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: 12311.ztvOpen Mr. Craig Homberg Dear Mr. Homberg: This responds to your letter of August 2, 1996, to the former Chief Counsel, Samuel Dubbin, asking for suggestions as to where Aquatech might locate the rear identification lamps on a vehicle that it manufactures. These lamps "are obstructed by a vacuum boom." The lamps cannot be mounted on the boom because it "articulates side to side and extends and retracts." You have enclosed a two-dimensional drawing showing the vehicle from the rear. Table II of Motor Vehicle Safety Standard No. 108 requires rear identification lamps to be "3 lamps as close as practicable to the top of the vehicle, as close as practicable to the vertical centerline, with lamp centers spaced not less than 6 inches or more than 12 inches apart." Table II does not establish either a minimum or maximum mounting height for these lamps. The agency realizes that, with some vehicle configurations, the highest practicable location may be approximately the same level as stop and taillamps, such as the frame rail, and the agency has accepted this. Some manufacturers have also added equipment to the vehicle at this level to accommodate identification lamps. The two-dimensional drawing you enclosed shows a horizontal structure below the boom and above the rear axle, where it might be possible to add identification lamps. However, the drawing is two-dimensional and it is not possible for us to assess the dimensional relationship between the horizontal structure and the vertical piece that, in the picture, bisects the lower half of the horizontal structure. If it is not practicable to add identification lamps on the horizontal structure below the boom and above the rear axle, we would be pleased to advise you further if you would send us a photograph or drawing of the rear that shows the dimensional relationships of the equipment already located there. If you have any further questions, you may call Taylor Vinson of this Office (202-366-5263). Sincerely, John Womack Acting Chief Counsel ref:108 d:9/6/96 |
1996 |
ID: 12328.ztvOpen Julius Fisher, Esq. Re: U.S. Patent No. 5,389,913 Warning System for Vehicles Your file Jodee P-8A Dear Mr. Fisher: This is in reply to your letter of August 6, 1996, to the former Chief Counsel, Samuel Dubbin, with respect to whether a warning system for motor vehicles which you describe would be permitted by paragraph S5.1.3 of Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment (49 CFR 571.108). As you describe it, the system "provides a visual indication of a warning situation through use of the parking lamps, high beam headlamps, and back-up lamps." The system operates as follows: "when the horn is sounded, electrical circuits are energized . . . which cause the high beam of the headlamps to flash on and off, in synchronism with the flasher. If the high beams or back-up lamps are already in their 'on' state, they will change to a 'flashing' state." In addition, the parking lamps are activated in a steady-burning state when the horn is sounded (no change takes place if the parking lamps are already on). If the lower beams are on when the horn is sounded, there is no change either; only the upper beams begin to flash. We note from reading the patent that the system incorporates an "off relay delay" which "is set for a predetermined time during which it stays in its on state after being energized. This predetermined time might be for five seconds." We note also that the system may be extended to other lamps but that the inventors have not chosen to do so because "such might produce confusion and/or an inappropriate response." Finally, we note that the flash rate is unspecified but can be changed. A range of from a quarter of a second to a second is mentioned. Standard No. 108 establishes lighting requirements that a motor vehicle must meet up to the time it is first purchased in good faith other than for resale. When a vehicle has been manufactured to conform with Standard No. 108, a dealer must not add optional equipment that creates a noncompliance. The principal provision of Standard No. 108 that affects the warning system is paragraph S5.5.10 which prescribes wiring requirements for lighting equipment in use. Under paragraph S5.5.10(b) "Headlamps and side marker lamps may be wired to flash for signaling purposes". However, under paragraph S5.5.10(d), "All other lamps shall be wired to be steady-burning." This means that it is permissible under paragraph S5.5.10(b) for the upper beam headlamps to flash, but the warning system would create a noncompliance with paragraph S5.5.10(d) when the back-up lamps flashed. The acceptability of optional lighting equipment is also dependent upon paragraph S5.1.3 which forbids the addition of any equipment "that impairs the effectiveness of lighting equipment required by this standard." The warning system's activation of the parking lamps would not appear to have an impairing effect on the front lighting equipment