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: aiam2325OpenMr. Kenneth W. Schang, Manager, Vehicle Safety and Noise, American Motors Corporation, 14250 Plymouth Road, Detroit, MI 48232; Mr. Kenneth W. Schang Manager Vehicle Safety and Noise American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Schang: This responds to your telephone request of June 17, 1976, fo confirmation that S 575.101 of Part 575, *Consumer Information*, was recently revised to specify vehicle stopping distance information based on stops that may include wheel lockup under the conditions allowed by Standard No. 105-75, *Hydraulic Brake Systems*. You note that the text of S 575.101(c)(5), and the accompanying illustration in Figure 1 of the section, describe the information provided as performance achieved 'without locking the wheels.'; Your interpretation of the requirements of S 575.101 is correct. I amending Part 575 to permit the use of stopping distance data collected in tests for Standard No. 105-75, the agency made all changes it believed necessary to provide for the use of stopping distance information gathered in connection with Standard No. 105-75 (41 FR 1066, January 6, 1976). The reference to 'without locking the wheels' should have been deleted from the text of S 575.101(c)(5) and Figure 1. A correcting amendment will be issued shortly.; The correction of an omission from the text of the first paragraph of 575.101(c) will also be made at that time. In the last sentence of that paragraph, the concluding option (as published in the *Federal Register*) should read 'under the procedures specified in paragraph (d) of this section and the conditions specified in paragraph (e) of this section.'; Sincerely, James B. Gregory, Administrator |
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ID: aiam3867OpenMr. Dennis Moore, Sierra Product, Inc., 1113 Greenville Road, Livermore, CA 94550; Mr. Dennis Moore Sierra Product Inc. 1113 Greenville Road Livermore CA 94550; Dear Mr. Moore: This is in reply to your letter of November 26, 1984, asking whether i is permissible under Motor Vehicle Safety Standard No. 108 to combine a turn signal lamp with a center high mounted stop lamp that is intended for the aftermarket as a retrofit.; As you have noted, the recent amendments to Standard No. 108 cover th center high mounted stop lamp only as an item of original equipment and do not purport to regulate the item as an aftermarket device. This means that the prohibition of paragraph S4.1.1 against combining the center high mounted stop lamp with any other lamp does not apply. The legality of such a combination, indeed, the legality of the auxiliary stop lamp itself, is determinable under the laws of any State in which a vehicle so equipped is registered and/or operated.; The sole federal restriction on use of aftermarket devices does no appear in Standard No. 108, but in the National Traffic and Motor Vehicle Safety Act. Section 108(a)(2)(A) in essence forbids a manufacturer, distributor, dealer, or motor vehicle repair business from rendering inoperative in whole or in part lighting equipment installed in accordance with Standard No. 108. The combination turn signal/center high mounted lamp would not appear to have this effect.; I hope that this is responsive to your request. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0748OpenMr. Satoshi Nishibori, Nissan Motor Co. Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Satoshi Nishibori Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letter of June 20, 1972, on the subject of th options which may be included in the unloaded vehicle weight of a passenger car under S8.1.1 of Standard 208.; The definition of 'unloaded vehicle weight' is intended to include vehicle equipped with any combination of optional items that are installed by the factory or by the dealer with the factory's authorization. The weight of equipment installed by the dealer without authorization by the manufacturer would not be includable.; To answer your question by use of your example, you must concer yourself with both factory optional air conditioning and with dealer optional air conditioning that is authorized by the factory.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2775OpenMr. Brooks, Androw Designs, 549 Roundhill, Greenwich, CT, 06830; Mr. Brooks Androw Designs 549 Roundhill Greenwich CT 06830; Dear Mr. Brooks: This responds to your January 31, 1978, telephone request askin whether Standard No. 302, *Flammability of Interior Materials*, applies to aftermarket seat covers.; Standard No. 302 is a vehicle standard. As such, it applies to ne motor vehicles prior to their first purchase for purposes other than resale. The standard does not apply to items of motor vehicle equipment, such as seat covers, which are sold to a vehicle's owner subsequent to the vehicle's first purchase.; I would note that, with regard to the installation of interio materials in motor vehicles after the first sale for purposes other than resale, no manufacturer, distributor, dealer, or repair business may knowingly render inoperative a device or element of design (such as flame retardant materials) installed in compliance with an applicable motor vehicle safety standard (15 U.S.C., S1397(a)(2)(A)). Therefore, although the materials you produce may not always be required to meet the requirements of the standard when sold in the aftermarket, there may be situations in which the materials could not be legally installed by a manufacturer, distributor, dealer, or repair business unless they were in compliance with the standard.