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: aiam4539OpenMr. Earl Dahl The Goodyear Tire & Rubber Co. Akron, OH 44316-0001; Mr. Earl Dahl The Goodyear Tire & Rubber Co. Akron OH 44316-0001; "Dear Mr. Dahl: This responds to your letter of June 1, 1988, seekin an interpretation of 49 CFR Part 574, Tire Identification and Recordkeeping. Specifically, you asked whether Goodyear could engrave its mold for the Tire Identification Number with a style of characters that was not specifically authorized in the Notes following Figure 1 of 574.5. Note 1 to Figure 1 of Part 574 specifies only four different print types which may be used for the DOT symbol and tire identification number. The style of print that you wish to use is not one of these designated styles. Nevertheless, Note 4 to Figure 1 states that other print types will be permitted if approved by the National Highway Transportation Safety Administration (NHTSA). The agency has examined the print type shown in the diagram attached to your letter and has no objections to your company printing the required information in the print type you submitted. You should be aware that in the final rule establishing Part 574 (35 FR 17257, November 10, 1970), NHTSA explained that the reason for specifying only four print types which would be acceptable without advance agency approval was to ensure that the information would be easily readable by all persons. The print type that you submitted is easily readable and thus satisfies our concerns in that regard. Accordingly, NHTSA approves your print type. Sincerely, Erika Z. Jones Chief Counsel "; |
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ID: aiam2814OpenMr. E. M. Ryan, Chief Design Engineer, Ward Industries, Inc., P.O. Box 849, Highway 65 South, Conway, AR 72032; Mr. E. M. Ryan Chief Design Engineer Ward Industries Inc. P.O. Box 849 Highway 65 South Conway AR 72032; Dear Mr. Ryan: This responds to your April 27, 1978, letter asking whether a sampl certification label that you submitted complies with the National Highway Traffic Safety Administration's (NHTSA) Part 567, *Certification*.; Military vehicles are exempted from compliance with Federal safet standards. Therefore, the application of the safety standards to these vehicles is a matter of contract between a manufacturer and the military. Since the NHTSA does not mandate Federal safety standards for these vehicles, it is not necessary to put certification labels on them. If you choose to include a label with a vehicle, the label would not be required to comply with any Federal regulations.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0829OpenMr. J. W. Kennebeck, Manager, Safety & Development, Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Mr. J. W. Kennebeck Manager Safety & Development Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Kennebeck: This is in reply to your letter of June 26, 1972, on the subject of th conformity of the Volkswagen shoulder belt/knee bar system to the requirements of Standard No. 208. I apologize for our delay.; Your first question is whether the system would meet the requirement for a fully passive system under S4.1.2.1 and S4.1.3 if it were adjusted automatically and met the frontal and lateral crash protection requirements of S5.1 and S5.2 and if the vehicle conformed to Standard 216. Our reply is that a passive seat belt system of the type you describe would appear to satisfy the requirements of S4.1.2.1 and S4.1.3. It would also, however, be required to meet the requirements of S4.5.3. We cannot determine from your description whether the system is capable of fitting the range of occupants specified in S7.1, as required by S4.5.3.3.; Your second question concerns that possibility that the system could b used, with the shoulder belt either active or passive, to meet the second or third option for passenger cars manufactured between August 15, 1973, and August 15, 1975. You point to two variances between the Volkswagen system and the system contemplated by these options. S4.1.2.2 requires the installation of a Type 1 seat belt, whereas the Volkswagen system contains only a shoulder belt and a knee bar. S4.1.2.3 specifies either a Type 1 or a Type 2 seat belt assembly, neither of which is found in the Volkswagen system. It is our opinion that these variances are such that an amendment of the standard would be required to permit the use of the Volkswagen system under either S4.1.2.2 or S4.1.2.3.; With reference to both the passive system discussed in your firs question and a petition for rulemaking in connection with your second, we are particularly concerned with the actual crash performance of a single diagonal belt restraint as opposed to the Type 1 or Type 2 belts permitted in Standard No. 208. The injury criteria presently included in Standard No. 208 may not differentiate between restraint systems with good crash force distribution, such as the air cushion, and those such as the single diagonal belt which could poorly distribute loads on real human occupants. Accordingly, we would appreciate your sending us accident data describing experience with the European-type single diagonal belt.