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: aiam2968OpenMr. James Tydings, Thomas Built Buses, Inc., 1408 Courtesy Road, P.O. Box 2450, High Point, NC 27261; Mr. James Tydings Thomas Built Buses Inc. 1408 Courtesy Road P.O. Box 2450 High Point NC 27261; Dear Mr. Tydings: This responds to your February 28, 1979, letter asking about th remanufacturing of vehicles using old chassis and new bodies. In particular, you ask whether these vehicles must comply with the new safety standards.; The remanufacturing operation that you mention need not comply with th new safety standards. Such a remanufactured vehicle may need to comply with the safety standards in effect on the date of manufacture of the used chassis. Otherwise, there might be a rendering inoperative of the compliance of the vehicle with the safety standards. I am enclosing a copy of an interpretation that discusses the remanufacturing issue.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1647OpenMr. R. W. Schneider, Director, Contract Administration, AM General Corporation, 701 West Chippewa Avenue, South Bend, IN 46623; Mr. R. W. Schneider Director Contract Administration AM General Corporation 701 West Chippewa Avenue South Bend IN 46623; Dear Mr. Schneider: This is in reference to your defect notification campaign (NHTSA No 74-0168) concerning some 1/4-ton Model DJ-5C vehicles which may have insufficient windshield glass retention.; The letter which you have sent to the owners of the subject vehicle does not contain the precise language which is required by Part 577 (49 CFR), the Defect Notification regulation. Specifically, the second sentence of your letter incorrectly describes the defect as existing in 'the retention of the front windshield on the 1/4-ton Model DJ-5C 'Jeep' Dispatcher. . . .' Part 577.4(b) requires that the defect be described only as existing in the vehicle. The reference to motor vehicle equipment applies only to equipment campaigns where vehicles are not involved. The letter also fails to adequately evaluate the risk to traffic safety as required by Part 577.4(d).; Although mailing of a revised notification letter will not be required it is expected that all future notification letters conform completely with the regulations.; A copy of Part 577 is enclosed. If you desire further information please contact Messrs. W. Reinhart or James Murray of this office at (202) 426-2840.; Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam3380OpenMr. Eric C. Oppenheim, Esq., Corporate Attorney, Kux Manufacturing Company, 12675 Burt Road, Detroit, MI =48223; Mr. Eric C. Oppenheim Esq. Corporate Attorney Kux Manufacturing Company 12675 Burt Road Detroit MI =48223; Dear Mr. Oppenheim: This is in reply to your letter of November 23, 1980 asking whether an Federal regulation 'prohibits the use of reflective red markings on the front of vehicles.'; The Federal Motor Carrier Safety Regulation administered by the Federa Highway Administration of the Department of Transportation impliedly prohibit the use of red reflectors on the front of vehicles subject to its jurisdiction by requiring that all reflectors, other than those at the rear, be amber in color (49 CFR 393.26(d)). The common contract, private or exempt carriers covered by this requirement are found in 49 U.S.C. 303.; The Federal motor vehicle safety standard on vehicle lighting (49 CF 571.108) applicable to the manufacture of all motor vehicles contains a general prohibition (paragraph S4.1.3) against installation of reflective devices that impair the effectiveness of required lighting equipment. Because of the generally accepted lighting coding of amber to the front and red to the rear, we would view installation of red reflective material on the front of a vehicle as prohibited by S4.1.3.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4445OpenMr. Billy S. Peterson President Automotive Safety Testing, Inc. Product Liability-Testing-Certification at TRC of Ohio East Liberty, OH 43319; Mr. Billy S. Peterson President Automotive Safety Testing Inc. Product Liability-Testing-Certification at TRC of Ohio East Liberty OH 43319; Dear Mr. Peterson: This is in reply to your letter of September 23 1987, with respect to positioning of rear mounted lamps and reflectors in accordance with Federal Motor Vehicle Safety Standard No. 108. Your client has designed a vehicle in which the backup lamps and rear reflex reflectors would be mounted on the deck lid, and you have asked whether there are any current or contemplated prohibitions that would preclude this design. The lamps in question will be mounted on a rigid part of the vehicle as required by paragraph S4.3.1 of Standard No. 108, and the deck lid will be closed and the lamps and reflectors in full view under normal operating conditions. The visibility requirements of lamps and reflectors in Standard No. 108 are predicated on the normal driving or closed deck lid position. Since the use of motor vehicles, including driving with deck lids open or otherwise having the lamps and reflectors obscured by a particular load on the vehicle is under the jurisdiction of the individual States, we do not anticipate rulemaking on this subject. Thus this design is not prohibited by Standard No. 108. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam0406OpenMr. David J. Humphreys, Washington Counsel, Recreational Vehicle Institute, Inc., Suite 406, 1140 Connecticut AVenue, Washington, DC 20006; Mr. David J. Humphreys Washington Counsel Recreational Vehicle Institute Inc. Suite 406 1140 Connecticut AVenue Washington DC 20006; Dear Mr. Humphreys: This is in reply to your letter of June 22, 1971, enclosing a copy o Mr. Shrake's memorandum 'Seat Belts Required by July 1, 1971', copy attached.; We concur in your conclusion that the seat belt requirement does no apply to chassis-cabs, cabs, and vans, manufactured before July 1, 1971, and that, on or subsequent to that date, are completed as, or modified to become, motor homes. We concur also with the other points set out in the memorandum.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam4916OpenMr. Michael D. Incorvaia Manufacturing Engineering Manager Wagner Lighting P.O. Box 4650 Sevierville, TN 37864; Mr. Michael D. Incorvaia Manufacturing Engineering Manager Wagner Lighting P.O. Box 4650 Sevierville TN 37864; Dear Mr. Incorvaia: This responds further to your letter of July 3 1991, which we informed you on August 20, will be accorded confidential treatment. Paragraph 4.5 of SAE Standard J588e, Turn Signal Lamps, September 1970, states that 'failure of one or more turn signal lamps to operate should be indicated by a 'steady on', 'steady off', or by a significant change in the flashing rate of the illuminated indicator.' Electronic flashers available today provide a 'significant change' in flash rate by doubling it as an outage indication. Wagner Lighting has developed a lamp outage indication that will remain within the performance parameters of Standard No. 108, but provide an outage flash rate that appears to be slightly less than 50% greater than that of normal operation. However, there will be 'a recognized change in flashing rate.' You have asked whether these changes may be regarded as 'significant' within the meaning of SAE J588e. Your letter indicates that the design contemplated by Wagner Electric is for application in new motor vehicles. Although SAE J588e remains in effect as a replacement equipment standard, Standard No. 108 has been amended to incorporate by reference new SAE standards for turn signal lamps, and it is these standards that now apply to turn signals on new motor vehicles. Specifically, on and after December 1, l990, a motor vehicle must be manufactured to meet either SAE Standard J588 NOV84, Turn Signal Lamps for Use on Motor Vehicles Less Than 2032 mm in Overall Width, or SAE Standard J1395 APR85, Turn Signal Lamps for Use on Motor Vehicles 2032 mm or More in Overall Width. The outage indication requirement of SAE J588e was not adopted in either of the SAE standards, and has not been incorporated directly in Standard No. 108. This means that outage indication is no longer a requirement on new motor vehicles, and that Wagner Electric, under Standard No. 108, may adopt such change in flash rate as its design may call for. We are returning the tape that you enclosed. Sincerely, Paul Jackson Rice Chief Counsel Enclosure; |
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ID: aiam5604OpenMs. Yvonne Anderson Todd Vans East Highway 28 Morris, MN 56267; Ms. Yvonne Anderson Todd Vans East Highway 28 Morris MN 56267; "Dear Ms. Anderson: This responds to your letter of July 13, 1995 concerning a van which your company is modifying. The van is owned by a local school system. The school system has asked your company to raise the roof, extend the side door, install wheelchair tiedowns, and install a wheelchair lift. The vehicle was certified as a 'bus,' but your modification would reduce the seating capacity so that the vehicle would become a 'multipurpose passenger vehicle' (MPV). You asked whether this vehicle must be certified following the modifications. The answer to your question is no. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards that apply to the manufacture and sale of new motor vehicles. A vehicle must be certified as complying with all applicable safety standards before it can be sold or imported. After the first retail sale, there is a limit on modifications made to vehicles. Manufacturers, distributors, dealers, and repair businesses are prohibited from 'knowingly making inoperative' any device or element of design installed on or in a motor vehicle in compliance with an applicable safety standard (49 USC 30122). In general, the 'make inoperative' prohibition would require a business which modifies motor vehicles to ensure that they do not remove, disconnect, or degrade the performance of safety equipment installed in compliance with an applicable safety standard. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0056OpenMr. David A. Phelps, Jr., Engineering Services, Blue Bird Body Company, Fort Valley, GA 31030; Mr. David A. Phelps Jr. Engineering Services Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Phelps: Thank you for your letter of March 19, 1968, to Mr. George C. Nield requesting a clarification of paragraphs S3.4.4 and S3.4.4.1 of Motor Vehicle Safety Standard No. 108.; In your letter you listed possible brake combinations as follows:>>>1 A vacuum over dual hydraulic brake system and a hand operated mechanical brake are provided.; 2. A full air brake system and a hand operated mechanical brake ar provided.; 3. A full air brake system with a spring loaded emergency stoppin system which is actuated at a pre-determined low air pressure level and a hand operated mechanical brake are provided.<<<; In accordance with the interpretation issued February 27, 1967, (3 F.R. 3390, copy enclosed), on 'emergency brakes,' the supplementary brake systems included in the above brake combinations are not emergency brakes. Therefore, paragraph S3.4.4 of Standard No. 108 does not require that the stop lamp be actuated upon application of these supplementary brakes.; Thank you for writing. Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam5254OpenMr. Tom DeLapp Executive Coach Builders, Inc. One Executive Blvd. Springfield, MO 65802; Mr. Tom DeLapp Executive Coach Builders Inc. One Executive Blvd. Springfield MO 65802; Dear Mr. DeLapp: This responds to your letter of August 18, 1993 concerning a modification you wish to make on limousines manufactured by your company. You wish to modify the hinge assembly controlling forward and reclining movement of the front seat to provide access to the area between the front of the privacy panel and the back of the front seat. (The area contains auxiliary fuse panels and relays.) The modification would involve removal of a metal pin in the hinge assembly, allowing the seat to articulate forward to a greater degree. You asked whether Standard No. 207, Seating Systems, prohibits the removal of a limiting pin or limits forward movement of a seat back. Standard No. 207 specifies strength and other performance requirements for seats in passenger cars, multipurpose passenger vehicles, trucks, and buses. Section S4.3 of Standard No. 207 contains requirements for hinged or folding seat backs, except for passenger seats in buses or a seat adjustable only for its occupants. Section S4.3(a) requires a self-locking device for restraining the hinged or folding seat back. Section S4.3.2 contains performance requirements for this restraining device. Section S4.3 does not limit the degree of movement of a hinged or folding seat back. Thus, you may remove the limiting pin if removing it only increases the degree of movement of the seat. However, the seat must still meet the requirements of S4.3 with the pin removed. Accordingly, the seat must have a self-locking device that can withstand the force applications specified in S4.3.2.1 and acceleration specified in S4.3.2.2. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2591OpenMr. Thomas E. Niehaus, 329 Miller Court, Harrison OH 45030; Mr. Thomas E. Niehaus 329 Miller Court Harrison OH 45030; Dear Mr. Niehaus: This is in response to your letter of May 2, 1977, asking whethe Federal requirements specify that motor vehicle bumpers must be equipped with a rubber stripping.; Standard No. 215, *Exterior Protection*, is a motor vehicle safet standard promulgated by the National Highway Traffic Safety Administration. That standard requires that passenger cars be capable of undergoing 5 mph front and rear impacts without incurring damage to certain specified safety systems. Motor vehicle manufacturers are permitted to meet the performance level prescribed by Standard 215 in whatever manner they choose. Most, however, have elected to meet the requirements by improving the strength of the vehicle bumper system. Although a rubber bumper strip is not specifically required by the standard, a manufacturer may use such a component as a means of meeting the prescribed performance level.; All 1977 model year cars must be capable of meeting the requirements o Standard 215. This includes those which are equipped with an optional bumper system and those which are not.; If we can provide you with any further information, please let us know. Sincerely, Joseph J. Levin, Jr., 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.