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3534OpenThe Honorable James Abdnor, United States Senate, Washington, DC 20510; The Honorable James Abdnor United States Senate Washington DC 20510; Dear Senator Abdnor: Your February 23, 1982, letter to Secretary Lewis on behalf of Mr. Ric Johnson has been referred to this office for reply. Mr. Johnson inquired about Federal regulations applicable to a motorcycle helmet which was worn by a person involved in a fatal accident and which Mr. Johnson believes to have been manufactured in 1979.; Federal Motor Vehicle Safety Standard No. 218, *Motorcycle Helmets* (4 Code of Federal Regulations Part 571.218), establishes minimum performance requirements for most helmets. The standard's applicability to a particular helmet depends on the date of manufacture and size of that helmet. The date of manufacture should be readily ascertainable. Paragraph S5.6.1 of the standard requires that the date and month of manufacture of each helmet subject to the standard appear on a permanent label affixed to the helmet.; The question of size is more complicated. As proposed, the standard wa to have applied to all helmet sizes. Compliance was to have been determined by placing the helmet on the appropriate headform (A, B, C or D, representing head sizes from small to large) and subjecting the helmet to certain tests. As initially implemented on March 1, 1974, the standard applied only to helmets which fit size C headforms since the other headform sizes were not available. Generally speaking, these were medium size helmets. As the enclosed notice explains, >>>'...helmets that fit headform size C' should be all helmets other than those that must be tested on the other headform sizes. To determine which helmets must be tested on a particular headform size, one follows the procedures of paragraph S6.1.3 of the standard.<<<; The other headform sizes did not become available as anticipated Consequently, the standard was extended to all helmets that can be placed on size C headforms. The substitution of 'placed on' for 'fit' brought all large helmets and many small helmets within the ambit of the standard. That extension became effective May 1, 1980. Again as explained in the enclosed notice, >>>'(p)laced' is a broader term than 'fit' primarily in that the former term does not imply any upper limit on helmet size.; Only small, child-size helmets (A) would be excluded since they coul not physically be placed on the size (C) headform. As noted in the procedures discussed above, normal fitting procedures would be used to determine if a particular helmet could be placed on the size 'C' headform, without the use of undue force.<<<; Thus, if the helmet mentioned in Mr. Johnson's letter was manufacture on or after March 1, 1974, and 'fits' the size C headform, it was required to comply with the standard. Likewise, if the helmet was manufactured on or after May 1, 1980, and can be 'placed on' the size C headform, compliance was required.; We have enclosed a copy of Standard No. 218 as it originally becam effective, as well as a copy of the amendment to the standard that became effective on May 1, 1980.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1509OpenMr. Joseph L. Lackey, Sr.,Lackey, Alexander & Jackson, Suite 1882, Parkway Towers, 404 James Robertson Parkway, nashville, Tennessee 37219; Mr. Joseph L. Lackey Sr. Lackey Alexander & Jackson Suite 1882 Parkway Towers 404 James Robertson Parkway nashville Tennessee 37219; Dear Mr. Lackey: We are enclosing herewith a copy of new Federal Motor Vehicle Safet Standard No. 119, which becomes effective March 1, 1975, and a copy of a notice of proposed rulemaking regarding a new Federal standard (No. 120) which proposes requirements for tire selection and rims for motor vehicles other than passenger cars.; There are no Federal requirements regarding the tensile strength o tire bead.; We regret we cannot be of further assistance. Sincerely, E. T. Driver, Office of Crash Avoidance, Motor Vehicl Programs; |
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ID: aiam3164OpenMr. Thomas F. Brown, Executive Engineer, Mack Trucks, Inc., P.O. Box 1761, Allentown, Pennsylvania 18105; Mr. Thomas F. Brown Executive Engineer Mack Trucks Inc. P.O. Box 1761 Allentown Pennsylvania 18105; Dear Mr. Brown: I apologize for the delay in responding to your letter of June 26 1979, questioning an opinion contained in our December 12, 1978, letter to you regarding the requirements of Federal Motor Vehicles Safety Standard No. 120. Our letter stated that your company should stamp the words 'not applicable', or words of similar import, in any spaces on your certification label which are for axles not present on the vehicle to which the label is affixed. You responded that the blank spaces on the label would not be confusing, and that the likelihood of a discrepancy between the vehicle and the label is very remote.; Our letter did not address the question of the wrong label accidentall being affixed to a vehicle. Such an occurrence would mean that the vehicle would not comply with the requirements of Standard No. 120, and it could not legally be sold in the United States. Hence, any questions about a discrepancy between the information appearing on the label and the vehicle are beyond the scope of this reply.; S5.3 of Standard No. 120 requires that the labeling informatio specified in S5.3.1 - S5.3.3 appear in the format shown in the truck example following S5.3. As explained in the December 12 letter, minor variations on what is set forth in the truck example are permitted, but only is those minor variations do not change or obscure the meaning of the label. Minor variations consist of slight differences in punctuation