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3706OpenMr. C. J. Johnston, Manager, Product Reliability, The BF Goodrich Company, Tire Group, 500 South Main Street, Akron, OH 44318; Mr. C. J. Johnston Manager Product Reliability The BF Goodrich Company Tire Group 500 South Main Street Akron OH 44318; Dear Mr. Johnston: 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: aiam0080OpenMr. R. A. Moynihan, Sales Manager - Truck Equipment, ATECO Equipment Company, Post Office Box 8741, Pittsburgh, PA 15221; Mr. R. A. Moynihan Sales Manager - Truck Equipment ATECO Equipment Company Post Office Box 8741 Pittsburgh PA 15221; Dear Mr. Moynihan: This is in further reply to your letter to Mr. Slagle dated March 8 1968, in which you ask for information as to your company's responsibility under the National Traffic and Motor Vehicle Safety Act and regulations issued pursuant to the Act.; As I understand the description of the modification your company make to trucks the only standard now in effect that is applicable is Standard No. 205, the glazing standard. Therefore, the glass that you install in place of the original glass in the truck cab would have to comply with this standard.; Your company might also be affected by the enclosed Advanced Notice o Proposed Rulemaking. Your particular attention is directed to Docket No. 2-12 which would, if finalized, make the standard concerning anchorage of seats (No. 207) applicable to trucks.; Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel |
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ID: aiam2547OpenMr. Dennis J. Mahr, Attorney at Law, 232 Davidson Building, Sioux City, IA 51101; Mr. Dennis J. Mahr Attorney at Law 232 Davidson Building Sioux City IA 51101; Dear Mr. Mahr: This responds to your February 23, 1977, letter asking whether For Motor Company's record keeping practices conform to the regulations of the National Highway Traffic Safety Administration (NHTSA).; Your letter refers to material allegedly destroyed by Ford pertainin to accident and recall information involving headlamp concealment devices in 1967 Mercury Cougars. The NHTSA is unable to ascertain from the information that you have submitted whether or not Ford's record keeping violates our requirements.; The NHTSA implemented on August 20, 1974, a regulation requirin manufacturers to retain for a period of 5 years records generated or acquired after August 15, 1969, concerning motor vehicle malfunctions that may be related to motor vehicle safety (49 CFR 576, *Record Retention*). Since the recall to which you refer occurred prior to this regulation, it is possible that the identified records were generated or acquired prior to the promulgation of the regulation, and therefore, the destruction of these records would not necessarily mean that Part 576 was violated.; The NHTSA has a public file concerning the headlamp concealment device referred to in your letter. This file containing 26 pages of information will be sent to you by our Technical Reference Branch under separate cover.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5282OpenMs. Lisa A. Norris P.O. Box 41 Mandeville, LA 70470; Ms. Lisa A. Norris P.O. Box 41 Mandeville LA 70470; Dear Ms. Norris: This is in reply to your letter of December 1, 1993 to Robert Hellmuth of this agency. You have written us questioning the disconnection of your original equipment center highmounted stop lamp when an aftermarket spoiler with lamp was installed on your Honda. American Honda has referred you to us, referencing an interpretation by our former Chief Counsel, Paul Jackson Rice. I enclose a copy of Mr. Rice's letter of August 31, 1990, to David Holscher which sets forth the agency's views on this subject. These views remain our position. The disconnecting of your lamp appears permitted under Federal Motor Vehicle Safety Standard No. 108 according to this interpretation. Because Federal authorities do not interpret the laws of the individual States, we are unable to comment on the Louisiana provisions that you paraphrase, except to note that 'tail lights', as you refer to them, are not 'stop lamps' under Standard No. 108. Taillamps are another item of lighting equipment and have no relevance to the wiring of the center highmounted stop lamp. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam5328OpenMr. Perry McGlothan Quality Assurance Test Specialist Century Products Company 9600 Valley View Road Macedonia, OH 44056; Mr. Perry McGlothan Quality Assurance Test Specialist Century Products Company 9600 Valley View Road Macedonia OH 44056; Dear Mr. McGlothan: This responds to your letter to me about the hea impact protection and protrusion limitation requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 213, Child Restraint Systems. We received under separate cover the three child seats you sent for illustration purposes, samples of Models 4560, 4590 and the STE 1000. You discuss in your letter a new method you would like to use to attach the head impact protection foam to the child restraint shell. The foam would be attached to the shell by means of two push-in pins, each 1/2 inch in length and with a 3/4 inch diameter head, as distinguished from the padding being glued to the shell as in the past. You stated that this change would better secure the foam padding to the shell and help your manufacturing process. You asked us whether the new method would meet the head impact protection requirement of S5.2.3 (for restraints recommended for children weighing less than 20 pounds) and the protrusion limitations of S5.2.4. As you know, the National Traffic and Motor Vehicle Safety Act establishes a self-certification system under which manufacturers are responsible for ensuring that their products comply with all applicable FMVSSs. We do not approve, endorse, or give assurances of compliance of any product. NHTSA may examine the manufacturer's certification in the course of any enforcement action. In response to manufacturers' requests