required by Standard No. 108. Nor can we conclude that a flashing of the upper beam when the lower beam is on would have an impairing effect. Under Federal law, the acceptability of the warning system as an item of equipment sold in the aftermarket is determinable by 49 U.S.C. 30122. This section prohibits manufacturers, distributors, dealers, and motor vehicle repair businesses from "making inoperative" any device or element of design installed in accordance with a Federal safety standard. As we have discussed, the system would create a noncompliance in the operation of the back-up lamp, which, in our opinion, is the same as making it inoperative. However, this prohibition does not apply to an owner who installs the warning system. Nevertheless, the warning system would remain subject to acceptability under local laws. We are unable to advise you on these and suggest that you consult local officials in areas where the inventors would like to sell their warning system. We appreciate the concern shown in the patent that the system not create confusion and/or an inappropriate response from other drivers. But we believe it more likely than not that a driver ahead of a vehicle equipped with the warning system will indeed be confused when confronted with the sounding of a horn and the sudden presence of flashing upper beam headlamps in the rear view mirrors, and will not understand the "message" that is being conveyed. How this might impact safety is speculative. But with the increasing trend towards aggressive drivers on the roads, a system of this nature could be subject to abuse, even if its flash rate and duration were standardized and immutable. If you have further questions, you may refer them to Taylor Vinson of this Office (202-366-5263). Sincerely, John Womack ref:108#VSA |
1996 |
ID: 12339.ZTVOpen Mr. Paul J. M. Angrisano, III FAX: 504-558-0969 Dear Mr. Angrisano: On August 29, 1996, we responded to your letter which we received on August 14, 1996, with respect to whether it is permissible to alter daytime running lamps without violating a Federal regulation. I would now like to clarify a statement in that letter. You asked for confirmation that "no installer or individual who disconnects or alters existing Daytime Running Lights on a 1997 vehicle is in violation of any federal law. Alteration of Daytime Running lights is completely legal at the owners discretion." We confirmed your statement, and replied that, while Standard No. 108 contains specifications for daytime running lamps (DRLs), it does not require manufacturers to provide them. Although there is a statutory prohibition (Title 49, United States Code Sec. 30122) that manufacturers, distributors, dealers and motor vehicle repair businesses may not make inoperative any device or element of design installed in accordance with a Federal motor vehicle safety standard, this prohibition does not apply to DRLs because a motor vehicle need not be equipped with DRLs in order to comply with Standard No. 108. Although a manufacturer is not required to provide DRLs, Standard No. 108 specifies performance requirements that DRLs must meet if a vehicle is equipped with them. The clarification I wish to provide is that manufacturers, distributors, dealers and motor vehicle repair businesses, while free to disconnect DRLs or provide on-off switches, may not alter the performance specifications of DRLs in a manner that would make them not comply with the performance requirements specified for DRLs in the standard. The specified performance requirements exist specifically to prevent impairment of the performance of other lighting equipment, such as turn signals, from performing the function for which they are intended, or impairment of rearview mirrors through the creation of glare. We would regard these circumstances as a "making inoperative" within the meaning of the statutory phrase. If a dealer or distributor performed such a modification before the initial sale of a vehicle, we could view this as a noncompliance with Paragraph S5.1.3 of Standard No. 108. If you have any further questions, you may call Taylor Vinson of this Office (202-366-5263). Sincerely, John Womack Acting Chief Counsel ref:108 d:9/30/96 |
1996 |
ID: 12341.jegOpen Mr. Guy Monagas Dear Mr. Monagas: This responds to your letter asking what DOT standards would apply to a seat belt system you have designed. I apologize for the delay in our response. