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: nht95-4.71OpenTYPE: INTERPRETATION-NHTSA DATE: November 8, 1995 FROM: Linda Stroud -- Executive Officer, Used Motor Vehicle and Parts Commission, Louisiana Dept. of Economic Development TO: Walter K. Myers, -- Attorney-Advisor, Office of the Chief Counsel, NHTSA TITLE: NONE ATTACHMT: 2/15/96 letter from Samuel J. Dubbin to Linda Stroud (A44; Std. 120) TEXT: We have spoken several times in the past month regarding the sale of new trailers with used tires. I am requesting that you confirm the following information in writing to insure that I am understanding you correctly. The information you have given me regarding these sales is that a dealer shall not sell a new trailer with used tires, he can sell with either new tires or no tires. In our conversation on November 6th, I expressed the concerns of this agency and our Louisiana dealers in the compliance of this regulation. The main problem appears to exist with the manufacturer who is shipping new trailers with used tires. You infor med me that in an instance such as this, the dealer would have to remove the used tires prior to the retail sale. When the retail sale occurred, in order for the customer to remove the trailer he would have to supply his own tires or purchase tires. In addition, the dealer could not put these tires on the trailer, the customer must perform the task himself. I am also in need of answers to the following questions: 1. What is the definition of a trailer manufacturer? 2. Is a Utility Trailer included in this safety standard or does it relate only to certain size trailers? 3. Could you indicate those trailers which are governed by this regulation? 4. Is there a specific length or width that falls under this safety standard? Thank you for your cooperation and assistance in this matter and I await your immediate response. |
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ID: nht95-4.72OpenTYPE: INTERPRETATION-NHTSA DATE: November 9, 1995 FROM: Samuel J. Dubbin -- Chief Counsel, NHTSA TO: Randall Townley -- Statewide Coordinator, The University of Georgia, Cooperative Extension Service TITLE: NONE ATTACHMT: 8/8/95 letter from Randall Townley to Office of Chief Council, NHTSA (OCC 11181) TEXT: This responds to your letter of August 8, 1995. Your letter states that you are aware that side-facing bench seats are installed in some vehicles. You asked for an opinion about this issue. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHT SA does not approve or certify any vehicles or items of equipment. Instead, each manufacturer is responsible for "self-certifying" that its products meet all applicable safety standards. NHTSA has issued only one regulation that would prohibit side-facing seats. Standard No. 222, School Bus Passenger Seating and Crash Protection, requires passenger seats in school buses to be forward-facing. For all other seats in various vehicles, NHTS A's regulations neither prohibit nor require any orientation. Therefore, any orientation is permitted provided that the seat and vehicle comply with all applicable standards. I hope this information has been helpful. If you have other questions or need some additional information, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. |
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ID: nht95-4.73OpenTYPE: INTERPRETATION-NHTSA DATE: November 13, 1995 FROM: David T. Zelis -- Marketing Manager, Buyers Products Company TO: Office Of Chief Counsel -- NHTSA TITLE: NONE ATTACHMT: 12/22/95 letter from Samuel J. Dubbin to David T. Zelis (A43; Part 581) TEXT: Enclosed please find a copy of literature describing a new product from our company. The Pintle Mount Bumper basically is designed to take the place of a vehicle bumper and the receiver tube assembly on a light duty truck. Would you please send a copy of NHTSA standards that may apply to the use or manufacture of this product. Please feel free to contact me with any questions, at (216) 974-8888. Thank you for your assistance. (Literature omitted.) |
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ID: nht95-4.74OpenTYPE: INTERPRETATION-NHTSA DATE: November 13, 1995 FROM: Tommy Reeder -- Loadcraft Manufacturing Corp. TO: Dave Coleman -- NHTSA TITLE: Lights on Rear of Trailer ATTACHMT: 1/29/96 letter from Samuel J. Dubbin to Tommy Reeder (A44; Std. 108) TEXT: WE HAVE A TRAILER CURRENTLY IN PRODUCTION THAT IS CAUSING A CONCERN ITS ORIGINAL APPLICATION WAS FOR FARM IMPLEMENTS WE NOW HAVE A CUSTOMER USING IT FOR SHIPPING CONTAINERS. IT HAS A TILT DECK -- BECAUSE OF THIS, LIGHTS ON THE EXTREME END TEND TO BE CRU SHED BY ROCKS OR MUD WHEN THE TRAILER DECK IS TILTED TO WINCH SOMETHING ON THE DECK. THE FARM TRAILER USED LIGHTS MOUNTED ON THE FURTHER MOST CROSSMEMBER FACING THE REAR OF TRAILER. DO THE LIGHTS HAVE TO BE AT THE VERY END OF THE TRAILER? WE HAVE STARTED USING A DROP BAR IN ADDITION TO THE LIGHTS ON THE CROSSMEMBER TO INCREASE VISIBILITY OF THE TAIL LIGHTS IN TRAFFIC, -- IS THIS ACCEPTABLE? Drawing omitted. |