or a substitution of words for a punctuation mark. The purpose of the labeling requirement is to clearly convey to the user of the vehicle the information specified in Standard No. 120.; Leaving blank spaces for axles which do not exist on the particula vehicle being labeled does not, upon reconsideration, change or obscure the meaning of the label. Nor is it reasonable to assume that blank spaces will confuse the average reader of the label, when those blank spaces correspond to axles not present on the vehicle. Therefore, I am hereby withdrawing the statement in our previous letter that Mack Trucks should stamp 'not applicable' or words of similar import on certification labels for axles not present on the vehicle being labeled. It would be more accurate, however, to insert these words and it would be a simple matter to do so at the same time the other variable information is applied to the label form.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1159OpenMr. R. W. Harvey, Peterbilt Motor Truck Co., 300 Toland Street, San Francisco, CA 94124; Mr. R. W. Harvey Peterbilt Motor Truck Co. 300 Toland Street San Francisco CA 94124; Dear Mr. Harvey: This is in reply to your letter of May 22, 1973, in which you state yo are a distributor of Peterbilt trucks and ask whether certain operations you perform subject you to Federal requirements. These operations are modifications to air brake systems and the installation of used bodies on new truck chassis.; A company whose business includes the installation of used bodies o new truck chassis is a manufacturer under the National Traffic and Motor Vehicle Safety Act and, as such, has certain responsibilities under the Act and regulations issued by this agency. In response to your question regarding registration, you are required pursuant to NHTSA 'Manufacturers' Identification' regulations (49 CFR Part 566) to submit to the agency information regarding the manufacturing operations of your company and the types of vehicles that it manufactures.; A manufacturer is also required, pursuant to NHTSA 'Certification regulations (49 CFR Part 567, 568) to ascertain and certify the conformity of each vehicle he manufacturers to applicable motor vehicle safety standards. Under these regulations the person who completes the vehicle (the 'final-stage manufacturer') is required to affix to the vehicle a label that contains the certification that the vehicle conforms to applicable standards, as well as other information. Our experience has been that most manufacturers who install truck bodies onto new chassis are final-stage manufacturers, who must affix this label. Persons whose manufacturing operations precede that of the final-stage manufacturer are required to provide documentation with the vehicle that indicates what steps will be necessary in order to bring the vehicle into conformity with applicable standards.; You also ask if there are requirements for the making of periodi reports. NHTSA 'Defect Reports' regulations (49 CFR S 573.5(b)) do require manufacturers to furnish the NHTSA with quarterly production figures.; The other operation you describe is the modification of vehicle ai brake systems, including changes in valves, lines, spring brakes, air tanks, etc. If you merely modify an existing air brake system, there are presently no certification or reporting requirements applicable to you. The NHTSA has just issued certification requirements for persons who alter completed vehicles, and depending on the extent of the modification you perform, these requirements may apply to you. They are effective February 1, 1974. All trucks manufactured after September 1, 1974, that are manufactured with air brakes will be required to conform to requirements specified in Federal Motor Vehicle Safety Standard No. 121. The law would not allow you to modify the air brake system of any truck manufactured on or after that date, before the sale of the truck to a purchaser for a purpose other than resale (a user), if the modification you performed would cause the vehicle to no longer comply with the standard.; I have only summarized the requirements that, based on the facts yo have provided, would be applicable to you. Your responsibilities are stated specifically in the regulations we have referred to, and you may obtain copies of these requirements as indicated on the enclosed, 'Where to Obtain Motor Vehicle Safety Standards and Regulations.'; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3471OpenMr. Jerome N. Sonosky, Mr. Mark S. McConnell, Hogan & Hartson, 815 Connecticut Avenue, Washington, DC 20006; Mr. Jerome N. Sonosky Mr. Mark S. McConnell Hogan & Hartson 815 Connecticut Avenue Washington DC 20006; Dear Messrs. Sonosky and McConnell: This is in response to your letter of December 15, 1980, in which yo petitioned the agency to withdraw its recommended definition of 'moped' and to define the vehicle commonly referred to as a 'moped' uniformly throughout the Federal motor vehicle safety standards.; Your first petition requests the withdrawal of the recommende definition of 'moped', which the agency made available as part of its series of recommendations relating to this category of vehicles.; The principal issue relates to the agency's definition of moped as category of vehicles with pedals. In your view, the pedal requirement arbitrarily discriminates against vehicles which lack pedals but are otherwise identical to the vehicles defined in the current recommendations. To evaluate your position, the agency carried out a comparison of moped performance parameters to ascertain whether quantifiable safety differences exist between vehicles with and without