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue safety standards for new motor vehicles and new motor vehicle equipment. The agency does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to certify that their vehicles and equipment meet applicable standards. NHTSA has issued four safety standards concerning safety belt systems. The first is Standard No. 208, Occupant Crash Protection (49 CFR 571.208), which sets forth requirements for occupant protection at the various seating positions in vehicles. The second is Standard No. 209, Seat Belt Assemblies (49 CFR 571.209), which sets forth strength, elongation, webbing width, durability, and other requirements for seat belt assemblies. The third is Standard No. 210, Seat Belt Assembly Anchorages (49 CFR 571.210), which establishes strength and location requirements for seat belt anchorages. The fourth is Standard No. 302, Flammability of Interior Materials (49 CFR 571.302), which specifies burn resistance requirements for materials used in the occupant compartment of motor vehicles. I regret that we are not able to provide an analysis of the requirements of the standards in light of your specific design. Enclosed is an information sheet we have prepared to provide general information for new manufacturers of motor vehicles and motor vehicle equipment. Also enclosed is a copy of an information sheet explaining how to obtain copies of our standards. I hope this information is helpful. If you have further questions, please feel free to call Edward Glancy of my staff at (202) 366-2992. Sincerely, Enclosures |
1996 |
ID: 12371-2.pjaOpen Mr. Thomas M. Joyce Dear Mr. Joyce: This responds to your letter requesting an interpretation on whether the tilt bed trailers your company manufactures would be excluded from the National Highway Traffic Safety Administration's (NHTSA) recent rear impact protection (underride guard) regulations. As shown in the product literature and videotape you enclosed with your letter, your trailers are equipped with hydraulic traveling rear axles. These axles move fore and aft under the frame rails of the vehicle in conjunction with hydraulic pistons at the front of the bed to tip the bed of the trailer down in the rear until it contacts the ground. Once tipped, containers, construction equipment, and wrecks can be driven or pulled by a hoist cable on and off the bed. Based on your product literature and videos, it appears that your factory mounts this equipment on new truck and trailer chassis prior to first sale. You believe that these trailers are excluded due to their "special design." We assume you mean that you believe the vehicles are excluded as "special purpose vehicles," because mounting underride guards on the rear underside of the rails which would prevent them from being fully lowered. The short answer to your question is that your trailers are not excluded. Federal Motor Vehicle Safety Standard (FMVSS) No. 224, Rear impact protection, requires most trailers and semitrailers weighing over 10,000 pounds to be fitted at the rear with a rear impact (underride) guard meeting the requirements of FMVSS No. 223, Rear impact guards (49 CFR 571.223 and 571.224, published on January 24, 1996 at 61 FR 2004). The only excluded category of vehicle that is relevant for the purposes of this letter is special purpose vehicles. A special purpose vehicle is defined in S4 of FMVSS No. 224 as being "a trailer or 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 . . . (emphasis added)." Your tilt bed trailer is not excluded, because it does not meet the definition of a special purpose vehicle. Although NHTSA considers the rails to be work performing equipment that, as the frame is tilted, passes through the area where the horizontal member of the underride guard would be located, they do not do so while the vehicle is in transit. NHTSA addressed the issue of roll off hoist trailers in the final rule. The National Solid Wastes Management Association (NSWMA), a trade group that we believe represents many of your customers, requested special consideration for roll-off hoist vehicles. However, NSWMA's main objection was requiring guards on the containers themselves, which is not your concern. NSWMA stated in their comment that: [t]he most common type of roll-off tilt frame used is the 'outside rail' design . . . In these cases the rear underride [guard] required by [23 CFR] 393.86 will contact the ground at a frame tilt angle of approximate [sic] 40 degrees. Since this causes instability if the ground is uneven, a number of manufacturers have resorted to a retractable underride [guard] design, where a strut attached to the rear chassis frame will cause the underride [guard] to move forward and out of the interference area as the frame is tilted. NHTSA assumed by this comment that a design solution had been found to address the problem of the guard hitting the ground. Therefore, NHTSA believed it was only necessary to respond to NSWMA that guards were not required on the container, only the trailer that carries it. We note that your current design already is nearly compliant with the configuration aspects of the rule. The drawing you sent us shows that the guard is mounted to the back of the traveling rear axle and extends rearward from the axle. One drawing shows the rear surface of the guard's horizontal member within two inches of the required zone. Perhaps extending the mounting struts rearward another two inches would produce a compliant guard. Alternatively, you could contact NSWMA to explore the possibility of using the retractable guard design that it discussed. If you believe your trailers should be excluded from Standard No. 224, you may submit a petition for rulemaking (see 49 CFR Part 552, which I have enclosed for your convenience) requesting that NHTSA amend the standard. If you have any further questions, please feel free to contact Paul Atelsek of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel ref:224 d.12/10/96 |