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ID: nht95-4.75OpenTYPE: INTERPRETATION-NHTSA DATE: November 13, 1995 FROM: B. Michael Korte, Esq. -- Law Firm of John B. Schwabe II TO: NHTSA TITLE: Airbag Safety ATTACHMT: 1/29/96 letter from Samuel J. Dubbin to B. Michael Korte (A44; Std. 208) TEXT: To Whom It May Concern: I am a lawyer in St. Louis, Missouri who represents a client who injured in a rearend collision with another driver. The other driver's airbag deployed, but the other driver claims that she was travelling less than 15 miles per hour at impact. I have, as best as I can, reviewed 49 CFR 571.208 and other sections of the Code of Federal Regulations regarding federal standards as to the deployment of airbags. After doing so, however, I am unable to determine whether or not any federal standard s exist as to the deployment of airbags. In other words, I am unable to determine whether or not federal regulations establish a minimum speed that vehicles must be travelling, below which an airbag will not deploy. I would appreciate it if you would contact me and let me know whether or not any such regulations or guidelines exist. Thank you for your cooperation, courtesy and attention to this request. |
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ID: nht95-4.76OpenTYPE: INTERPRETATION-NHTSA DATE: November 14, 1995 FROM: Terence J. Kann TO: Ricardo Martinez -- Administrator, NHTSA TITLE: NONE ATTACHMT: 12/22/95 letter from Samuel J. Dubbin to Terence J. Kann (A43; Std. 108) TEXT: I am writing to you concerning Standard No. 108, which amended 49 CFR Part 571 to require application of retro-reflective sheeting or reflex reflectors to provide for greater conspicuity of the sides and rear of trailers. I have the following question. Section S3, Application (a) provides that the standard applies to ". . . trailers (except pole trailers) . . .". Section S5.7 provides that "each trailer of 80 or more inches overall width and with GVWR over 10,000 pounds manufactured on or after 12/1/ 93, except a trailer designed exclusively for living or office use, shall be equipped with either retro-reflective sheeting . . . reflex reflectors . . . or a combination . . .". My question is, are pole trailers such as those used in the logging industry, required to have retro-reflective sheeting, reflex reflectors, or a combination? If not, did the NHTSA issue any explanation for failing to extend the requirements to pole t railers? If yes, could you please provide a copy? Thank you for your assistance. Please don't hesitate to call or write if you have any questions or comments regarding the above. |
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ID: nht95-4.77OpenTYPE: INTERPRETATION-NHTSA DATE: November 15, 1995 FROM: Richard L. Russell TO: Blane Laubis -- Office of Vehicle Safety Compliance, US Dept. of Transportation TITLE: NONE ATTACHMT: 12/22/95 letter from Samuel J. Dubbin to Richard L. Russell (A43; Std. 108) TEXT: I now have two DOT Approved headlights on my 1956 Jeep and I would like to add two additional Auxiliary Lights to supplement my highbeams. These lights would be wired into the highbeam switch, so that, they can only be used on highbeam and mounted on my bumper below my DOT Approved headlights (36.5" from the ground). My question is . . . are my auxiliary lights required to be DOT approved? Are they required to be SAE approved? And is there any limitation to bulb wattage for auxiliary lights used to supplement the DOT approved headlights while they are on highbeam? I understand that the State of California may have regulations to further define or restrict the use of auxiliary lights. I would appreciate your response to these questions at your earliest convenience. |
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ID: nht95-4.78OpenTYPE: INTERPRETATION-NHTSA DATE: November 16, 1995 FROM: Kenneth W. Easterling -- Plan B Engineering, Inc. TO: Taylor Vinson -- NHTSA; Samuel J. Dubbin -- Chief Counsel, NHTSA TITLE: Collision Avoidance Technology ATTACHMT: 12/22/95 letter from Samuel J. Dubbin to Kenneth Easterling (A43; Std. 108); 7/30/93 letter from John Womack to Wayne Ferguson TEXT: THANK YOU FOR TAKING TIME TO DISCUSS THE DEVELOPMENTS MADE RECENTLY OUR COLLISION AVOIDANCE DEVICE NOW IN THE FINAL DESIGN STAGES. AS PER YOUR DIRECTIVE. I HAVE ATTACHED A BRIEF SYNOPSIS OF THE SUBJECT DEVICE FOR YOUR CONSIDERATION AND OPINION. IF I CAN PROVIDE ANYTHING FURTHER IN TERMS OF PRODUCT ILLUSTRATION OR EXPLANATION, PLEASE GIVE ME A CALL. WE SINCERELY THANK YOU IN ADVANCE FOR YOUR PERSONAL COMMENTARY AND SUBMISSION TO MR. DUBBIN'S OFFICE FOR