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: aiam4502OpenMr. Michael Pomerantz 38th Floor Tower 35 E. Wacker Drive Chicago, IL 60601; Mr. Michael Pomerantz 38th Floor Tower 35 E. Wacker Drive Chicago IL 60601; Dear Mr. Pomerantz: As you requested in a May 27, 1988, telephon conversation with Ms. Fujita of my staff, I am enclosing a copy of our November 27, 1972, letter to Mr. David Humphreys concerning paragraph S4.3 of Standard No. 207, Seating Systems. Please note that a portion of our letter to Mr. Humphreys regarding seat cushion restraints has been superseded, as explained in our September 2, 1976, letter to Mr. Tokio Iinuma. Although you were concerned only with the language of S4.3 excepting seats 'having a back that is adjustable only for the comfort of its occupants,' I have enclosed a copy of our letter to Mr. Iinuma for your information. I understand that you might be contacting us with further questions on Standard No. 207. We look forward to hearing from you. Sincerely, Stephen P. Wood Assistant Chief Counsel for Rulemaking Enclosures; |
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ID: aiam1700OpenMr. Scott B. Miller, Hadco Engineering, 2000 Camfield Avenue, Los Angeles, CA 90040; Mr. Scott B. Miller Hadco Engineering 2000 Camfield Avenue Los Angeles CA 90040; Dear Mr. Miller: This responds to your November 13, 1974, question whether a combinatio vehicle which consists of an air- braked truck tractor and an electrically-braked trailer would be subject to the requirements of Standard No. 121, *Air brake systems*, effective January 1, 1975, for trailers and March 1, 1975, for trucks and buses. The electric brakes on the trailer would be actuated by a Warner Electric brake controller that is designed to be mounted in the truck's air control line to respond to air brake signals generated by the truck's service brake control.; Standard No. 121 applies to trucks, buses, and trailers equipped wit air brake systems. Therefore, the trailer which is electrically-braked is not required to comply with the standard.; It appears from the Warner literature that you enclosed that the truc tractor would be equipped with air brakes and would therefore have to comply with the standard. I would like to point out that air-braked truck tractors manufactured after March 1, 1975, must be certified to comply with the requirements of the air brake standard. If a person modifies the air brake lines on such a truck tractor before the first retail purchase by the addition of the Warner controller, that person must certify that the truck still meets the standard as modified.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0812OpenMr. James W. Callison, 1436 E. Ovid Avenue, Des Moines, IA 50316; Mr. James W. Callison 1436 E. Ovid Avenue Des Moines IA 50316; Dear Mr. Callison: This is in reply to your letter of July 7, 1972, and your note of Jul 31, asking whether the following statement may be placed on an invoice to relieve a final-stage manufacturer making the statement of his responsibilities under the Certification regulations (49 CFR Part 567):; >>>'Delivery of this unit was accepted by the undersigned with th understanding that the unit DOES NOT meet all requirements of the Nat'l. Traffic and Motor Vehicle safety Act. The undersigned assumes full responsibility for compliance.'<<<; In a conversation you had with Mike Peskoe of this office on July 31 you elaborated on your question. It appears that such a stamp might be used in either of two situations. First, a final-stage manufacturer might use the statement if he did not wish to certify the vehicle, attempting thereby to pass on the responsibility to the person to whom he delivers it, either a dealer or purchaser. In the second case, an incomplete or intermediate manufacturer has assumed the responsibility for conformity, and certification, pursuant to sections 567.5(c) or (d), and section 568.7, and the final-stage manufacturer is returning the vehicle to the party for whom he completed it, and wishes to make it clear that he is not responsible for certification.; A final-stage manufacturer whose responsibility for certification ha not been assumed by an intermediate or incomplete manufacturer cannot remove himself from this responsibility, or require another to assume it for him. The regulations require such a manufacturer to certify the completed vehicle, and his failure to do so can subject him to civil penalties and other sanctions. The use of a disclaimer such as the stamp you enclose would be of no legal effect, even if signed by the person receiving the vehicle.; In the situation where an incomplete or intermediate manufacturer ha assumed the certification responsibility, the use of such a stamp would be unnecessary. The final-stage manufacturer should obtain written assurance of that fact from the party assuming the responsibility, *before* beginning work on the vehicle. Also, the assumption of responsibility is reflected in special provisions regarding the certification label, in accordance with S 567.5(c) and (d) of the Certification regulations. It would be advisable for any statement concerning this arrangement to make reference to the applicable regulations.