1996 |
ID: 11654DRNOpen Mr. John A. Silva Dear Mr. Silva: This responds to your letter advising us that your company is developing a product in the "automotive safety field," and asking for guidance about how this agency=s requirements may affect your product. 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 equipment. Enclosed is an information sheet, "Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment,@ describing NHTSA=s regulations for motor vehicle and motor vehicle equipment manufacturers. Under the agency=s governing statute, NHTSA does not certify or approve products. Instead, each manufacturer is responsible for "self-certifying" its products to all applicable safety standards. You did not specify in your letter what type of automotive product you plan to manufacture, and thus our guidance on our standards is limited. Please write to us again when you can provide more details about your product. If you are concerned about maintaining confidentiality about business information concerning your product, this agency has procedures at 49 CFR Part 512, Confidential Business Information, under which NHTSA will consider claims that information you submit to us is confidential business information as described in the Freedom of Information Act. You also state that your product may require patent protection. For guidance on patent matters, I would suggest that you consult an attorney with expertise in patent law, who can provide specific guidance about your product. If you have questions about NHTSA=s requirements or any other matter, please feel free to contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely,
Samuel J. Dubbin Chief Counsel Enclosure ref:571 d:4/3/96
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1996 |
ID: 11655DRNOpen Mr. Roger Wilk Dear Mr. Wilk: This responds to your letter asking for information on regulations Apertaining to the horn used as a warning device on an automobile.@ The National Highway Traffic Safety Administration (NHTSA) does not require a horn on motor vehicles. Our safety standard for motor vehicle controls and displays (Safety Standard No. 101, 49 CFR '571.101) specifies requirements for a horn if one is provided. The horn must be operable by the driver, and must be identified as specified in the standard. I am enclosing a copy of Standard No. 101 for your information. Our sister agency in the Department, the Federal Highway Administration (FHWA), has operational and equipment requirements for commercial vehicles used in interstate commerce. For further information about FHWA requirements, you can contact that agency's Chief Counsel's office at (202) 366-0650. In addition, some States regulate the use of horns. You have provided an excerpt (Section 12-401 "Horns and other Warning Devices") from the Uniform Vehicle Code and Model Traffic Ordinance. The Code is not a Federal statute, but is available for enactment by the States. You may be able to determine whether Illinois or any other State has enacted Section 12-401 by contacting: Automotive Manufacturers Equipment Compliance Agency, Inc. 888 16th St., NW, Suite 700 Washington, DC 20006 Tel.: (202) 898-0145; FAX (202) 898-0148 I hope this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely,
Samuel J. Dubbin Chief Counsel Enclosure ref:571#101 d:4/5/96
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1996 |
ID: 11656-1PJAOpen Mr. Claude Sauvageau, P.Eng. Dear Mr. Sauvageau: This responds to your letter asking about emergency exit labeling requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 217, Bus emergency exits and window retention and release. You ask which of two labels your client, an urban bus manufacturer, should use on their emergency exit windows. As required by S5.3.1 of Standard No. 217, two motions are necessary to open the exits of your client=s buses. The first is to pull down on a red latch at the top center of the window. The second is to push to the left a handle at the bottom right of the window. Your first label depicts only the action of pulling down the red latch. Your second label shows the sequence of first pulling down the red latch and then pushing the handle to the left. You are correct in your assumption that only the second emergency exit label is permitted. The language in S5.5.1 requires the label to have A. . . the designation >Emergency exit= followed by concise operating instructions describing each motion necessary to unlatch and open the exit . . .@ (emphasis added). The word Aeach@ explains that all necessary motions have to be described. The words Aand open@ explicitly include the motion to open the window. The first label only tells how to unlatch the window, not how to open it. The second label tells how to unlatch and open the window. I hope this information is helpful. If you have any further questions, feel free to contact Paul Atelsek of my staff at 202-366-5260. Sincerely,
