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: aiam1853OpenMr. Leonard F. Blanda, Director of Safety, CINCUSAREUR, APO NY 09403; Mr. Leonard F. Blanda Director of Safety CINCUSAREUR APO NY 09403; Dear Mr. Blanda: This responds to your question whether a recent amendment of Standar No. 208, *Occupant crash protection*, which modified the requirement for a seat belt warning system, would make legal the disconnection of warning systems which conformed to earlier requirements.; The answer to your question concerning vehicle owners is yes Disconnection of safety devices is subject to a Federal statue, the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391 et seq.), as recently amended (P.L. 93-492). For your information, I will summarize the relevant provisions on disconnection.; The Safety Act prohibits knowing disconnection of safety devices afte the first retail sale, as well as before this sale, with three exceptions.; First, after December 26, 1974, a *private party* may disconnect *any devices *after* sale. Generally, a manufacturer, distributor, dealer, or repair business may not knowingly disconnect safety devices except during repair of the vehicle.; Second, after December 26, 1974, any person, including a new ca dealer, may disconnect the ignition interlock and *continuous* buzzer (but *not* the warning *light*) at any time *after* sale of 1974- or 1975-model passenger car. This does not include the 8-second buzzer found on the newest 1975 models.; Third, a *dealer* may disconnect the ignition interlock an *continuous* buzzer (but *not* the warning *light) at the request of the first purchaser *before sale* of the new vehicle. This is the only exception to the rule that no person may disconnect any safety devices prior to sale. This does not include disconnection of the 8-second buzzer found on the newest 1975 models.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam5113OpenMr. Terry Wagar Technical Services Bureau State of New York Department of Motor Vehicles Division of Vehicle Safety Services The Governor Nelson A. Rockefeller Empire State Plaza Albany, NY 12228; Mr. Terry Wagar Technical Services Bureau State of New York Department of Motor Vehicles Division of Vehicle Safety Services The Governor Nelson A. Rockefeller Empire State Plaza Albany NY 12228; "Dear Mr. Wagar: This responds to your letter asking about the repai of glazing in in-service motor vehicles that were originally designed to comply with Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205). You were specifically concerned about the safety of a repair process known as 'Ultra B-O-N-D' which you explained involves injecting a liquid through a crack in a windshield. The repaired area is then exposed to a lamp, scraped with a razor blade, and cleaned. You explained that after this process is completed, the crack is 'not as visible.' By way of background information, the National Traffic and Motor Vehicle Safety Act (Safety Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards applicable to new motor vehicles and new motor vehicle equipment. Pursuant to this authority, the agency has issued Standard No. 205, which establishes performance requirements for all windows (called 'glazing' in the Standard) in new motor vehicles and for all new replacement windows for motor vehicles. The Federal motor vehicle safety standards do not apply to vehicles and motor vehicle equipment after their first sale to a consumer. The Safety Act does include a provision that prohibits manufacturers, distributors, dealers and motor vehicle repair businesses from 'rendering inoperative' any device or element of design installed on or in a motor vehicle in compliance with an applicable Federal motor vehicle safety standard. However, that provision does not require those entities, in repairing a damaged vehicle, to restore it to its original level of performance. The States do have the authority to regulate motor vehicle repairs and the condition of in-service vehicles, and this agency encourages them to take steps to ensure the safe operating condition of vehicles-in-use. (The Federal Highway Administration has in-service requirements for commercial motor vehicles used in interstate commerce.) I regret that we are unable to provide any information concerning the safety of the 'Ultra B-O-N-D' process. We suggest that, in developing criteria for the condition of in-use glazing, including the permissibility of certain types of repairs, that you consider such factors as whether particular damage, even after repair, would adversely affect driver visibility, would likely become more serious during normal use (e.g., a small crack becoming a large crack), would reduce the ability of the windshield to retain unrestrained occupants in the vehicle, or would otherwise adversely affect vehicle safety. In addition, if the windshield is so extensively damaged that it cannot be repaired using the 'Ultra B-O-N-D' process, and must be replaced, the new windshield should be installed in accordance with the vehicle manufacturer's instructions. In the event of an accident, an improperly installed windshield may allow unrestrained occupants to be ejected from the vehicle with resulting personal injury. I hope this information