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 |
|---|---|
ID: GF002300OpenMr. Paul Pridemore Dear Mr. Pridmore: This responds to your letter of March 14 and phone conversations with George Feygin of my staff, regarding your Model 7000 trailer. You asked us whether your trailer qualifies as a "special purpose vehicle" under Federal Motor Vehicle Safety Standard (FMVSS) No. 224, Rear Impact Protection. You also asked whether a "tilting rear guard," photographs of which you have enclosed, would satisfy the requirements of FMVSS No. 224, as well as FMVSS No. 223, Rear Impact Guards. I apologize for the delay in responding. The issues raised by your letter and phone conversations are addressed below. By way of background, the National Highway Traffic Safety Administration (NHTSA) administers Federal requirements for the manufacture and sale of new motor vehicles and certain items of motor vehicle equipment. NHTSA issues FMVSS applicable to new vehicles and equipment. Chapter 301 of Title 49 of the United States Code, "Motor Vehicle Safety" (49 U.S.C. 30101 et seq.), establishes a certification process under which each manufacturer is responsible for certifying that its products meet all applicable FMVSS. In an attempt to reduce the frequency and severity of underride collisions, NHTSA issued FMVSS No. 224 (61 FR 2004, January 24, 1996). The standard requires that all new trailers and semitrailers with a gross vehicle weight rating of 10,000 lbs or more be equipped with an underride guard that meets the requirements of FMVSS No. 223. The standard currently excludes pole trailers, pulpwood trailers, wheels-back trailers, and "special purpose vehicles" because attachment of an underride guard to these specific vehicles is impracticable or unnecessary. A "Special Purpose Vehicle" is defined in S4 of FMVSS No. 224 as a trailer or a semitrailer having work-performing equipment that, while the vehicle is in transit, resides in, or moves through the area that could be occupied by the horizontal member of the rear underride guard. Your "tilting rear guard," which acts as an approach ramp when the trailer is tilted down, is the only part of your trailer that, while the vehicle is in transit, resides in the area that could be occupied by a conventional the rear impact guard. Therefore, this "tilting rear guard" would have to be considered work-performing equipment for your tilt bed trailer to be excluded. Your vehicle does not meet the definition of a special purpose vehicle. There is no definition of "work-performing equipment" in Standard No. 224. However, the Agency has historically interpreted the words "work-performing" to mean that the equipment must actively perform its function, and that the function must involve exerting force or moving something else. Approach ramps do not perform work in this sense because they merely form a ramp between the ground and the vehicle or equipment driving onto the tilt bed. Therefore, a "tilting rear guard" that acts as an approach ramp is not work-performing equipment, and your trailer does not meet the definition of a special purpose vehicle. In regard to your second question, we note that the static dimensions of your "tilting rear guard" (as described in your letter and accompanying photographs) appear to satisfy the requirements of FMVSS Nos. 223 & 224. Specifically, the guard appears to extend to within 100 mm of the side extremities of the trailer, thus satisfying the width requirement of S5.1.1; the bottom edge of the guard is said to be within 382 mm of the ground, thus satisfying height requirements of S5.1.2; and the guard appears to be on the very edge of the trailer, thus satisfying rear surface requirements of S5.1.3. However, FMVSS No. 223 contains guard strength and energy absorption requirements found in S5.2.1 and S5.2.2 respectively. You have provided no information as to whether the "tilting rear guard" is able to meet the performance requirements of S5.2.1 and S5.2.2. Accordingly, we are not in position to determine whether the "tilting rear guard" is in compliance with FMVSS Nos. 223 & 224. I hope this information is helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosure |
2003 |
ID: GF002470OpenTed Gaston, Director of Maintenance Dear Mr. Gaston: This responds to your recent e-mail asking whether Federal Motor Vehicle Safety Standard (FMVSS) No. 108,Lamps, Reflective Devices and Associated Equipment, permits a hazard warning flasher system that actuates automatically each time a transit bus stops to pick up and discharge passengers. Our answer is no. By way of background, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. In your e-mail, you describe a hazard warning flasher system which would automatically actuate each time the following criteria are met: (1) the bus is in gear, (2) brakes are applied, (3) the bus speed is below 3 mph, and (4) the front door is opened. Table I of FMVSS No. 108 requires motor vehicles, including transit buses, to be equipped with hazard warning signal systems, as specified in SAE Recommended Practice J910, February 1966. Paragraph 1 of SAE J910 defines such system, in part, as "a driver controlled device which causes all turn signal lamps to flash simultaneously". We have previously interpreted "driver controlled" to mean that the hazard warning signal system must be activated and deactivated by the driver and not by automatic means (please see attached letters to Paul Michelotti, Eric Reed, and Mark Steele). Accordingly, the system being contemplated by Muncie Indiana Transit System would be prohibited by FMVSS No. 108. I hope you find this information helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman ref:108 |