Samuel J. Dubbin Chief Counsel ref:217 d:4/29/96
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1996 |
ID: 11658DRNOpen Mr. Louis Kleinstiver Dear Mr. Kleinstiver: You have asked me to explain the effect of differing State and Federal definitions of school buses on the obligations of vehicle dealers. The Federal definition of "school bus" affects the scope of the Federal requirements only, while the definitions of the various States affect the scope of State school bus requirements only. The Federal definition determines which new vehicles sold or leased by dealers are required under Federal law to meet the Federal motor vehicle safety standards for school buses. The definitions of the various States determine which vehicles are subject to the State operational requirements for school buses. Under Federal law, a "bus" is any vehicle, including a van, that has a capacity of 11 persons or more, including the driver. A bus is a "school bus" if it is to be used to transport children to and from school or school-related events. If a State chooses to define "school bus" to include only buses with a capacity of 16 persons or more, that definition would not affect the obligations of dealers in selling or leasing 11 to 15-person buses under Federal law. If a dealer sold or leased a new bus of this size for school transportation, the dealer would nevertheless have to ensure that the bus was certified to the Federal motor vehicle safety standards for school buses. A dealer selling or leasing a new bus for school use that does not meet the school bus standards would be subject to a civil penalty. As you requested, I am enclosing two question-and-answer sheets about school bus issues, one of interest to motor vehicle dealers, and another of general interest. I am also enclosing copies of two interpretation letters. The first letter, dated December 29, 1977, is addressed to the Kentucky Department of Education, and concerns the applicability of our school bus standards to vans. The second letter, dated November 25, 1985 to Thomas Built Buses, explains that NHTSA considers a Head Start facility as a preprimary Aschool@ for the purpose of NHTSA's school bus standards. In addition, some vehicle manufacturers have written guidelines to assist their dealers to determine whether vehicles are being sold for use by schools and school districts. Dealers should contact their manufacturers for any such information. If you have any questions regarding Federal school bus requirements, please contact Ms. Dorothy Nakama of my staff at (202) 366-2992. Sincerely,
Samuel J. Dubbin Chief Counsel Enclosures ref:571.3 d:4/17/96
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1996 |
ID: 11660ZTVOpen Mr. Yoshiaki Matsui Dear Mr. Matsui: We have received your letter of March 13, 1996, asking for an interpretation of the word "replaceable" with respect to the replaceable light sources permitted by Motor Vehicle Safety Standard No. 108 for use in motor vehicle headlamps. This information will assist you in the development of HID headlamps. You ask whether "replaceable" as used in paragraph S7.7 means that access should be provided for convenient replacement without the use of special tools, which is a specific requirement of Standard No. 108 for light sources for the center highmounted stop lamp. The answer is no; there is no requirement that replaceable light sources be replaceable without the use of special tools. We recognize that HID light sources may be designed for the life of the vehicle on which they are installed, and, optimally, would require replacement only in the event of front end damage. However, NHTSA believes it is in the interest of safety that light sources that are not designed for such longevity should be replaceable in a simple manner. When the agency amended Standard No. 108 to permit replaceable light sources (48 FR 24690, June 2, 1983), the replaceable light sources that were initially produced had bayonet mountings, which provided positive one-way insertion of the bulb into the reflector assembly. This allowed owner-replacement of the light source, a safety benefit used in justification of the final rule: "The easy replacement of the bulb may result in faster replacement of burned out headlamps." Thirteen years later, headlighting systems have become more complicated in a way that the agency did not foresee then, but the principle of simplicity of replacement of the light source remains. If you have further questions you may refer them to Taylor Vinson of this Office (FAX 202-366-3820). Sincerely, Samuel J. Dubbin Chief Counsel ref:108 d:4/24/96
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1996 |
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.