INSPECTION. VERY BEST REGARDS, KENNETH W. EASTERLING Attachment Mr. Samuel J. Dubbin Chief Counsel NHTSA, Room 5219 Subject: Rear End Collision Avoidance Re: Proportional Deceleration Indicator Lamps (aka) G-Lamps Dear Mr. Dubbin: In recognition of the significant work and contributions to highway safety, I submit for your consideration and opinion, the concept and justification for G-Lamps. To be specific, an inertial driven, proportional deceleration indicator lamp as an intended enhancement to existing single filament, on/off style incandescent brake lamps. We have recently entered final design stages on the device and initial tests h ave revealed some startling results in decreased driver reaction times when compared to the industry standard products. Building on my work experience within the California Highway Patrol, I recognized the need for motorists to be aware of not only when a vehicle ahead of you was braking, but to what degree the deceleration was be made. Tests have shown reaction times were cut in half when a motorist was visually appraised of increasing, hard braking activity instead of having to judge the rate of diminishing distance between his/her vehicle and the braking motorist (as is the case with on/off style brake lamps). In the case of freeway speeds, these reaction times and distances are accumulated from one vehicle to the next (rear) until ultimately (at freeway speeds) a rear end collision is imminent. G-Lamps was developed to provide motorists to the rear, visual reference to the degree of braking activity on a real-time basis. Valuable distance is directly proportionate to time lost in reacting to sudden stops or increasingly harder braking. As we all know, there exists a tendency to "ride" our brakes when anticipating slow-downs or stops. This has effectively eliminated the benefits of standard brake lamps. From the time of activation, the degree of braking activity is anyone's guess. To mo torists to the rear it may very well end up in excessive vehicle damage and injury liabilities. For your inspection, explanation of the device is delivered on the following pages. I have tried to be as informative as possible without laboring you with manufacturing details that would rival a sales pitch. I thank you in advance for your input and contributions to this effort. Kenneth Easterling, President, Plan B Engineering Inc. Intent and Purpose The device was conceived to counter the hazards of hard braking while in traffic at highway speeds. It is intended to enhance existing brake indicator lamp systems and not to deviate from customary and expected visual queues during motor vehicle oper ation with one important exception. Specifically, braking activity in excess of normal deceleration (defined as an appreciable decay of forward momentum of the vehicle) would activate decelerometer circuitry housed within the lamp bulb itself and be viewed from the rear as proportionate ly faster flashing light equating to the degree of deceleration. Normal braking would display customary visual queues as a steady burn of the brake lamp. It is well established through independent studies and government testing, driver reaction times are severely compromised as the distance between vehicles decrease under various breaking conditions. This scenario is aggravated by the need to visually judge the rate of deceleration of the stopping vehicle and a following driver to respond accordingly. The device proposed will deliver visual feed-back to following motorists of greater than normal braking activity. The ergonomics of the device are geared to normal reflex actions of potential and proportion. The greater the rate of deceleration of t he vehicle the faster the cycles per second of the inertial lamp. Therefore, the following vehicle's response will be to react with potentially greater braking activity much sooner than normal. Thus capturing valuable stopping distance that would other wise be lost. This problem is further exaggerated by less than desirable visual acuity present in more than three quarters of the motoring public. Abstract of Device (i.e. form, fit and function) While the form and fit of the device mimic the present day designs for incandescent, filament style lamps, the similarity must end there. Unlike it's predecessor, the inertia lamp is mechanically dynamic in function. To operate the device must be sub jected to substantial negative G-forces which can only be generated by the sudden and rapid deceleration the vehicle in which it is mounted. Without these influences, the bulb assembly acts as any other lamp bulb, in terms of constant steady burn associ ated with normal deceleration rate, when the brake system is activated. By nature of design, the inertia bulb will activate in concert with the steady burning "normal" brake lamp. Once