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2086OpenDirector, Office of Standards Enforcement; Director Office of Standards Enforcement; SUBJECT: Certification of Universal Size Motorcycle Helmets You have asked whether a universal motorcycle helmet must b permanently labelled with the DOT label to certify compliance with FMVSS No. 218. As I understand it, these helmets are readily adjustable and can be made to fit the size C headform by means of filler material supplied by the manufacturer for the purpose of allowing such adjustment. Accordingly, they are required to comply with the standard.; The requirements of the standard apply to helmets that fit headfor size C. It is my interpretation that the term 'fit' includes the case where by means of an adjusting mechanism supplied by the manufacturer for the purpose of permitting adjustment to headform size C, *inter* *alia*, the helmet can readily be made to fit headform size C. You should, in testing the helmets for compliance purposes, follow the manufacturer's suggested procedures for fitting the helmet to the size C headform and then proceed as with any other helmet. When other headforms become available, a helmet will be required to pass the requirements for all sizes that it fits.; Frank Berndt, Acting Chief Counsel |
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ID: aiam4851OpenMs. Jessie M. Flautt 4405 Lafayette Street Bellaire, TX 77401; Ms. Jessie M. Flautt 4405 Lafayette Street Bellaire TX 77401; "Dear Ms. Flautt This responds to your letter to Mr. Steve Kratzke o my staff, requesting that the National Highway Traffic Safety Administration (NHTSA) grant permission to a repair business to modify your motor vehicle. You explained that you are under five feet, two inches and legally blind in one eye. You further explained that, due to the increased size of headrests in recent years, you are unable to locate a 1991 automobile which does not have headrests which impede your field of vision. You wish to arrange to have the size of the headrests in a 1991 automobile reduced. You asked if you could obtain permission from this agency to permit this modification. I hope the following discussion explaining our regulation will be of assistance to you. I would like to begin by clarifying that there is no procedure by which persons petition for and are granted permission from NHTSA to arrange to have a motor vehicle repair business modify their motor vehicle. Repair businesses are permitted to modify vehicles without obtaining permission from NHTSA to do so, but are subject to certain regulatory limits on the type of modifications they may make. In certain limited situations, we have exercised our discretion in enforcing our regulations to provide some allowances to a repair business which cannot conform to our regulations when making modifications to accommodate the special needs of persons with disabilities. Since your situation is among those given special consideration by NHTSA, this letter should provide you with the relief you seek. Our agency is authorized to issue Federal Motor Vehicle Safety Standards (FMVSS) that set performance requirements for new motor vehicles and items of motor vehicle equipment. Manufacturers are required by the National Traffic and Motor Vehicle Safety Act (Safety Act) to certify that their products conform to our safety standards before they can be offered for sale. Manufacturers, distributors, dealers and repair businesses modifying certified vehicles are affected by 108(a)(2)(A) of the Safety Act. It prohibits those businesses from knowingly rendering inoperative any elements of design installed on a vehicle in compliance with a FMVSS. In general, 108(a)(2)(A) would require repair businesses which modify motor vehicles to ensure that they do not remove, disconnect or degrade the performance of safety equipment installed in compliance with an applicable safety standard. Violations of 108(a)(2)(A) are punishable by civil fines up to $1,000 per violation. In situations such as yours where a vehicle must be modified to accommodate the needs of a particular disability, we have been willing to consider any violation of 108(a)(2)(A) a purely technical one justified by public need. I can assure you that NHTSA would not institute enforcement proceedings against a repair business that modifies the headrest on your vehicle to accommodate your condition. We caution, however, that only necessary modifications should be made to the headrest to accommodate your condition and we urge your dealer to modify your vehicle in such a manner that would not degrade from the safety currently provided by your vehicle. Many manufacturers are currently installing headrests in vehicles which exceed the minimum dimensions required by FMVSS No. 202, Head Restraints. I urge you not to have your headrest reduced below these dimensions if it is not necessary for your field of view. If you have further questions or need some additional information in this area, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0541OpenMr. Howard E. Ballard, Ballard Manufacturing Company, 1063 E. Third Street, Pomona, CA, 91766; Mr. Howard E. Ballard Ballard Manufacturing Company 1063 E. Third Street Pomona CA 91766; Dear Mr. Ballard: This is in reply to your letter of July 17, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You raise several questions in your letter which are restated below.; >>>1. 'What is the 'grace' period after the law comes into effect. .?'; Standard No. 302 was issued on December 9, 1970, and became effectiv with respect to vehicles manufactured on or after September 1, 1972.; 2. 'Are we correct in assuming that slide-in campers and trave trailers are not affected by this law. . .?'; The Standard applies to passenger cars, multipurpose passenge vehicles, trucks, and buses. It does not apply to trailers (including 'fifth-wheel trailers') or slide-in (including 'cab over') campers.; 3. 'Does the foam in quilted plastic material need to b flame-retardant if the plastic itself (non-quilted) is already flame-proofed?'; 4. 