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: aiam1865OpenMr. A.F. Bleiweiss, P.Eng., Vice President, Dominion Auto, Accessories Limited, 420 Keele Street, Toronto 9, Canada; Mr. A.F. Bleiweiss P.Eng. Vice President Dominion Auto Accessories Limited 420 Keele Street Toronto 9 Canada; Dear Mr. Bleiweiss: This is in response to your letter of March 29, 1975, inquiring as t the permissibility of selling your 'Panamirror' in the United States as aftermarket equipment.; Motor Vehicle Safety Standard No. 111, *Rearview Mirrors*, Provide minimum performance requirements for rearview mirrors on passenger cars and multipurpose passenger vehicles. According to the standard, the inside rearview mirror must furnish the driver with a specified field of view to the rear of substantially unit magnification. Any vehicle manufactured for sale, sold, or introduced into interstate commerce must be equipped with an inside rearview mirror that meets the designated level of performance. It appears that the 'Panamirror' would not satisfy the requirements of the provision, because it is convex in structure and therefore would not provide a view of substantially unit magnification.; If the mirror were installed on a vehicle as aftermarket equipmen (after the vehicle's first purchase for purposes other than resale) in such a way as to render inoperative the inside rearview mirror, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (Pub. L. 89-563) as amended (Pub. L. 93-492) would apply where the installation was accomplished by a manufacturer, distributer, dealer, or motor vehicle repair business. The section prohibits the named parties from knowingly rendering inoperative a system installed in compliance with an applicable motor vehicle safety standard.; Yours truly, James C. Schultz, Chief Counsel |
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ID: aiam1802OpenMr. Fred W. Cords, Minnesota Automotive, Inc., Box 2074, North Mankato, MN 56001; Mr. Fred W. Cords Minnesota Automotive Inc. Box 2074 North Mankato MN 56001; Dear Mr. Cords: This is in reply to your letter of January 6, 1975, requesting a opinion on whether a person who installs a Mico Brake Lock device on a new vehicle before its sale to the first purchaser is required to affix an alterer label in accordance with 49 CFR SS 567.7 and 568.8. You state that you believe the device, which serves as a hydraulic parking brake, is readily attachable because it can be installed in a minimum amount of time and does not in any way alter the operation of the vehicle's original brake system.; The NHTSA will generally abide by a good faith determination on th part of a manufacturer that a device is readily attachable. Such a decision should be based primarily on the intricacy of the installation of the device. Simple tools, a relatively short installation time, and the ability to install the device without extensively modifying the vehicle would all be factors pointing to a decision that a component is readily attachable. You should note that section 567.7 of the Certification regulations also requires an alterer label when the installation of a component invalidates a vehicle's existing weight ratings, whether or not the component is readily attachable. On the basis of your letter, however, it appears to us that this would not occur as a result of installation of the Mico Brake Lock device.; If your device meets these criteria, no additional labeling will b required.; Yours truly, James C. Schultz, Acting Chief Counsel |
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ID: aiam2865OpenMr. Robert B. Kurre, Director of Engineering, Wayne Corporation, P. O. Box 1447, Industries Road, Richmond, IN 47374; Mr. Robert B. Kurre Director of Engineering Wayne Corporation P. O. Box 1447 Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your recent letter asking whether Safety Standard No 208 applies to side-facing seats in multi-purpose passenger vehicle vans. You also ask to be advised of the criteria to be used for the installation of seat belts in these vehicles.; Safety Standard No. 208, *Occupant Crash Protection*, does requir side-facing seats in multipurpose passenger vehicles to comply with one of the options under paragraph S4.2.2, since the side-facing seats in question would be considered designated seating positions. If a manufacturer chooses to install seat belts under one of the options of that paragraph, the seat belt assemblies must comply with Safety Standard No. 209, *Seat Belt Assemblies*, and Safety Standard No. 210, *Seat Belt Anchorages*.; Safety Standard No. 210 does exempt side-facing seats from its strengt requirements, but all other requirements of the standard would be applicable. However, we strongly recommend that belt anchorages for side- facing seats be of at least equivalent strength to anchorages for forward and rearward facing seats, since the strength specifications are only minimum performance requirements. Side-facing seats were excepted from the strength requirements specified in the standard because the forces acting on side-facing seats are different from those acting on forward or rearward facing seats and the requirements and procedures were specifically developed for these latter seats.; Please contact this office if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3059OpenMr. Peter Bigwood, Chief Engineer, Ontario Bus Industries Inc., 5395 Maingate Drive, Mississauga, Ontario; Mr. Peter Bigwood Chief Engineer Ontario Bus Industries Inc. 5395 Maingate Drive Mississauga Ontario; Dear Mr. Bigwood: This responds to your July 16, 1979, letter asking two questions abou the test procedures