for interpretations of the FMVSS's, we try, to the extent possible, to provide information that will help them make their determinations of compliance. However, these responses are based on information provided by the manufacturer, and is subject to the findings of actual compliance testing by the agency. Should the agency, in the future, examine production units of these models and detect an apparent noncompliance or defect, those results will control. You first inquire, 'Please advise as to compression deflection,' which we understand as asking whether S5.2.3.2 would permit you to secure the foam with the pins. S5.2.3.2 states that each system surface, except for protrusions that comply with S5.2.4, which is contactable by a dummy head must be covered with slow recovery, energy absorbing material with specified characteristics. As explained in the next paragraph, the pins we examined appear to satisfy S5.2.4. Further, the pins might not be contactable by the dummy head in Standard 213's dynamic test. However, whether they are contactable can only be determined in the standard's dynamic test. S5.2.4 requires that any portion of a rigid structural component within or underlying a contactable surface, or any portion of a child restraint system surface that is subject to S5.2.3 shall meet specified limits on height and radius of exposed edge. Based on our visual inspection, the pins we saw appear to be within those limits. Again, however, the Vehicle Safety Act places the responsibility for determining compliance in the first instance on you, the manufacturer of the child restraint. We still have the three seats that you sent us. We plan to dispose of them unless we hear from you. I hope this information is helpful to you. Should you have any further questions or need further information, please feel free to contact Walter Myers of this office at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2117OpenHonorable Jamie L. Whitten, House of Representatives, Washington, D.C. 20515; Honorable Jamie L. Whitten House of Representatives Washington D.C. 20515; Dear Mr. Whitten: This is in further reply to your letter of October 3, 1975, for Mr Charles Russel of WJLJ, regarding tire failures on ambulances in Tupelo, Mississippi.; Pursuant to the National Traffic and Motor Vehicle Safety Act of 1966 the Department's National Highway Traffic Safety Administration (NHTSA) has issued Federal Motor Vehicle Safety Standard No.109, 49 CFR 571.109, which specifies performance and labeling requirements for new tires for use on passenger cars. Among the labeling requirements is that such tires must have their load ratings molded into or onto both sidewalls. Standard No. 119, 40 CFR 571.119, establishes similar requirements for new tires for use on trucks, buses, trailers, motorcycles, and multipurpose passenger vehicles (MPV's). The choice of standard applicable to a given tire depends on that tire's primary intended use. These standards apply to tires, and not to vehicles.; To ensure that new vehicles are equipped with proper tires, the NHTS has also issued Standard No. 110 for passenger cars and a proposed new Standard No. 120 that would apply to vehicles other than passenger cars. Briefly, Standard No. 110 requires each new passenger car to be equipped with tires which meet Standard No. 109 and which are of sufficient load carrying capacity, as evidenced by the load ratings found on the sidewalls. As proposed, Standard No. 120 would require MPV's (including ambulances) to be equipped with tires which meet either Standard No. 109 or No. 119, and which are of sufficient load carrying capacity. In the case of Standard 119 tires, sufficiency of load carrying capacity would be calculated directly from the tires' load ratings. In the case of Standard 109 (passenger car) tires mounted on an MPV, sufficiency would be determined by dividing the tire load ratings by a 110 percent correction factor before comparing these ratings with the vehicle's weight ratings. The use of passenger car tires on new ambulances would thus not be prohibited by the new standard, provided this load rating correction factor is applied. This provision would recognize an established practice which has not been found to present a safety hazard. Passenger car tires generally provide a softer, more comfortable ride than truck tires, because the latter operate at higher inflation pressures, and thus may even more desirable on ambulances, provided they are of adequate load carrying capacity. The NHTSA expects to issue Standard No. 120 in the near future.; For your convenience, I am enclosing copies of Standards Nos. 109, 110 119, and the proposed Standard No. 120.; Sincerely, William T. Coleman, Jr. |
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ID: aiam4610OpenAIR MAIL; AIR MAIL; "Mr. R. Yamauchi Seat Belt Engineering Department Nippon Seiko K.K. 12 Kirihara-cho Fujisawa, JAPAN Dear Mr. Yamauchi: This responds to your letter asking for an interpretation of Standard No. 209, Seat Belt Assemblies (49 CFR /571.209). I regret the delay in responding. Your questions concerned a seat belt assembly that is designed with a dual mode retractor. The retractor for this system generally functions as an emergency locking retractor (ELR). However, the retractor can be converted to an automatic locking retractor (ALR) to facilitate securing a child restraint at that seating position. The retractor converts from an ELR to an ALR when the webbing is completely extended. The retractor converts back to an ELR when most of the webbing has been retracted. You posed the following questions. 