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: aiam4276OpenMr. John F. Doerr, 100 Lefferts Ave. 4D, Brooklyn, NY 11225; Mr. John F. Doerr 100 Lefferts Ave. 4D Brooklyn NY 11225; Dear Mr. Doerr: This is in reply to your letter of December 12, 1986, to Secretary Dol on your 'Safety Light Warning System.' You have asked if your system 'could legally be implemented' and for advice 'how I may go about marketing this system.'; The patent drawing of your device depicts a light bar mounted in th rear window area with a green lamp in the center flanked by amber lamps, with two red lamps at the end. This system would be acceptable neither as original equipment on passenger cars, nor as replacement equipment on passenger cars manufactured on or after September 1, 1985. As of that date, Federal Motor Vehicle Safety Standard No. 108 requires passenger cars to be manufactured with a red stop lamp in the approximate location of your green lamp. There is no Federal prohibition against offering the system in the aftermarket for retrofitting on passenger cars manufactured before September 1, 1985, but the system would be subject to the laws of each State in which it would be sold or used. I understand that Oregon and California allow green-amber-red deceleration warning systems when the lamps are mounted on the rear of the car, but restrictions may exist as to their mounting in a vehicle's interior.; I hope this information is useful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3419OpenMr. William W. Ardent, Midwest Polychem, Ltd., 1920 S. Kilbourn Avenue, Chicago, IL 60623; Mr. William W. Ardent Midwest Polychem Ltd. 1920 S. Kilbourn Avenue Chicago IL 60623; Dear Mr. Ardent: This responds to your recent letter asking whether the packaging sea of a brake fluid container you intend to market would comply with Safety Standard No. 116.; Safety Standard No. 116, *Brake Fluids* (49 CFR 571.116), specifie performance and labeling requirements for motor vehicle brake fluids and their containers. Paragraph S5.2.1 of that standard sets forth specific requirements for container sealing of brake fluid packages:; >>>Each brake fluid or hydraulic system mineral oil container with capacity of 6 fluid ounces or more shall be provided with a resealable closure that has an inner seal impervious to the packaged brake fluid. The container closure shall include a tamper-proof feature that will either be destroyed or substantially altered when the container closure is initially opened.<<<; The tamper-proof feature on your proposed brake fluid package consist basically of a simple piece of adhesive that is connected between the container cap and the container cylinder. This piece of adhesive is torn in half when the cap is removed from the container, and it appears that the adhesive could not be removed from the container intact. Therefore, strictly speaking, the adhesive feature meets the requirements of S5.2.1 that the tamper-proof feature 'either be destroyed or substantially altered when the container closure is initially opened.' There may be some question whether the adhesive feature is actually tamper-proof, however, since the adhesive could be totally removed from the container without leaving any indication. Nevertheless, since the standard does not define the term 'tamper-proof,' we would have to say that your adhesive seal complies with the requirements of Safety Standard No. 116.; We believe that you should make an effort to improve the design of thi tamper-proof feature, even though it might meet the 'letter of the law' as far as Safety Standard No. 116 is concerned. For example, the adhesive seal should be more difficult to remove, or it should bear some legend indicating that the package has been opened if the seal is broken. We hope that you will voluntarily make these design improvements.; I would like to point out that this letter only represents the agency' opinion based on the information supplied in your letter. The agency does not grant prior approval of the design of motor vehicles or equipment. It is up to the manufacturer to make the final determination whether its vehicles or equipment are in compliance with all applicable Federal motor vehicle safety standards, and to certify that compliance.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1424OpenMr. Robert J. McIntosh, McIntosh & Boynton, Attorneys At Law, 1224 Seventeenth Street, N.W., Washington, DC 20036; Mr. Robert J. McIntosh McIntosh & Boynton Attorneys At Law 1224 Seventeenth Street N.W. Washington DC 20036; Dear Mr. McIntosh: This is in reply to your letter of February 19, 1974, forwarding to u for approval a draft notification letter regarding the Checker front seat adjuster (CIR-727).; The one remaining problem we have with your letter is in the secon paragraph. Because Checker is a manufacturer of motor vehicles, the appropriate determination by Checker pursuant to S 577.4(b)(1) is that the defect exists in the motor vehicles in question. Your second sentence should be changed, and may be changed to read, 'The Checker Motors Corporation has determined that a defect which relates to motor vehicle safety exists in some 1972 model Checker vehicles manufactured from December 9, 1971, through April 5, 1972, and results from improperly installed front seat adjuster assemblies.'; We have decided