energized, the inertia flash filament portion of the lamp will increase the flash rate by cycles per second (Hz) proportionate to the rat e of declaration. This is a desired means of attaining a quantification of braking magnitude. Microelectronics technology allows the timing circuitry to be housed within a standard "bayonet" style socket with no modification to the manufacturer's electrical or molded lens structures. State of the art manufacturing techniques allow the device to be fabricated in cost ranges considered to be competitive with existing high performance lamps. The solid state design and minimal parts involved insure long life and serviceability. Summary In conclusion, our studies indicate this device to be the most straight forward, technically viable and ergonomically effective means of reducing the single most prolific cause of vehicular collisions today, "the rear-ender". Billions of dollars annua lly are paid out by insurance companies for damages and bodily injury claims directly related to these types of collisions. Considering the enormous loss in work time, productivity in the economy and personal pain and suffering, the numbers are staggeri ng. Recently a precedence was set by General Motors with the introduction of the Daytime Running Lamp. Recognizing a simple but highly effective means of vehicular illumination, a major, profit oriented corporation was willing to make a billion dollar in vestment to highway safety. The motoring public as well as the companies that insure their financial responsibility, have come to expect a product that is as safe as technically and morally possible. |
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ID: nht95-4.79OpenTYPE: INTERPRETATION-NHTSA DATE: November 16, 1995 FROM: Dietmar K. Haenchen -- Manager, Vehicle Regulations, Volkswagen of America, Inc. TO: Chief Counsel -- NHTSA TITLE: Request for Interpretation, FMVSS 124 "Accelerator Control Systems" ATTACHMT: 1/19/96 letter from Samuel J. Dubbin to Dietmar K. Haenchen (A44; Std. 124) TEXT: This letter is to request an interpretation with regard to the provisions of Section S5.1 which requires "at least two sources of energy capable of returning the throttle to the idle position within the time limits specified by S5.3 . . . In the event of failure of one source of energy by single severance or disconnection, the throttle shall return to the idle position within the time limit specified by S5.3 . . ." The specific question for interpretation relates to the compliance under S5.1 of a system using a coil spring composed of multiple strands of wire twisted into a wire cable which is then coiled into a spring. This would provide "at least two sources of energy" because the individual strands that compose the wire cable each provide a separate source of energy. A drawing of such a spring showing a cable of three strands of wire is attached. Also enclosed is a sample spring which uses seven strands of w ire. Assuming in the spring consisting of three strands of wire, that if only one strand is broken, the remaining two would have sufficient force to return the throttle to idle, we believe such a spring would comply with S5.1 of the Standard. The seven strand wire spring provides even greater redundancy if, for example, the spring would have sufficient force to return the throttle to idle if up to three of the wire strands were broken. Endurance testing on seven strand wire springs without damage and with intentional damage has shown that even if damaged by the separation of one or two wire strands, the coil spring is still fully functional with enough torque to perform its intended function. For purposes of this request for interpretation, it should be assumed that only a single coil spring consisting of the multiple strands would be provided to close the throttle. Your response as soon as possible (within 30 days) will be appreciated. Drawing omitted. |
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ID: nht95-4.8OpenTYPE: INTERPRETATION-NHTSA DATE: August 30, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: William Meurer -- President, Green Motorworks TITLE: NONE ATTACHMT: ATTACHED TO 8/9/95 LETTER FROM WILLIAM MEURER TO JOHN WOMACK TEXT: Dear Mr. Meurer: This is in reply to your letter of August 9, 1995, responding to mine of July 14. We note that you have withdrawn the application by PIVCO AS for temporary exemption from the automatic restraint requirements of Motor Vehicle Safety Standard No. 208, and have enclosed PIVCO AS's designation of you as its agent for service of process. You have talked with Taylor Vinson of this office about your wish to import 12 City Bee electric vehicles manufactured by PIVCO AS, pursuant to 49 CFR 591.5(j). Although requests for permission to import a vehicle under section 591.5(j) are normally mad e to the Director, Office of Vehicle Safety Compliance, Mr. Vinson advised you to address your letter to this office because you seek a waiver from a restriction on such importations set out in 49 CFR 591.7(c). 