter to Mr. Cederbaum regarding the same issue, rendering inoperative equipment or elements of design installed in a vehicle pursuant to the Federal motor vehicle safety standards is prohibited if done by certain commercial enterprises, but is permitted if done by the vehicle owner. Thus, if a seat cover in a complying vehicle were replaced with a noncomplying seat cover by one of those enterprises, that act would violate the above prohibition. The same act, if done by the owner, would not be a violation.; Should you need further information or have any further questions i this area, please contact Mr. Kratzke at this address or by telephone at (202) 426-2992.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2641OpenMr. Samuel W. Alderson, President, Humanoid Systems, 747 East 223rd Street, Carson, CA 90745; Mr. Samuel W. Alderson President Humanoid Systems 747 East 223rd Street Carson CA 90745; Dear Mr. Alderson: This responds to your June 3, 1977, request for confirmation that 572.7(b) of Part 572, *Anthropomorphic Test Dummy* (49 CFR 572), specifies a minimum time period during which the pendulum used in testing may not reverse direction rather than an exact time.; Your interpretation is correct. The specification that the pendulu 'shall not reverse direction until T=123 ms' means that reverse travel must not occur earlier than 123 milliseconds after chordal displacement begins. The agency believes that this language can be improved and intends to clarify it at the next opportunity.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5184OpenMr. Berkley C. Sweet Executive Vice President School Bus Manufacturers Institute 7508 Ben Avon Road Bethesda, MD 20817; Mr. Berkley C. Sweet Executive Vice President School Bus Manufacturers Institute 7508 Ben Avon Road Bethesda MD 20817; "Dear Mr. Sweet: This responds to your letter requesting definitions o primary, preprimary, and secondary school students. You write in response to our July 28, 1992 letter to you in which we state that the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1581, et seq. (Safety Act), defines a school bus as a vehicle that is 'likely to be significantly used for the purposes of transporting primary, preprimary, or secondary school students to or from such schools or events related to such schools' (emphasis added). The terms primary, preprimary, and secondary school are not defined in the Safety Act or in the legislative history of the Act. However, NHTSA has historically interpreted 'preprimary school' to refer to kindergarten, nursery schools and Head Start facilities. 'Primary school' refers to elementary school, and 'secondary school' refers to high school. I have enclosed a copy of our March 20, 1990 letter to Mr. Cadwallader Jones that discusses whether various institutions (e.g., church schools and colleges) are considered 'schools' under the Safety Act. The various states may have their own definitions of a 'school' for determining the use requirements for school vehicles. Therefore, you should check with the state where questions of school vehicle use are at issue. I hope the above information will be of assistance to you. If you have any further questions regarding this matter, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0386OpenStephen F. Hefner, Esq, Nance, Caston, Hefner and Green, Attorneys-At-Law, 421 North Crockett Street, Sherman, TX 75090; Stephen F. Hefner Esq Nance Caston Hefner and Green Attorneys-At-Law 421 North Crockett Street Sherman TX 75090; Dear Mr. Hefner: This is in reply to your letter of May 20, 1971, concerning a marketin practice used by your client, Hale Trailer Sales, Inc., which consists of allowing purchasers of new trailers to specify that the trailer be delivered with either new or used tires. When used tires are chosen, you indicate that they are for the limited purpose of delivering the trailer to the purchaser, and are usually replaced by him with other tires. You further indicate that this practice is widespread in the particular industry.; You ask in your letter whether the Tire Identification an Recordkeeping regulations (49 CFR Part 574) apply to the trailers that are sold equipped with used tires. The answer to this question is no. However, as you apparently realize, trailers sold with new tires that have been manufactured on or after May 22, 1971, are subject to the regulation.; Your letter also discusses the possibility of future requirements fo trailer tires, and suggests three possible courses of action under such requirements by which trailers might be sold with used tires. An Advance Notice of Proposed Rulemaking concerning multipurpose passenger vehicle, truck, bus, motorcycle, and trailer tires was published October 14, 1967, (32 F.R. 14279) and a public meeting was held on the subject in June 1970. Since that time there has been no public issuance concerning this matter, and it is thus impossible to send you the proposed rule you requested. The matter is under active consideration within the agency, however, and the proposed requirements should be issued in the near future.; The proposals will solicit comments from interested persons, which wil be considered before any final regulations are issued. Your comments and any additional suggestions you might have would be appreciated in response to these proposals.; If you have additional questions, please feel free to write. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam1691OpenMr. David F. Berry, Works Manager, Birmingham Manufacturing Company, Inc., P. O. Drawer 289, Springville, AL 35146; Mr. David F. Berry Works Manager Birmingham Manufacturing Company Inc. P. O. Drawer 289 Springville AL 35146; Dear Mr. Berry: This is in acknowledgment of your Defect Information Report, i accordance with the defect reporting regulation, Part 573.; The Defect Information Report involves: some trailers equipped wit Standard Forge axles which may have defective brake shoes.; The following National Highway Traffic Safety Administratio identification number has been assigned to the campaign *74-0224*. The first quarterly status report for this campaign is required to be submitted by February 5, 1975. Please refer to the above number in all future correspondence concerning this campaign.; The letter which you have sent to the owners of the subject vehicle does not meet the requirements of Part 577(49 CFR), the Defect Notification regulation. It is therefore necessary that you send a letter which conforms to Part 577 to those owners who have not yet had their vehicles corrected at this time or indicated their intention to do so. A copy of your revised letter should also be sent to this office.; A copy of Part 577 is enclosed. It might be helpful to point out tha Part 577.4(a) and (b) should be quoted exactly. In paragraph (b) the vehicle manufacturer determines that a defect exists in his vehicles even though a specific component may be the cause of the defect.; The reference to motor vehicle equipment in the regulation only applie to equipment campaigns where vehicles are not directly involved. Part 577.4(d) requires a statement that vehicle crash without prior warning may occur in cases where this statement is true. If you desire further information, please contact Messrs. W. Reinhart or James Murray of this office at (202) 426-2840.; Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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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.