to accept notification letters in which the referenc to 'some' vehicles (S 577.4(b)(2)) is placed in the sentence required by S 577.4(b)(1).; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4626OpenMr. William G. Kinstler American Flatlight Company 414 Richard Road Rockledge, FL 32955; Mr. William G. Kinstler American Flatlight Company 414 Richard Road Rockledge FL 32955; "Dear Mr. Kinstler: This is in reply to your letter with respect to portable illuminated device, called the 'Flatlight.' You have asked for our review of the advertising brochure that you enclosed, and for copies of any regulations regarding this product. I regret the delay in responding. Your brochure indicates that Flatlight is intended for mounting on the door of a motor vehicle, and connects to the battery by a wire. As shown, it contains a corporate logo, which 'emits a pleasant glow.' The purpose is to readily identify the presence of 'Real Estate Companies and other Sales Agents who need to meet clients at night.' This agency establishes the Federal motor vehicle safety standards that apply to new motor vehicles and motor vehicle equipment. It also establishes regulations pertaining to safety-related defects in motor vehicles and motor vehicle equipment. As Flatlight is advertised almost exclusively for motor vehicle applications (we note a single remark that it can be used for store and window fronts), it is 'motor vehicle equipment' subject to the jurisdiction of this agency. The only Federal motor vehicle safety standard that applies to portable lighting equipment applies only to warning triangles without self-contained energy sources, and thus does not cover the rectangular Flatlight. The Federal lighting standard on lamps, reflective devices, and associated equipment, permits Flatlight to be installed as original equipment (e.g., installed by the dealer on a new vehicle before its delivery to its first purchaser), if it does not impair the effectiveness of lighting equipment required by the standard. It seems unlikely that the 'glow' of a door mounted Flatlight would impair the effectiveness of the required side marker lamps and reflectors, indeed the device might serve more readily to identify the vehicle at night. We surmise, however, that Flatlight is intended for the aftermarket and for installation on vehicles in use. It appears easily transferable from one vehicle to another. Installation of aftermarket motor vehicle equipment is generally permissible under Federal law. However, the installation is prohibited if it is installed by a motor vehicle manufacturer, distributor, dealer or repair business and if such installation renders inoperative, either wholly or partially, equipment installed in accordance with a Federal motor vehicle safety standard. Installation of Flatlight does not appear to present this possibility. Even though Flatlight is not prohibited under Federal law, you must still determine whether it is permissible under the laws of any State in which it may be installed. We are unable to advise you on State law, but recommend that you consult the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. Finally, because Flatlight is 'motor vehicle equipment' you, as its manufacturer, must notify purchasers and provide a remedy upon any determination by you or this agency that it contains a defect related to motor vehicle safety. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam2121OpenMr. J. C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. J. C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold: This responds to your letter of November 11, 1975, requestin confirmation that a 1976 Ford Motor Company 'deluxe continuous-loop seat belt system' satisfies the requirements of Section 7.1.1 of Standard No. 208, *Occupant Crash Protection*.; Section 7.1.1 requires adjustment of the lap belt portion of a fron outboard seat belt assembly 'by means of an emergency-locking or automatic-locking retractor' and adjustment in most cases of the upper torso portion 'by means of an emergency-locking retractor.' The language permits some single retractor, continuous loop systems as long as the single retractor does 'automatically adjust' the tension of the lap belt portion to prevent excessive slack. Because of the submarining danger of a slack lap belt, the National Highway Traffic Safety Administration (NHTSA) has restricted the acceptability of continuous loop systems under S7.1.1 in two areas.; In the NHTSA's September 25, 1972, letter to Renault to which yo refer, the level of friction in the tongue is discussed and our position is stated that it must have a sufficiently low level to qualify the lap belt portion as 'automatically adjustable.' In your recent demonstration of the tongue frictions in the Ford 1976 'standard' and 'deluxe' continuous loop seat belt systems to NHTSA personnel, we saw no evidence of design deficiency in limited use of those systems.; The other restriction concerns the use of manual and automatic tensio relieving devices on the upper portion of continuous loop systems. In our letters of March 9, 1973, and March 27, 1975 (to General Motors), June 13, 1975 (to Chrysler Corporation), and September 5, 1975 (to Takata-Kojyo), the NHTSA has limited the use of tension relieving devices to the upper torso portion of seat belt assemblies that