2005 |
ID: GF002551.3OpenMr. Robert M. Clarke Dear Mr. Clarke: This responds to your March 11, 2005, letter regarding installation of certain auxiliary lighting on heavy-duty trucks and truck tractors. Specifically, you ask about installing auxiliary lamps in the vicinity of the front identification and clearance lamps. You also ask about installing auxiliary lamps above or below the surface occupied by front identification and clearance lamps. The standard relevant to your question is Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, reflective devices and associated equipment. For vehicles of 80 or more inches in overall width (such as the trucks and the truck tractors described in your letter), Table II of FMVSS No. 108 requires that 3 amber identification lamps (three-lamp cluster) be located as close as practicable to the top center of the vehicle or the cab, with lamps placed 6 to 12 inches apart. The function of this three-lamp cluster is to indicate the presence of a large vehicle on the roadway. Table II also, requires that two amber clearance lamps be located "to indicate the overall width of the vehicle . . . and as near the top thereof as practicable." Before addressing the auxiliary lamp configurations discussed in your letter, we note that S5.1.3 of FMVSS No. 108 prohibits installation of lamps that would impair the effectiveness of the required lighting, including the identification lamp cluster. The agency has long maintained that highway traffic safety is enhanced by the familiarity of drivers with established lighting schemes, which facilitates their ability to instantly recognize the meaning the lamps convey and respond accordingly. Therefore, the agency previously explained that auxiliary lamps must be located such that they would not interfere or be confused with the lamps required by our standards. For example, in a January 21, 2004, interpretation letter to a confidential party, the agency explained that auxiliary lamps must be located far enough away from the three-lamp cluster, so that they do not impair their effectiveness. In an October 18, 2002, letter to Mr. Weidman, we indicated that two auxiliary lamps located next to the three-lamp cluster would detract from the purpose of the cluster. With this background in mind, we turn to auxiliary lamp configurations described in your letter. You provided descriptions and illustrations showing several different lamp configurations and asked whether these configurations would be permitted under FMVSS No. 108. Specifically, you describe three configurations consisting of the three-lamp identification cluster, two clearance lamps, and one or more sets of auxiliary lamps located between the clearance lamps and the three-lamp cluster. You ask if all three configurations would comply with FMVSS No. 108. In alternative, you ask that the agency confirm that the auxiliary lamps are permissible, if the distance between the three-lamp cluster and the auxiliary lamps is at least twice the distance that separates each lamp in the cluster. First, we note that auxiliary lamps located immediately adjacent to the three-lamp cluster would not be permitted by FMVSS No. 108 because they would impair the effectiveness of identification lamps. The purpose of the three-lamp cluster requirement is to signal the presence of a large vehicle to other drivers. The number of lamps, three, is a part of the signal, and additional lamps could make the signal less recognizable. Second, while we would generally prefer to establish distance requirements through rulemaking, we recognize the need for guidance with respect to the permissible positioning of auxiliary lamps located between the clearance lamps and the three-lamp cluster. We believe that positioning auxiliary lamps at a distance that is at least twice the distance that separates each lamp in the required three-lamp cluster provides sufficient separation not to impair the effectiveness of the three-lamp cluster (see diagram below). Third, you also asked about installing auxiliary lamps above or below the surface occupied by the three-lamp cluster and the clearance lamps. We note that FMVSS No. 108 does not prohibit auxiliary lamps that are located on a different surface from the three-lamp cluster and the clearance lamps. Specifically, auxiliary lamps may be located on the roof of the truck cab, if the required lamps are located on the sleeper roof above the cab roof. The reverse arrangement is also permissible. In either configuration, the auxiliary lamps are located at a sufficient distance from the required lamps that they would not impair their effectiveness. Finally, we note that the auxiliary lamps must have the same photometric output and be of the same color as the lamps specified in Table II to avoid impairment. We believe that maintaining color and photometric output consistency is important because, for example, the presence of red auxiliary lamps located next to amber clearance lamps could confuse drivers as to the traveling direction of the vehicle. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman ref:108 |