'If the 1/4 inch foam used in quilted material is flame-proofed must a 5 inch core of foam used in a fabricated cushion be flame-proofed, also?'; The Standard provides a detailed description of the components require to meet its requirements, and of the depth of the materials in those components that are required to be tested. Generally, the answer to both of these questions is yes, material within 1/2 inch of the surface of an item is subject to the requirements.; 5. 'On recover jobs, must we replace customer's old foam wit flame-retardant foam?'; Standard No. 302 does not apply to replacement parts of aftermarke materials.; 6. 'Must the plywoods used for backs in dinettes be flame-proofed i the plastic or cloth used to upholster them is already flame-proofed?'; You should note that the Standard does not require 'flame-proofing, rather that the specimens must not burn at more than 4 inches per minute. The test specimens are determined by depth, as stated in our preceding answer, not by the nature of the material. The answer would therefore depend on whether the plywood is within 1/2 inch of the surface.<<<; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5313OpenMr. Tom Delapp Executive Coach Builders, Inc. One Executive Boulevard Springfield, MO 65802; Mr. Tom Delapp Executive Coach Builders Inc. One Executive Boulevard Springfield MO 65802; "Dear Mr. Delapp: This responds to your letter requesting a interpretation of Federal Motor Vehicle Safety Standard (FMVSS) No. 206, 'Door locks and door retention components,' as it pertains to the locking mechanism of a so-called '5th' door installed on your limousines. I apologize for the delay in responding. We conclude that the locking mechanism on the 5th door is not prohibited by Standard 206. Based on your letter and a conversation with David Elias of my office, I understand that you have replaced the extra panel on the right side of a 1993 Lincoln Town Car based limousine with a passenger door (i.e., the 5th door). The door consists completely of the original equipment manufacturer's materials and hinges. The 5th door is a supplementary door, and does not replace or effect in any way the two side rear doors with which your vehicles are normally equipped. When the 5th door is closed, its locking mechanism engages automatically, and the door cannot be opened from the inside or the outside. A solenoid locking mechanism that unlocks the 5th door is located inside the vehicle in a 'privacy panel' behind the driver's seat. For the driver to unlock the 5th door, the car must be stopped and the driver must then get out of the car and reach through a window into the area behind the driver's seat. The locking mechanism cannot be reached by the driver while seated in the driver's seat, and cannot be reached by the passengers in the rear seats. The 5th door cannot be accidentally opened, unless the locking mechanism has been actively disengaged, the door remains locked. Disengaging the locking mechanism for the 5th door allows the driver to open the door from the outside, although passengers could push the door open from the inside, as well. There are two pertinent requirements of FMVSS No. 206 to your situation. First, S4.1.3 (Door Locks) states that: Each door shall be equipped with a locking mechanism with an operating means in the interior of the vehicle. In two prior letters, to Mr. Charles Murphy on May 10, 1974, and to Mr. Gary Hackett on April 11, 1988, the agency interpreted S4.1.3 to mean that the locking mechanism must also be operable from within the vehicle. The first question to be addressed is whether the 5th door meets the requirement of S4.1.3. We believe the answer is yes, the door is equipped with a locking mechanism with an operating means in the interior of the vehicle that is operable from within the vehicle. The operating means for the locking mechanism is in the interior of the vehicle in that the locking mechanism engages automatically when the 5th door is closed. While the means to disengage the operating mechanism is not accessible to occupants in the vehicle, Standard 206 does not require the locking mechanism to be capable of being disengaged by an occupant. This is because the purpose of the standard is to minimize the chance that occupants of the vehicle will be ejected in a collision. Thus, the thrust of the standard is to ensure that occupants are retained within the vehicle, such as by requiring doors to have door locks that occupants are capable of locking. The second pertinent requirement is S4.1.3.2 (Side Rear Door Locks), which states that: ... when the locking mechanism is engaged both the outside and inside door handles or other latch release controls shall be inoperative. The 5th door appears to comply with S4.1.3.2, in that it cannot be opened from the outside or inside when the locking mechanism is engaged. In a letter to Ms. C.D. Black, dated April 10, 1987, the agency interpreted a question on child safety locks that is relevant to your situation. The child safety lock operated as a 'secondary locking system' that, when activated, rendered the inside rear door handle incapable of opening the door. (It had no effect on the outside door handle.) As we stated in that letter, our conclusion was that Standard 206 permitted the child safety lock because the standard prohibits only secondary locking systems that interfere with the engagement, but not with the disengagement, of the primary locking system. In that letter, we wrote: The answer to your question about the child locking systems is dependent on whether the systems interfere with an aspect of