is helpful. Please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0311OpenMrs. Barbara G. Rothschild, 2134 Springdale Drive, Columbus, GA 31906; Mrs. Barbara G. Rothschild 2134 Springdale Drive Columbus GA 31906; Dear Mrs. Rothschild: This is in response to your letter of January 29, 1971, in which yo inquired whether a particular safety belt system, described in a patent application, would qualify as a 'passive restraint' within the meaning of the Occupant Crash Protection standard. We have delayed an answer to your inquiry, pending issuance of amendments to that standard that were made on March 10, 1971 (36 F.R. 4600), in response to petitions for reconsideration.; You describe your system as one in which 'you have to manually pivo the belt in order to take your seat in the car'. From that point on, however, everything is automatic . . .' The issue, then is whether such a system is a 'means that require[s] no action by vehicle occupants,' in the words of the standard.; Our position is that such a system would not meet the above requiremen of the standard, since it is a system that does require action by the occupant, *i.e.*, pivoting the belt. By 'no action' is meant just that--no action by occupants other than would be required if the protective system were not present in the vehicle. We recognize that in some cases, the action that is required may be relatively slight. In terms of regulatory categories, however, we consider it important to distinguish 'no-action' systems from 'forced-action' systems, of which the most commonly discussed example is the seat belt with an ignition interlock. Your system appears clearly to come within the forced-action category.; Please note that although we are glad to provide interpretations i response to specific questions such as yours, the National Highway Traffic Safety Administration generally does not issue overall 'approvals' of any vehicle or motor vehicle equipment, with respect to conformity with the standards.; Sincerely, Douglas W. Toms, Acting Administrator |
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ID: aiam2402OpenMr. R. L. Ratz, Product Safety Engineer, The Flxible Company, 970 Pittsburgh Drive, Delaware, OH, 43015; Mr. R. L. Ratz Product Safety Engineer The Flxible Company 970 Pittsburgh Drive Delaware OH 43015; Dear Mr. Ratz: This is in reply to your letter of September 7, 1976, to Mr. Dyson formerly of this office, requesting a confirmation that an interpretation of Motor Vehicle Safety Standard No. 108, rendered to the Southern California Rapid Transit District on August 5, 1974, is still valid, and that it can be extended to include identification lamps as well.; In our earlier letter we advised the District that the installation o wiring by a manufacturer enabling a purchaser to connect it to normally steady-burning clearance lamps, enabling them to be flashed to signal a crime in progress would not violate S4.6(b) which requires clearance lamps to be steady-burning, or S4.1.3 that prohibits installation of motor vehicle equipment which impairs the effectiveness of the lighting equipment required by Standard No. 108. This will confirm that that interpretation is still valid.; Your letter, however, raises two additional issues which deserve to b answered for the record. The first is whether the bus manufacturer rather than the purchaser may make the connection, and the second is whether identification lamps may also be included in the warning system. Since it is our opinion that use of the clearance lamps in an emergency mode creates an item of lighting equipment not required by Standard No. 108 and hence outside its coverage, we have concluded that the manufacturer may connect both clearance and identification lamps to the emergency circuit without any resultant nonconformances with S4.6(b) and S4.1.3.; I hope this is responsive to your request. Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4885OpenMr. Takashi Odaira Chief Representative Emission & Safety Isuzu Technical Center of America, Inc. 41050 Vincenti Court Novi, Michigan 48375; Mr. Takashi Odaira Chief Representative Emission & Safety Isuzu Technical Center of America Inc. 41050 Vincenti Court Novi Michigan 48375; "Dear Mr. Odaira: This responds to your letter requesting a interpretation on whether the Isuzu 2-door Coupe is subject to the rear seat requirements set forth in the final rule on Standard No. 214, Side Door Strength, published on October 30, 1990 (55 FR 45722). As noted by your letter, the rear seat requirements do not apply to passenger cars which have rear seating areas that are so small that the SID dummy cannot be accommodated according to the specified positioning procedures. The issues raised by your letter are addressed below. By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment meet applicable standards. The following provides our opinion based on the facts provided in your letter. Your letter describes the positioning of the SID as follows: In this vehicle, when the SID dummy is seated at the rear outboard passenger position according to the specified positioning procedures, the dummy's head comes into contact with the roof and backlight glass which have steep slopes. To avoid the interference, in our