have 'an individually adjustable lap belt.' It is our view that the 1976 Ford deluxe continuous loop system does not have 'an individually adjustable lap belt' within the meaning of Standard No. 208. In this system slack which is introduced into the continuous loop by the 'window shade' tension relief device on the upper retractor is directly transferred to the lap belt, thus increasing the risk of submarining if a crash should occur. I would like to point out that issues related to tension relief devices are, however, still outstanding in an (sic) NHTSA proposal (Docket 74-32, Notice 1).; I am enclosing a report on 'Comfort and Convenience Analysis o Advanced Restraint Systems' of August 1975. This study, conducted by the NHTSA Safety Research Laboratory on a number of different safety belt designs concludes that: 'Several aspects of the systems caused difficulties or confusion, but the single-loop 'window-shade' feature most frequently produced problems.' In light of our mutual desire to improve safety belt usage levels, I should also like to again recommend to your attention the results of the earlier NHTSA sponsored study 'Sources and Remedies for Restraint System Discomfort and Inconveniences' by Man Factors, Inc., that I sent to your company in January 1975.; Sincerely, James B. Gregory, Administrator |
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ID: aiam2571OpenMr. Jim Beach, Collins Industries, Inc., Box 58, Hutchinson, KS 67501; Mr. Jim Beach Collins Industries Inc. Box 58 Hutchinson KS 67501; Dear Mr. Beach: This confirms your April 19, 1977, conversation with Roger Tilton of m staff concerning the definition of school bus.; The National Highway Traffic Safety Administration (NHTSA) define school bus in a notice issued on December 31, 1975 (40 FR 60033) to mean 'a bus that is sold, or introduced into interstate commerce, for purposes that include carrying students to and from school or related events, but does not include a bus designed and sold for operation as a common carrier in urban transportation.' This definition incorporates by reference the definition of bus (49 CFR Part 571.3) which is 'a motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons.' Therefore, by definition a school bus is a vehicle that carries more than 10 persons (e.g., 10 passengers and a driver). This does not preclude smaller vehicles from transporting school children. Vehicles carrying 10 or fewer persons would not have to comply with the school bus construction requirements.; I am enclosing a copy of the notice that established the school bu definition. If you have further questions, do not hesitate to contact us.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3730OpenMr. C. B. Bright, Jr., C. B. Bright Motor Co., Route 1, Ashland, MS 38603; Mr. C. B. Bright Jr. C. B. Bright Motor Co. Route 1 Ashland MS 38603; Dear Mr. Bright: This is in reply to your letter of July 19, 1983, to Mr. Vinson of thi office. You have asked whether you are violating any Federal standards or regulations by adding 'right side steering, accelerator, brakes & turn signal controls to rural mail carriers delivery vehicles (cars, pickup, jeeps, etc.).' You have told us that you do not modify in any way the left hand side controls with which the vehicle was originally equipped.; Assuming that your modifications do not affect the performance of an of the systems with which the vehicle was equipped by its original manufacturer, your conversion operations would not be prohibited by the National Traffic and Motor Vehicle Safety Act. However, with respect to any new vehicle that you modify which has not yet reached its first purchaser for purposes other than resale, you are required to affix a label identifying you as the alterer and certifying that the vehicle as altered meets all applicable Federal motor vehicle safety standards. This is required by Title 49 Code of Federal Regulations, Section 567.7. I enclose a copy of Part 567 for your information.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2822OpenMs. LaVerne L. Kruckenberg, Engineer, Highway Manufacturing Company, P.O. Box 256, Edgerton, WI 53534; Ms. LaVerne L. Kruckenberg Engineer Highway Manufacturing Company P.O. Box 256 Edgerton WI 53534; Dear Ms. Kruckenberg: This is in reply to your letter of March 1, 1978, to Mr. Vinson of thi office asking whether marker lamps on your new 'bevel designed front Van Trailer' comply with Federal Motor Vehicle Safety Standard No. 108. Specifically, instead of providing two amber clearance lamps, on the trailer front and two amber side marker lamps at the trailer's leading edge, you would install a combination clearance-side marker lamp at 45 degrees on the beveled leading edge of the trailer.; Paragraph S4.4.1 of Standard No. 108 permits a side marker lamp to b combined with a clearance lamp 'if the requirements for each lamp...are met....' This means that the combination lamp in position on the vehicle must meet the requirements of SAE Standard J592e, *Clearance, Side Marker, and Identification Lamps*, July 1972. This standard addresses specific photometric requirements for combination clearance and side marker lamps and I enclose a copy for your information.