2005 |
ID: GF002565OpenTony Dosmann, President Dear Mr. Dosmann: This responds to your letter in which you requested an interpretation of certain requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 110, Tire Selection and Rims and 49 CFR Part 567, Certification. Both regulations require permanently affixed labels. You ask us to explain the meaning of "permanent". In previous letters of interpretation, we have explained that specifying precisely how a label is to be affixed could be design restrictive. However, when the agency requires a permanently affixed label for a vehicle, the label must be affixed in a manner that would make it likely to stay attached and legible during the lifetime of the vehicle, under normal conditions. We have previously stated that a label affixed to the vehicle using adhesives would be considered adequate. Finally, in previous letters we cautioned that labels should not be attached in a manner where they can be easily detached. I have enclosed copies of several relevant letters. I hope you find this information helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosure |
2005 |
ID: GF002595Open
Ms. Nancy Liu Dear Ms. Liu: This responds to your e-mail to George Feygin of my staff regarding the labeling requirements for brake hoses and brake hose assemblies found in S5.2.2(b) and S5.2.4(b) of Federal Motor Vehicle Safety Standard (FMVSS) No. 106; Brake Hoses. Specifically you state that you have filed a manufacturers designation "SUNSUNG" with the National Highway Traffic Safety Administration (NHTSA), as required by S5.2.2(b). You ask whether you may use the same designation to label brake hose assemblies as required by S5.2.4(b). Additionally, you ask whether a manufacturer needs to provide samples for agency testing. The issues raised by your letter are addressed below. By way of background, NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. Accordingly, a manufacturer need not provide the agency with brake hose samples for testing. Instead, the manufacturer is responsible for self-certifying its product. If the agency decides to test the brake hose or brake hose assemblies manufactured by your company, the agency will purchase samples of your product on the open market. With respect to brake hose and brake hose assembly labeling, we note that S5.2.2(b) requires that each manufacturer mark the brake hose with, among other things, a designation filed with NHTSA. Similarly, S5.2.4(b) also requires that each manufacturer mark the brake hose assembly with, among other things, a designation filed with NHTSA. A manufacturer can use the same designation for both sets of requirements. Because you already filed a manufacturers designation "SUNSUNG" under S5.2.2(b), you need not file a separate designation under S5.2.4(b). In addition, I would like to direct your attention to the following two requirements:
For your reference, I also enclose an information package for new equipment manufacturers. I hope this information is helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosures |
2004 |
ID: GF002676OpenMr. Dale W. Soos Dear Mr. Soos: This responds to your e-mail of April 17 asking about the length of hose specimens required for certification under Standard No. 106, Brake Hoses. In your e-mail, you state that your client intends to manufacture a single brake hose product line that would feature length variation, so that individual brake hoses can properly fit custom-built trailers. You ask whether a single hose length can be used to certify an entire product line. The issues raised by your letter are addressed below. By way of background, the National Highway Traffic Safety Administration (NHTSA) administers Federal requirements applicable to the manufacture and sale of new motor vehicles and certain items of motor vehicle equipment, including brake hoses. NHTSA issues Federal motor vehicle safety standards applicable to new vehicles and equipment. Chapter 301 of Title 49 of the United States Code, "Motor Vehicle Safety" (49 U.S.C. 30101 et seq.), establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable Federal motor vehicle safety standards. NHTSA tests vehicles and equipment for compliance with the Federal motor vehicle safety standards and investigates defects relating to motor