of Standard No. 217, *Bus Window Retention*, as they apply to buses you manufacture.; First, you ask whether side service doors can be counted in determinin the proper amount of bus emergency exits as required by the standard. As long as side service doors comply with all requirements applicable to emergency doors, they can be considered emergency exits for purposes of compliance with the standard.; Your second question asks whether glazing in a door is tested fo window retention, and if so, whether it is tested while the door is installed in a bus. The answer to both parts of this question is yes. All bus glazing, that is of the minimum size specified in the standard, must comply with the window retention requirement. The intent of the window retention requirement is to prevent openings in buses that might result in the ejection of occupants from the vehicle during an accident. In order for this requirement to have meaning, the glazing must be tested as it is installed in the vehicle to ensure the integrity of both the glazing and its surrounding structure. This means that glazing in vehicle doors is tested while the door is in the normal closed condition. If the door opens during the test, the vehicle would not be in compliance with the requirements.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2622OpenMr. Jerry W. McNeil, Director of Engineering, American Trailers, Inc., Box 26568, Oklahoma City, Oklahoma 73126; Mr. Jerry W. McNeil Director of Engineering American Trailers Inc. Box 26568 Oklahoma City Oklahoma 73126; Dear Mr McNeil: This responds to your May 25, 1977, letter asking whether two sampl certification labels you submitted comply with the requirements of Part 567, *Certification*, and Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*.; The National HIghway Traffic Safety Administration (NHTSA) does no issue advance approvals of compliance with Federal safety standards or regulations. The agency will, however, give you an informal opinion as to whether your labels appear to comply with the requirements. The two labels you submitted do not follow the format required by Part 567 for certification labels. Therefore, they do not appear to comply with the requirements. Your method of stating tire and rim sizes differs from that required in Part 567 and Standard No. 120. For example, you state your tire and rim information as follows: '10-20-f-Tires-7.5 Rims at 75 PSI Cold Dual.' By the requirements of Part 567 and Standard No. 120 as they apply to certification labels, this information should read: '10.00-20(f) tires, 20x7.5 rims, at 75 psi cold dual.' Further, the statement after GAWR 'maximum with minimum size tire-rims shown below' should be deleted from the certification label. I am enclosing a copy of Part 567 and Standard No. 120 for your information.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0873OpenMr. Heinrich von Wimmersperg, Development Engineer, 15929 Grand River Avenue, Detroit 27, MI; Mr. Heinrich von Wimmersperg Development Engineer 15929 Grand River Avenue Detroit 27 MI; Dear Mr. von Wimmersperg: Thank you for your letter of October 2, 1972, concerning the For 'Tot-Guard' and your child restraint patents.; The consumer complaints that we have received on the Ford Tot-Guar have been complaints focussing on the fit of the device for minimum recommended size children. The comments relate both to the ease with which small children may climb out of the device and slide under it, as well as to the vision restriction problem for the small child.; The Tot-Guard has proven to perform well in 30 mph frontal impacts wit the three- year-old child dummy in our research programs, but can be improved in lateral protection capability and in performance with the 50-pound child dummy.; We have just completed a research program to develop new concepts i child restraints and will very shortly be making these designs available for any manufacturer who chooses to produce one of these advanced design restraints.; A copy of your letter will be placed in the public docket along wit plans for the restraints developed on our child restraint development contract.; We are interested in reviewing and placing in the public docket copie of your designs for the infant car bed, which you mention in hopes of stimulating the production of a crashworthy design for such a device.; We appreciate your letter and are looking forward to hearing from yo in the near future.; Sincerely, Douglas W. Toms, Administrator |
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ID: aiam4257OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Dept., Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of November 21, 1986, with reference t the distance between a front turn signal lamp and a lower beam headlamp.; In brief, SAE Standard J588e, incorporated by reference in Standard No 108 requires a minimum separation distance of 4 inches between the optical axis (filament center) of the front turn signal lamp to the inside diameter of the retaining ring of the lower beam headlamp. You have pointed out that a replaceable bulb headlamp does not have a retaining ring, and you have presented two possible substitutes as a measuring point. The first (your Item A) is the outer edge of the headlamp, and the second (your Item B) is the end of the effective area of the reflector. You believe that Item B is the more appropriate.; We concur with your interpretation. Of the two options, the distance t the edge of the effective area of the reflector is the one most similar to the inside diameter of the retaining ring of the lower beam headlamp. The basis for this interpretation is the assumption that the headlamp lens between the outer edge of the headlamp and the edge of the effective area of the reflector is not used for production of the lamp's beam, has no significant luminance, and therefore will not mask the turn signal.