1. Is this retractor considered an ELR? If so, is it required to comply with the performance requirements for ELR's, or is it required to comply with the performance requirements for both ELR's and ALR's? Response: Your letter did not provide sufficient information to allow us to answer this question. However, in a July 3, 1984 letter to Mr. Donald Schwentker, we explained the criteria we use to determine whether a dual mode retractor such as you described is considered an ELR or an ALR for the purposes of our safety standards. To briefly restate the criteria, section S4.1(g) of Standard No. 209 specifies adjustment requirements for all seat belt assemblies. We examine the functioning of the retractor during normal operation by occupants within the weights and dimensions set forth in S4.1(g)(3) of Standard No. 209. If 100 percent extension of the webbing is likely to occur during normal operation of the belt assembly by those occupants (thereby converting the retractor into an ALR), the retractor would be considered an ALR. If during normal operation of the belt assembly by the specified occupants the retractor would function exclusively as an ELR, the retractor would be considered an ELR. Using these criteria, the length of the webbing used in the belt assembly will ultimately determine whether a dual mode retractor would be considered an ELR. If the webbing is long enough that a 95th percentile adult male would not extend the webbing 100 percent during normal operations (including fastening and unfastening the belt or leaning forward to adjust the radio or other controls on the instrument panel), the retractor would operate exclusively as an ELR and would be treated as such for the purposes of our safety standards. If, on the other hand, normal operations by a 95th percentile adult male would result in 100 percent extension of the webbing, the retractor would be considered an ALR for the purposes of our standards. Your letter did not provide any information about the length of the webbing to be used in the belt assembly, so we cannot offer any opinion about whether the retractor for the belt assembly would be considered an ELR or an ALR. 2. You noted that section S5.2(k) of Standard No. 209 requires that ELRs be subjected to 45,000 additional cycles of webbing withdrawal and retraction between 50 and 100 percent extension. You stated if dual mode retractors were treated as ELRs, this requirement would present serious problems, since 100 percent webbing extension would convert the retractor to an ALR and the subsequent retraction to 50 percent extension would not convert the retractor back to an ELR. Hence, when the webbing returned to 50 percent extension after 100 percent extension, the retractor would be an ALR. In this mode, the retractor would lock the webbing at 50 percent extension and no further cycles would be possible. To avoid this problem, you asked if you could test the retractor by subjecting it to 45,000 additional cycles between 0 percent extension and 100 percent extension. You asserted that this testing should be permitted, because it is a more stringent test of the retractor. Response: This question may reflect a misunderstanding of the differing responsibilities imposed on a manufacturer that is certifying compliance with a safety standard and on the agency when it is testing for compliance with a safety standard. You, as a manufacturer, are not required to conduct testing before certifying that your belt assemblies comply with Standard No. 209. Instead, the National Traffic and Motor Vehicle Safety Act requires that you exercise 'due care' in making such certifications. It is up to the manufacturer in the first instance to determine what data, test results, computer simulations, engineering analyses, or other information it needs to enable it to certify that each of its products comply with all applicable safety standards. If a manufacturer chooses to conduct testing, the manufacturer is free to modify any or all parts of the test procedure specified in the standard, provided that the manufacturer can show that the results obtained using these modified test procedures are sufficient to satisfy the 'due care' standard. You have the responsibility in the first instance to decide whether the substitution of an alternative test is sufficient to establish due care in making certifications based on this modification of the standard. This determination involves assessing whether the results of the alternative test procedure are good predictors of the results of the test procedure specified in the standard. When the agency conducts its compliance testing, however, it is required to follow the compliance tests specified in the applicable standard. Thus, the agency would not substitute cycles between 0 and 100 percent extension for the cycles between 50 and 100 percent extension that are specified in Standard No. 209. If this retractor were treated as an ELR for purposes of Standard No. 209, applying the criteria set forth above in response to your first question, we would test the retractor solely as an ELR. To do this, we would disengage or disconnect the features that convert the retractor to an ALR at 100 percent webbing extension. The retractor would then be tested in accordance with the procedures set forth in S5.2(k) of Standard No. 209. I hope this information is helpful. Please let me know if you have any further questions or need additional information on this subject. Sincerely, Stephen P. Wood Acting 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.