performance required by Standard No. 206. We have determined that the answer is no, because the requirements of... S4.1.3.2 are written in terms of what must occur when the primary system is engaged and impose no requirements regarding the effects of disengaging the system. Thus, the aspect of performance required by S4.1.3 for the interior operating means for the door locks is that it be capable only of engaging the required door locking mechanisms. The aspect of performance required by S4.1.3.2 for door locks on the rear doors is that the inside and outside door handles be inoperative when the locking mechanism is engaged. Since we have determined that... S4.1.3.2 do es not address the effects of disengaging the required door locks-- i.e., S4.1.3.2 does not require that the inside rear door handles be operative (capable of releasing the door latch) when the required locking system is disengaged--a child locking system may be provided on a vehicle if it does not negate the capability of the door lock plunger (the operating means) to engage the door locks. I hope this information has been helpful. If you have any further questions, feel free to contact Mr. Elias at the above address or by phone at (202) 366- 2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0111OpenJames E. O'Donohoe, Esq., Messrs. O'Donohoe and O'Connor, 26 North Chestnut Avenue, New Hampton, IA 50659; James E. O'Donohoe Esq. Messrs. O'Donohoe and O'Connor 26 North Chestnut Avenue New Hampton IA 50659; Dear Mr. O'Donohoe: In your letter of August 15 you ask for a copy of regulations issue under the National Traffic and Motor Vehicle Safety Act of 1966 which might apply to 'a small refuse- carrying three-wheeled vehicle' which is being designed by one of your clients.; I enclose a copy of all Federal Motor Vehicle Safety Standards whic have been issued to date. You will note in 23 C.F.R. S 255.3(b) that the definitions of 'truck' and 'motorcycle' or 'motor driven cycle' appear to apply to the vehicle you have described. In order to make a definite classification we need more information such as 'a photograph of the vehicle and a technical specification sheet.'; However, if the vehicle is classified as a 'truck', 23 C.F.R. 255.7(a) provides that the Federal Standards will not apply if its curb weight is 1,000 pounds or less. If the vehicle is classified as a 'motorcycle' or 'motor driven cycle', Federal Standard No. 108 effective January 1, 1969, will be the only Standard applicable to this category of vehicle.; If there is any further assistance I can give you I shall be happy t do so.; Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations |
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ID: aiam2439OpenMr. Pao-Yeh Hu, Manager, TYM Industries Co., Ltd., No. 2-26, Yeng Hang, Yongkang, Tainan-Hsian, Taiwan; Mr. Pao-Yeh Hu Manager TYM Industries Co. Ltd. No. 2-26 Yeng Hang Yongkang Tainan-Hsian Taiwan; Dear Mr. He: This is in reply to your letter of September 27, 1976, to the Nationa Highway Traffic Safety Administration, concerning lighting requirements for mopeds.; The headlamp must be designed to conform to SAE Standard J584 'Motorcycle and Motor Driven Cycle Headlamps,' April 1964. This Standard does not require a sealed beam headlamp, nor is a minimum wattage specified. Obtaining an AAMVA certificate is probably the best way of insuring that a State raises no obstacles to registry of your vehicle.; There is no minimum wattage for the taillamp or stop lamp. These tw lamps may be combined. There is no Federal requirement for SAE identification, however, most lamps are so identified, because of the requirements in the state of Virginia.; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam0404OpenMr. J. Wuddel, Westfalische Metall Industrie KG, Rusck and Company, 4760 Lippstadt, Postfach 604, Republic of West Germany; Mr. J. Wuddel Westfalische Metall Industrie KG Rusck and Company 4760 Lippstadt Postfach 604 Republic of West Germany; Dear Mr. Wuddel: This is in reply to your letter of July 7, 1971, to the Nationa Highway Safety Bureau (now the National Highway Traffic Safety Administration) concerning the requirements for sealed beam headlamp units.; The answers to your specific questions are as follows: >>>1. Sealed beam units must meet the photometric specifications in SA J579 at the design voltage at or below the maximum amperes specified in SAE J573.; 2. Tolerances are as follows: *Electrical power* - the maximum electrical power is the product, i watts, of the design voltage multiplied by the maximum amperes at design volts. There is no specified minimum electrical power.; *Maximum amperes* - There is no tolerance. Maximum amperes is th maximum specified in SAE J573.; *Design watts* - There is no tolerance. There is, however, a toleranc on the actual watts or electrical power as described above.; 3. & 4. The filament types and positions are illustrative of curren practice only. Any type or position may be used to meet the specifications of J579 and J573.; 5. All glass sealed beam units are not mandatory. There are n restrictions in Federal Motor Vehicle Safety Standard No. 108 or the SAE Standards on the number of pieces or the materials which are used to complete the assembled sealed beam unit as long as the specifications, including those in SAE J571, are met. Caution should be used, however, to ensure that a good and durable seal is obtained between the metal back, if used, and the other parts to optimize the useful service life of the sealed beam unit.<<<; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto 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.