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0989OpenMr. Orin D. Miner, P.O. Box 138, Palmyra, Wisconsin 53156; Mr. Orin D. Miner P.O. Box 138 Palmyra Wisconsin 53156; Dear Mr. Miner: Contact 6 of Milwaukee, Wisconsin has sent us a copy of your lette asking that we respond to your questions.; In your letter you inquire as to the distribution of fines collecte from tire manufacturers as a result of their manufacturing tires that do not comply with the requirements of the Federal standard for passenger car tires (Standard No. 109).; Monies collected as settlement offers are transmitted to the genera funds of the United States Treasury.; The Federal Motor Vehicle Safety Standard, including the passenger ca tire standard, are minimum standards vehicle manufacturers and equipment manufacturers are required to meet. They are issued to give assurance that if the product in question meets the standards the public will have some protection against unreasonable risk of death or injury.; In addition to the question of civil penalties, manufacturers o non-conforming vehicles or tires are usually required to issue a defect notification and are urged to replace the defective equipment. Your complaint does not appear to be concerned with a safety related problem but rather with tires that you believe have not given you adequate treadwear. This is not area covered by existing standards, however, this agency has under consideration a quality grading regulation which would include grading requirements for the treadwear life of each tire manufactured after a given date.; Concerning your recommendation that Federal inspectors be placed i tire manufacturers' plants, has been considered at various times and the agency's present thinking is that the cost and manpower involved would not warrant this course of action.; Thank you for your interest in auto safety and your view in this area. Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4832OpenMr. Billy S. Peterson President Automotive Safety Testing, Inc. at TRC of Ohio, Bldg. 20 Rd. 152 & SR 33 East Liberty, OH 43319; Mr. Billy S. Peterson President Automotive Safety Testing Inc. at TRC of Ohio Bldg. 20 Rd. 152 & SR 33 East Liberty OH 43319; Dear Mr. Peterson: This is in reply to your letter of February 7, l99l to the Office of Chief Counsel asking for a clarification of allowable mounting locations and photometric output requirements for tail/stop lamps on passenger cars. One of your clients wishes to mount 'two-part' stop/tail lamps 'so that one lamp is mounted on the fixed quarter panel and a duplicate lamp is mounted on the trunk lid.' Each part of the two-part lamp is a combination tail/stop lamp. You have asked whether the minimum photometric requirements must be met by 'the lamp mounted to the quarter panel or may the portion mounted on the trunk lid count toward the photometric requirements.' Your 'two-part lamp' would be treated as two separate lamps. For purposes of compliance, only one of these two adjacent lamps must be designed to conform to Standard No. 108, and this conformance must be independent of any 'contribution' by the adjacent lamp. Although Standard No. 108 permits either the deck or the body mounted lamp to be the complying lamp, it would be our preference that the body mounted lamp be the one that complies, so that the benefit of a conforming stop/tail lamp would be realized during those occasions when the lid may be raised. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2174OpenMr. R. D. Coughlin, Vice President, Rol'on America, Inc., Melbourne, FL 32901; Mr. R. D. Coughlin Vice President Rol'on America Inc. Melbourne FL 32901; Dear Mr. Coughlin: This is in response to your letter of December 10, 1975, regarding th applicability of existing Federal regulations to the manufacture of 'Helmate.'; At the present time, there is no regulation pertaining directly to th type of helmet accessory your corporation produces. The general regulation concerning motorcycle helmets is 49 CFR S 571.218, Motor Vehicle Safety Standard No. 218, *Motorcycle Helmets*. This standard establishes minimum performance requirements for helmets designed for use by motorcyclists and other motor vehicle users.; If a manufacturer, distributor, dealer, or motor vehicle repai business were to install 'Helmates' on helmets, the helmets would have to remain in conformity with the requirements of Standard 218. However, persons other than manufacturers, distributors, dealers, and repair businesses may modify products, after purchase by a user, without regard to the requirements of a Federal safety regulation. Thus, if 'Helmate' is mounted on the helmet by an ordinary consumer, safety Standard 218 is inapplicable.; There is some question as to whether motorcycle helmets will still mee the performance requirements of Standard 218, after the 3/8 inch hole required to mount the 'Helmate' is drilled. If it becomes apparent that installing 'Helmate' type helmet accessories causes the performance level of helmets to drop below the requirements of Standard 218, the NHTSA might find it necessary to enact regulations to rectify the situation. Our main concern is to assure that motorcycle helmets afford riders the protection and safety needed.; If I can be of any further assistance, please feel free to write. Yours truly, Richard B. Dyson, Assistant 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.