vehicle safety. If a manufacturer or NHTSA determines that a noncompliance or safety-related defect exists, the manufacturer must notify purchasers of its product and remedy the problem free of charge. In certain circumstances, a manufacturer of a noncomplying product may also face a civil penalty of up to $5,000 for each noncomplying item it produces. Standard No. 106 applies to "brake hoses" (which include plastic tubing), brake hose end fittings, and brake hose assemblies. The standard specifies labeling and performance requirements for these products to reduce the likelihood of brake system failure from ruptures in the brake hose or brake hose assembly. New brake hoses, end fittings, and assemblies must meet these requirements to be sold in or imported into this country. As previously stated, NHTSA relies on self-certification process where each manufacturer certifies its product. Accordingly, we are not in position to determine whether it would be prudent for you to use a single hose length to certify the entire product line. A manufacturer is responsible for determining the testing and analysis necessary for certification. We note that in carrying out the self-certification, each manufacturer is expected to exercise due care and sound engineering judgment. If later asked to do so by the agency, a manufacturer would have to be able to show it was reasonable to believe that a shorter hose lengths meeting the specified performance requirements accurately predicted the performance of a longer hose length, or vice versa, since all hoses must comply with the performance requirements specified by the standard. Thus, NHTSA cannot comment on whether there is any appropriate representative hose length. I hope this information is helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman ref:106 |
2003 |
ID: GF002714OpenMr. Mike Chuppe PO Box 253 7248 Highway 18 Hoople, ND 58243 Dear Mr. Chuppe: This responds to your letter asking whether your vehicles are subject to the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 224, Rear impact protection. Specifically, you ask if straight trucks are subject to the requirements of FMVSS No. 224. Within the context of your letter we understand straight trucks to mean heavy vehicles designed to transport goods under their own motive power as opposed to being drawn by another motor vehicle. Along with your letter, you provided pictures of the vehicles in question. However, the pictures depicted only the rear portions of each vehicle, and we could not confirm whether the pictures were of straight trucks or trailers. In relevant part, S4 of FMVSS No. 224 reads as follows: S3. Application. This standard applies to trailers and semitrailers with a GVWR of 4,356 kg or more. 49 CFR 571.3 defines a trailer as a motor vehicle with or without motive power, designed for carrying persons or property and for being drawn by another motor vehicle. The same section also defines a semitrailer as a trailer, except a pole trailer, so constructed that a substantial part of its weight rests upon or is carried by another motor vehicle. Unless your vehicles fall under one of the two definitions, they are not subject to the requirements of FMVSS No. 224. You also asked whether straight trucks would fall under paragraph (b) of Federal Motor Carrier Safety Administration (FMCSA) Regulation 393.86. We have consulted with Mr. Michael Huntley, Chief, Vehicle and Roadside Operations Division, Office of Bus and Truck Standards and Operations, at FMCSA, who has confirmed that FMCSA Regulation 339.86(b) applies to straight trucks. If you need further assistance, please contact J. Edward Glancy of my staff at this address or at (202) 366-2992. Sincerely, Anthony M. Cooke Chief Counsel ref:224 d.8/11/06 |
2006 |
ID: GF003064OpenMr. Christopher H. Willison Dear Mr. Willison: This responds to your letter of April 1, 2004, and subsequent conversations with George Feygin of my staff. You ask a series of questions regarding DOT regulations related to a pressure vessel used for tire inflation located inside a hollow semi-trailer axle. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards (FMVSSs) that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements. There is no FMVSS regulating pressure vessels located in hollow semi-trailer axles as described in your letter. In fact, the agency does not have any regulations covering tire inflation systems for heavy vehicles. However, if your system is tied into the vehicles air braking system, it may affect compliance with other safety standards. Specifically, FMVSS No. 121, Air Brake Systems, may have implications for your product, especially if your device is an integral part of the brake system. We do not have sufficient information about your device to discuss FMVSS No. 121 implications. However, in a previous letter of interpretation (copy attached) we stated that a tire inflation device would not be considered a part of the braking system if it was separated from the vehicles main braking system by a pressure