49 U.S.C. 30112(a) prohibits, among other things, the importation of any motor vehicle that does not comply, and is not certified as complying, with all applicable Federal motor vehicle safety standards. However, section 30114 (formerly 15 U.S.C. 1397(j )) provides that the agency may exempt a nonconforming vehicle from section 30112(a) on terms that the agency "decides are necessary for research, investigation, demonstrations, training, or competitive racing events." Pursuant to 49 CFR 591.5(j), an imp orter such as Green Motorworks, which is not a manufacturer of a motor vehicle certified as meeting all applicable Federal motor vehicle safety standards, may import a nonconforming vehicle for the purposes enumerated in section 30114 if the importer has received written permission from the National Highway Traffic Safety Administration (NHTSA). We are construing your letter as a request pursuant to 49 CFR 591.5(j). Under section 591.6(f)(1), such a request must contain "a full and complete statement identifying the vehicle . . . its make, model, model year or date of manufacture, VIN if a motor vehicle, and the specific purpose(s) of importation." The discussion of purpose must include a description of the use to be made of the vehicle, and, if use of the public roads is an integral part of the purpose for which the vehicle is imported, the statement shall request permission for use on the public roads, describing the use to which the vehicle shall be put, and the estimated period of time during which on-road use is necessary. Finally, the statement shall include the intended means of disposition (and disposition date) of the vehicle after completion of the purp ose for which it was imported. The Statement of Work that you enclosed indicates that the 12 noncomplying City Bees will be used in a Bay Area Station Car Demonstration Project that terminates September 15, 1997, the purpose of which is to determine the usefulness of electric cars for everyday short trips made by Bay Area Rapid Transit (BART) patrons who commute to work (28 additional cars to be provided in 1996 are to comply fully with the Federal motor vehicle safety standards). The project is financed by the Bay Area Quality Mana gement District, the Advance Projects Research Administration of the U.S. Department of Defense, Pacific Gas & Electric Company, California Energy Commission, and California Department of Transportation. You have stated that the cars will be exported or destroyed at the end of the demonstration project. Your statement is sufficiently complete that we can grant conditional permission at this point; when you provide the Office of Vehicle Safety Compliance with the information that is lacking, that office will provide you with the final permission necessar y to importation. Specifically, you have not provided the model year or date of manufacture of the City Bees that will be imported, nor their VINs. Under paragraph 591.7(c), the importer must "at all times retain title to and possession of" vehicles imported pursuant to section 591.5(j)(2)(i), and "shall not lease" them. You seek a waiver of this restriction because you intend to lease the City Bee s to BART for the duration of the demonstration project. I find that, under the general authority of section 30114, the agency may provide Green Motorworks with a waiver from the limitation set out in paragraph 591.7(c). First of all, section 30114 imposes no limitations on the agency's exemption authority. It simply provides NHTSA with the discretion to permit the importation of noncomplying vehicles for certain purposes "on terms [NHTSA] decides are necessary." Second, the restriction on possession, control, and leasing set out in paragraph 591.7(c) is no t required by statute. It arose from the agency's effort to forestall attempts at subterfuge by importers. The Statement of Work makes clear that the data derived from research, investigations, and demonstrations utilizing the 12 City Bees is sought and supported by several Regional, Federal, and State governmental agencies and a public utility and that the p roposed lease to BART will facilitate the project. Finally we note that the City Bees will apparently meet all applicable Federal motor vehicle safety standards with the exception of the automatic restraint requirements of Standard No. 208. Therefore, N HTSA believes that waiving paragraph 591.7(c) in this instance will be in the public interest. If you have any further questions, you may again consult with Taylor Vinson on this matter at (202) 366-5263. |
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.