test, the head was tilted forward as much as possible and, in addition, the upper torso was also tilted forward, away from the seat back. Only in this way, could we accommodate the dummy in the seating area without changing the orientation of the thorax midsagittal plane, or affecting the H-point. You noted, however, that '(t)his condition . . . obviously does not meet the positioning procedure of paragraphs S7.l.3(a) and (b), which provides, 'The upper torso of the test dummy rests against the seat back.'' You stated that it is therefore your interpretation that the vehicle cannot accommodate the SID dummy and that the rear seat requirements are not applicable to it. You requested our views regarding your understanding. In the preamble to the October 1990 final rule, NHTSA noted that, for some vehicles where the roof has a steep rear slope, the SID head can be tilted so as to accommodate the test dummy without changing the specified orientation of the thorax midsagittal plane or affecting the H-point (two of the specifications in the S7 positioning procedure). The agency also noted that there are some cars with rear seating areas that are so small that the SID dummy cannot be accommodated according to the specified positioning procedures, even if the head is adjusted fore-aft. Section S3 of Standard No. 214 provides that the rear seat requirements do not apply to 'passenger cars which have rear seating areas that are so small that the SID dummies cannot be accommodated according to the positioning procedure specified in S7.' Thus, if any aspect of the positioning procedure, including the specification that the upper torso rests against the seat back, cannot be met, the vehicle is not required to meet the rear seat requirements of Standard No. 214. With regard to whether the Isuzu 2-door Coupe is subject to Standard No. 214's rear seat requirements, NHTSA cannot make a determination that the rear seat requirements do not apply to a vehicle based solely on a description and photographs of that test procedure. If the agency should conduct a compliance test for the vehicle, it would attempt to position the SID dummies in the rear seat according to the specified seating procedure. If NHTSA were unable to position SID dummies in the rear of the vehicle according to the specified procedure, it would conclude that the rear seat requirements do not apply to that particular vehicle. I hope you find this information helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam2052OpenMr. John B. White, Engineering Manager, Technical Information Department, Michelin Tire Corporation, P.O. Box 3467, New Hyde Park P.O., New York 11040; Mr. John B. White Engineering Manager Technical Information Department Michelin Tire Corporation P.O. Box 3467 New Hyde Park P.O. New York 11040; Dear Mr. White: This is in reply to your letter of July 9, 1975, inquiring as to th proper designation of plies on a truck tire constructed with two polyamide plies in the casing and two steel plies in the belt.; The designation that you suggested ('Tread: 2 Steel Plies, Sidewall: Polyamide Plies') is incorrect. The designation on such a tire should indicate the presence of four plies in the tread area and two in the sidewall area (with compositions in each case).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0595OpenMr. Victor Wouk, Chairman, Technical Advisory Committee, Electric Vehicle Council, Edison Electric Institute, Petro- Electric Motors, Ltd., 342 Madison Avenue, New York, NY 10017; Mr. Victor Wouk Chairman Technical Advisory Committee Electric Vehicle Council Edison Electric Institute Petro- Electric Motors Ltd. 342 Madison Avenue New York NY 10017; Dear Mr. Wouk:#This is in further response to your letter of Decembe 16, 1971, requesting interpretations of several Federal motor vehicle safety standards as they apply to electric vehicles.#The engine retardation braking effect of Standard No. 102 applies only to vehicles equipped with automatic transmission, and not to an electric vehicle that has no transmission.#Standards Nos. 201 through 204 do not apply to trucks. You have stated that your electric vehicle is designed to that 'the rear . . . will normally be used for tools, service equipment, spare parts, etc., as would be required in a service vehicle as used by an electric utility company for going out and making repairs.' You have also stated that the back area could be converted to a seating area for two passengers, but that this would be 'unusual and occasional.' On the basis of this information we have concluded that you vehicle is a 'truck' and need not meet Standards Nos. 201-204.