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3360OpenJohn Kelly, Iowa Department of Transporation (sic), Office of Motor Vehicle Enforcement, 5238 N.W. Second Avenue, Des Moines, IA 50313; John Kelly Iowa Department of Transporation (sic) Office of Motor Vehicle Enforcement 5238 N.W. Second Avenue Des Moines IA 50313; Dear Mr. Kelly: This is in response to your letter of August 29, 1980, in which yo requested our opinion on the odometer disclosure required to be made for reconstructed vehicles. The purpose of the odometer reading is to represent the mileage that a vehicle has travelled. If a vehicle is reconstructed with an older chassis and a new body, then it is the opinion of the National Highway Traffic Safety Administration that the odometer should reflect the mileage travelled by the chassis. Purchasers rely on the odometer as an indication of the safety, reliability, and value of a vehicle. If the mileage which the chassis has been driven is not provided to the purchaser, he could be led into a false sense of security, neglecting needed repairs or inspections. The odometer should therefore be set to the mileage travelled by the chassis. If the odometer is incapable of being set to that mileage, it should be set at zero and a written notice should be placed in the left door frame of the vehicle, specifying the mileage the chassis has been driven and the date the new odometer was installed. If the person who asembles the vehicle does not know the mileage the chassis has been driven, he should state that the mileage is not accurate and should not be relied upon.; Likewise, if a vehicle is constructed from the parts of severa vehicles, the odometer statement must still be completed at the time of sale. If the seller knows the mileage on the various components used to construct the vehicle, he should inform the purchaser of the highest mileage that he knows, or the mileage on the chassis if he knows it. If he does not know the mileage, he will be required to state that the mileage is not accurate and should not be relied upon. This applies to all major mechanical and structural portions of the vehicle and not to items that are replaced periodically such as tires.; You also asked if there are any specifications on three wheel vehicle and homemade mopeds. Section 571.3 of Title 49 of the Code of Federal Regulations defines 'motorcycle' as a 'motor vehicle with motive power having a seat or a saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground.' The vehicle described in the article which you attached to your letter and mopeds fall iwthin this category and the applicable motor vehicle safety standards would apply. Any homemade vehicle, whether a moped or other vehicle, which is driven on the public roads must comply with the applicable safety standards. For your information, I have enclosed a pamphlet which described the existing safety standards and specifies which vehicles must comply with those standards. The standards for motorcycles would apply the vehicles described above.; If you have any further questions, please do not hesitate to write. Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam2988OpenMr. Moe Pare, Jr., Director of Design, Cars & Concepts, Inc., 12500 E. Grand River, Brighton, MI 48116; Mr. Moe Pare Jr. Director of Design Cars & Concepts Inc. 12500 E. Grand River Brighton MI 48116; Dear Mr. Pare: This responds to your March 2, 1979, letter concerning the definitio of the vehicle sub-classification, 'convertible.' Your letter included several Figures of various vehicle designs and asked whether each would be considered a 'convertible' by the National Highway Traffic Safety Administration.; While our regulations do not include a formal definition o 'convertible,' the agency has stated that it considers a convertible to be a vehicle whose 'A' pillar or windshield peripheral support is not joined with the 'B' pillar (or rear roof support rearward of the 'B' pillar position) by a fixed rigid structural member. Therefore, passenger cars equipped with a 'sun roof' or a 'Hurst hatch roof' do not qualify as convertibles, because they have a fixed, rigid structural member in the described location (April 21, 1976, letter of interpretation enclosed). This interpretation applies, moreover, whether the rigid structural member joining the 'A' and 'B' pillars is a hidden reinforcing component or whether the structural member is part of the exterior roof panel.; Given this interpretation, only the Fiat X-19 vehicle desig illustrated in your Figure 5 would qualify as a 'convertible.' Each vehicle design in your other illustrations (Figures 1, 2, 3, 4, 6, 7, 8 and 9) include fixed, rigid structural components joining the 'A' and 'B' pillar sections of the vehicles and, therefore, would not be classified as convertibles. Likewise, the designs would not be considered 'open-body type vehicles' (49 CFR 571.3) for the same reason, the structural member, whether hidden or not, would be considered part of the vehicle top. also, I would point out that the 'open-body vehicle' designation generally refers to multi-purpose passenger vehicles such as 'Jeeps' or 'dune buggies.'; I hope this clarification is responsive to your inquiry. If you hav any further questions please contact Hugh Oates of my office (202-426-2992).; Sincerely, Frank Berndt, Acting Chief Counsel |
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Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.