protection valve in such a way that the main braking system would not be affected by a leakage failure in the device. Further, the air supply line between the air supply tank described in your letter and the pressure vessel could be considered a brake hose subject to the requirements of FMVSS No. 106, Brake Hoses. In a previous letter of interpretation, we stated that if a failure of a hose or a supply line would result in a loss of pressure in the brake system, that hose or supply line are subject to the requirements of FMVSS No. 106 (copy enclosed). For your reference, I am enclosing a fact sheet we prepared entitled Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment. I hope this information is helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosures |
2004 |
ID: GF003147OpenKenneth M. Bush, Associate Director Dear Mr. Bush: This responds to your letter in which you ask about the procedures the National Highway Traffic Safety Administration (NHTSA) would follow for locating "Point 1" described in S10.1(a) of Federal Motor Vehicle Safety Standard (FMVSS) No. 201, Occupant protection in interior impact. You provide an illustration and two different interpretations of these procedures. By way of background, FMVSS No. 201 requires that vehicles meet certain performance criteria when specific targets in the interior are struck by an instrumented headform representative of a human head. When NHTSA performs compliance testing, it does so in accordance with testing procedures specified in FMVSS No. 201. With respect to targets located on the A-pillar, the agency would perform testing using the target location procedure in S10.1. In order to locate "Point 1" described in your letter, the agency would follow the following procedure described in S10.1(a):
NHTSA locates "Point 1" by measuring inboard, along the nominal vehicle exterior surface, 125 mm from the intersection of "Line 1" and the outermost edge of the roof, with the door open. "Line 1" is established by locating a transverse vertical plane (Plane 1) that is perpendicular to the vehicle longitudinal plane, which contacts the rearmost point of the windshield trim. We note that the outermost edge of the roof is determined with the door open and includes uncompressed weather stripping, rain gutter, or other trim components. NHTSA makes linear measurements following the nominal vehicle surface (as opposed to following each convolution of weather stripping, rain gutter or other trim components). See Laboratory Test Procedure for FMVSS No. 201U (TP-201U-01, April 3, 1998, pages 37 and 38 at www.nhtsa.gov), and the enclosed illustration. In your letter and accompanying illustration, you offer two interpretations for the location of "Point 1." The difference between the two interpretations appears to stem from the location of the outboardmost point on Line 1; i.e., the intersection of Plane 1 and the vehicle exterior surface. As explained above, that intersection is located at the outermost edge of the roof, with the door open. After examining your illustration, we believe that this intersection is marked "point *2." If you have any further questions, please feel free to contact George Feygin of my staff at (202) 366-2992. Sincerely, Jacqueline Glassman Enclosure
|
2005 |
ID: GF003171OpenMr. Timothy C. Murphy Dear Mr. Murphy: This responds to your April 8, 2005, letter asking about clearance lamp location requirements for trailers equipped with outboard fenders. Your letter and accompanying diagrams show a dual axle trailer equipped with outboard fenders each extending approximately 10 inches from the main body of the trailer. The outer edges of the fenders are the widest part of the trailer. Specifically, the main body of the trailer measures 81 inches, and the distance between the outer edges of the trailer measured at the fenders is 102 inches. You intend to install both front and rear clearance lamps on the top of each fender, instead of on the main body of the trailer. You ask whether this is permissible under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices and Associated Equipment. Table II of FMVSS No. 108 specifies that for a trailer with an overall width of 80 inches or more, the front and rear clearance lamps must be located "to indicate the overall width of the vehicle . . . and as near the top thereof as practicable." As explained in our March 4, 1996, letter to Mr. Jerry Clay, when the widest part of a trailer is the outer edge of the fender, locating the front and rear clearance lamps on the fender satisfies the requirements of FMVSS No. 108 because the lamps would indicate the overall width of the trailer (see also, our September 4 letter to John W. Cook). By contrast, locating the clearance lamps on the main body of the trailer would not adequately indicate the overall width of the vehicle. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992. Sincerely, Jacqueline Glassman NCC-112:Gfeygin:mar:5/13/05:62992:OCC 003171 |
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.