#Sincerely, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam3213OpenMr. Glenn Brinks, 2110 Magnolia Avenue, Santa Ana, CA 92707; Mr. Glenn Brinks 2110 Magnolia Avenue Santa Ana CA 92707; Dear Mr. Brinks: This is in further reply to your earlier questions concerning Federa requirements for fuel systems on motorcycles. As stated in our previous letter, Federal Motor Vehicle Safety Standard No. 301-75, *Fuel System Integrity* (49 CFR 571.301-75), does not apply to motorcycles. You are correct in your assumption that there are no Federal regulations that would preclude the use of fiberglass fuel tanks for motorcycles. I might add that Safety Standard No. 301-75 does not specify design requirements for any vehicles (e.g., that the tank be made of metal or any particular material). Rather, the standard specifies performance levels that the entire fuel system must achieve during barrier crash tests.; Although no safety standards or other regulations preclude the use o fiberglass fuel tanks for motorcycles, you should still be responsible for assuring that such tanks are safe. Under the National Traffic and Motor Vehicle Safety Act, amended 1974, a manufacturer of motor vehicles or motor vehicle equipment is responsible for any defect relating to motor vehicle safety which may exist in the manufacturer's product (15 U.S.C. 1411, *et seq*.). The manufacturer would be required to notify all purchasers of the existence of the defect and to remedy the defect at the manufacturer's expense.; I might point out that the agency is concerned that fiberglass fue tanks will shatter upon impact in a collision, rather than crushing as do metal tanks. If you have any crash data regarding the performance of fiberglass motorcycle fuel tanks, we would appreciate receiving the information.; I hope this has answered all your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2951OpenMr. Hisakazu Murakami, Staff, Safety, Nissan Motor Co., Ltd., P.O. Box 1606, 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Hisakazu Murakami Staff Safety Nissan Motor Co. Ltd. P.O. Box 1606 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Murakami: This responds to your January 9, 1979, letter concerning a mistake o the certification labels of approximately 2000 Datsun trucks. You stated that the vehicles, although manufactured in 1979, were incorrectly dated on their certification labels as being manufactured in 1978. You propose to remedy the affected vehicles by crossing out the incorrect date and inserting the correct information.; Your proposed correction is acceptable to the National Highway Traffi Safety Administration. As long as all other information on the certification label is correct, your modification of existing certification labels will comply with the agency's regulations.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3643OpenMr. Masakatsu Kano, Executive Vice President, MMC Services Inc., 3000 Town Center, Suite 1960, Southfield, MI 48075; Mr. Masakatsu Kano Executive Vice President MMC Services Inc. 3000 Town Center Suite 1960 Southfield MI 48075; Dear Mr. Kano: This responds to your letter of April 20, 1983, asking severa questions concerning the requirements for armrests in Safety Standard No. 201, *Occupant Protection in Interior Impact*. That standard requires, as one optional means of compliance (S3.5.1(c)), that each armrest have at least 2 inches of coverage within the pelvic impact area, when measured vertically in side elevation. You ask whether this 2-inch measurement may be made from the outermost points of the base of the armrest as it fits against the door inner trim, or whether the measurement must be made from the inboard portion of the armrest that would actually contact a vehicle occupant. You also ask if the standard permits an armrest surface that would contact an occupant to be tilted at a 15 degree angle from the vertical, and whether it permits that surface to have 'low moles' or 'shallow bezels' (i.e., minor protrusions or indentations).; With reference to the drawing included in your letter, Standard No. 20 would require the specified 2-inch measurement to be taken at the 'H1' parameters, rather than the 'HO'. The purpose of the requirement is to ensure that there is at least 2 inches of coverage within the pelvic impact area. For this requirement to be meaningful, the covered surface must be contactable by the vehicle occupant. The vehicle occupant would not contact the base of the armrest illustrated in your drawing, regardless of its vertical length.; Paragraph S3.5.1(c) does not preclude 'moles' or 'bezels' in th armrest, since there are no limitations on radius of curvature. A 'mole' which projected only moderately into the vehicle interior would be included in the calculation to determine compliance with the requirement for 2 inches of covered surface. If a mole projected so far into the vehicle interior that it would prevent pelvic contact with the rest of the armrest, however, only the mole would be included in the calculation.; By the same token, while a 'bezel' is not precluded, it is not include in the calculation if it is so deep that it cannot be contacted.; Paragraph S3.5.1(c) does not specify any particular angle at which a armrest must be set with relation to the door inner trim. Therefore, it is permissible for the inboard surface of the armrest illustrated in your drawing to make an angle of 15 degrees from the vertical.; Finally, I would point out that paragraph S3.5.1(c) is one of thre optional means of compliance for manufacturers who install armrests. A manufacturer may also satisfy the requirements of Standard No. 201 by complying with either S3.5.1(a) or S3.5.1(b), in which case it is not necessary to provide 2 inches of coverage within the pelvic impact area.; Sincerely, Frank Berndt, 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.