pedals. The results of this analysis indicated that there are no significant differences, and the agency has therefore determined that it is appropriate to amend the definition of moped in the recommendation by removing the reference to pedals. In addition, the agency notes that the Economic Commission of Europe (ECE) regulations do not require mopeds to have pedals. Thus, to adopt your proposed definition will also aid international harmonization.; Consequently, the agency will shortly issue an advisory notice to th public of the amended definition, as it appears below, and seek additional public views for a period of thirty days.; Question 1: The present definition of 'motor-driven cycle' is 'motorcycle' with a motor that produces 5 brake horsepower or less. 49 CFR S 571.3 (1979). Does this mean that a 'motor-driven cycle' must comply with all the regulations that affect motorcycles, unless it is specifically excepted?; Answer: Motor-driven cycles must comply with all regulations that appl to motorcycles unless specifically exempted. If a particular subcategory of motor- driven cycles is exempted, that subcategory of motor-driven cycles need not comply.; Question 2: Federal Motor Vehicle Safety Standard ('FMVSS') 123, 49 CF 571.123 (1979), requires that motorcycles be equipped with footrests at each seating position. If mopeds are subject to this standard, do the pedals on mopeds that are equipped with pedals satisfy the footrest requirement for the operator's seating position?; Answer: Yes. The pedals on the moped serve as footrests even when th moped is being propelled by the engine.; Question 3: FMVSS 123 also requires that motorcycle brake systems b operable either by a right foot control or by handlebar controls. If mopeds are subject to this standard, are mopeds with propulsion pedal operated brake systems in compliance?; Answer: Yes. Since such brakes are operable by the feet, they woul comply with the requirement.; Question 4: FMVSS 127, 49 CFR S 571.127 at S.3 (1979) exclude motor-driven cycles from its requirement that each motor vehicle should have a speedometer. FMVSS 123 sets marking and illumination requirements for motorcycle speedometers, 49 CFR S 571.123 at S.1, but does not exclude motor-driven cycles. If the manufacturer of a cycle that is excluded by FMVSS 127 decides voluntarily to equip its product with a speedometer, must that speedometer conform with the requirements of FMVSS 123? Must it conform with the requirements of FMVSS 127?; Answer: FMVSS 123 requires that if a motorcycle uses a speedometer that speedometer must meet all requirements of that standard. The fact FMVSS 127 requires certain vehicles to have speedometers does not affect the uniformity requirements of FMVSS 123. Therefore, the manufacturer of motor driven cycles whose maximum attainable speed in one mile is 30 miles per hour or less need not equip such cycles with a speedometer, but if it wishes to do so, the speedometer must comply with FMVSS 123.; >>>'Moped' means a motor-driven cycle whose speed attainable in 1 mil is 30 mph or less, which is equipped with a motor that produces 2 brake horsepower or less. If an internal combustion engine is used, the piston displacement shall not exceed 50 cc and the power drive system shall not require the operator to shift gears.<<<; Your second petition relates to making uniform the various definition of low-horsepower motorcycles found in the Federal motor vehicle safety standards (49 CFR Part 571).; We agree that the time is now ripe to make consistent the variou definitions which apply to mopeds, and will issue shortly a notice of proposed rulemaking to add to 49 CFR 571.3(b) the definition of 'moped' stated above. Likewise, we propose to substitute the term 'moped' for the various phrases which define this class of vehicles in 49 CFR 571.108, 49 CFR 115, and 49 CRF (sic) 571.122. In the case of 49 CFR 567.4(g), the presence of the term 'moped' in 49 CFR 571.3(b) offers sufficient authority to identify a moped on the certification label when appropriate. Since the agency has indicated that it will soon propose rescinding Standard 127, it is unnecessary at this time to propose revisions to that standard.; Along with your petitions, you have asked a number of question relating to current NHTSA regulations. The first four questions and their answers appear below. The remaining two questions, relating to the effects on State law of FMVSS 108 and 127, are being considered separately and will be answered upon our completion of an overall review of the issue of preemption under the National Highway Traffic and Motor Vehicle Safety Act.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3021OpenMr. Robert B. Kurre, Wayne Corporation, P.O. Box 1447, Industries Road, Richmond, IN 47374; Mr. Robert B. Kurre Wayne Corporation P.O. Box 1447 Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your May 18, 1979, letter asking to what extent th parallelepiped device required by Standard No. 217, *Bus Window Retention and Release*, must fit inside a school bus in order to provide the mandated 'unobstructed passage.'; The agency responded to a request similar to yours in 1976. A copy o that interpretation is included for your information. The essence of that interpretation is that while conducting the test in accordance with S5.4.2.1(a) of the standard, the parallelepiped device must, at a minimum, fit inside a bus so that the device's outside edge is flush with the lower outside edge of the bus body. If your bus complies with this interpretation of the standard, it would be in compliance.; Sincerely, Frank Berndt, 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.