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: aiam0092OpenMr. Toyotaro Yamada, Manager, Toyota Motor Company, Ltd., 231 Johnson Avenue, Newark, NJ 07108; Mr. Toyotaro Yamada Manager Toyota Motor Company Ltd. 231 Johnson Avenue Newark NJ 07108; Dear Mr. Yamada: Thank you for your letter of June 27, 1968, in which you requeste clarification of the term 'optically combined' as applied to motor vehicle lights.; 'Optically combined' in this context means that the same lens area i used for more than one function such as tail and stop lights or stop and turn signal lights or tail, stop and turn signal lights. The normal means used to accomplish this 'optically combined' lamp has been to incorporate a single dual-filament bulb with a reflector and lens.; Since the design of your Toyata (sic) Crown combination stop, tail an turn signal lamp is such that a different part of the lens area is used for the turn signal lamp, we do not interpret it to be optically combined with the tail and stop lamp.; The concurrence of the above interpretation with yours and that of th California Highway Patrol should not be construed to be an approval of your design. The results of recent research on lighting and signaling reviewed by this Bureau indicate that signal lights should be separated 4 1/2 to 5 inches minimum (centerline to centerline separation.) Although no dimensions are specified on your drawing it appears to be approximately full scale with a separation distance of 2 1/4 inches between the stop and turn signal lamps. The steady-burning stop lamp may therefore 'wash out' or significantly reduce the effectiveness on the turn signal lamp. Federal Motor Vehicle Safety Standard 108 does not require a minimum separation distance between signal lights, however, upon completion of our present research contracts on rear lighting and signaling, we may consider such a requirement in the future.; Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam5290OpenMr. Jerome Cysewski 1404 Lewis Avenue Billings, MT 59102; Mr. Jerome Cysewski 1404 Lewis Avenue Billings MT 59102; Dear Mr. Cysewski: This responds to your letter asking about th applicability of Federal requirements to two vehicles. I apologize for the delay in our response. According to your letter, one vehicle is a 13,600 pound cement silo that has tandem axles. The second vehicle is a 6,400 pound aggregate batch plant that has a single axle. The cement silo and batch plant are mounted on their own trailers, and are equipped with electric brakes. Each vehicle is pulled by a one ton truck with hydraulic brakes. You also stated that both vehicles are mobile but are designed to be towed for off-the-road set and positioning. I am pleased to have this opportunity to explain our regulations to you. By way of background information, this agency, the National Highway Traffic Safety Administration (NHTSA), issues Federal motor vehicle safety standards under the National Traffic and Motor Vehicle Safety Act (Safety Act). The Safety Act defines the term 'motor vehicle' as follows: 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.' (Section 102(3)) If a vehicle is a motor vehicle under the definition, then the vehicle must comply with all applicable Federal motor vehicle safety standards. However, if a vehicle is not a motor vehicle under this definition, then the vehicle need not comply with the agency's safety standards because such a vehicle is outside the agency's scope of authority. Whether NHTSA considers a construction vehicle, or similar equipment, to be a motor vehicle depends on the use for which it is manufactured. It is the agency's position that this statutory definition does not encompass mobile construction equipment, such as cranes and scrapers, which use the highway only to move between job sites and which typically spend extended periods of time at a single job site. In such cases, the on-highway use of the vehicle is merely incidental and is not the primary purpose for which the vehicle was manufactured. In instances where vehicles, such as dump trucks, frequently use the highway going to and from job sites, and stay at a job site for only a limited time, such vehicles are considered motor vehicles for purposes of the Safety Act, since the on-highway use is more than 'incidental.' Your letter does not provide sufficient information for us to determine the extent to which the two vehicles would use the public roads. Nor can we determine whether the on-highway use of the vehicles would be merely incidental and not the primary purpose for which they are manufactured. However, you should be able to determine whether the vehicles are considered motor vehicles based on the information set forth above. If the vehicles are considered motor vehicles under the Safety Act, they would be required to meet all safety standards applicable to trailers. Enclosed is an information sheet which identifies Federal statutes and NHTSA standards and regulations affecting motor vehicle and motor vehicle equipment manufacturers. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam0568OpenMr. K. Nakajima, Director/General Manager, Toyota Motor Company, Ltd., Lyndhurst Office Park, 1099 Wall Street West, Lyndhurst, NJ 07071; Mr. K. Nakajima Director/General Manager Toyota Motor Company Ltd. Lyndhurst Office Park 1099 Wall Street West Lyndhurst NJ 07071; Dear Mr. Nakajima: This letter is in response to your inquiry of January 6, 1972 regarding the relationship of Standards No.208 and No.216.; You interpret Standard 216, paragraph *S3. Application*, which state that the Standard does not apply to passenger cars 'that conform to the rollover test requirements (S5.3) of Standard 208 by means that require no action by vehicle occupants,' as follows:; >>>1. From August 15, 1973, the effective date of Standard 216, t August 15, 1977, passenger cars are not required to meet Standard 216 if they conform to the 'first option' of Standard 208.; 2. For the period of August 15, 1973, through August 14, 1975 passenger cars which are designed to conform to the 'second' or proposed 'third' option of Standard 208 are not required to meet Standard 216 if they meet the rollover requirements (S5.3) by passive means (when tested under the applicable conditions of S8), even though in Standard 208 the rollover requirement is specified only for 'option 1.'<<<; These interpretations are correct. Please write if we can be of furthe assistance.; Sincerely yours, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2555OpenMiss Irene Glessner, 276 Birch Avenue, Elsmere Manor, Wilmington, DE 19805; Miss Irene Glessner 276 Birch Avenue Elsmere Manor Wilmington DE 19805; Dear Miss Glessner: This responds to your March 21, 1977, letter asking whether a tir dealer is required to record the serial numbers of the tires he sells.; The National Highway Traffic Safety Administration (NHTSA) promulgate regulations pertaining to tires. One of these regulations, Part 574, *Tire Identification and Recordkeeping*, requires tire dealers and distributors to obtain information when the tire is sold and to forward that information to the tire manufacturer. I am enclosing a copy of this regulation for your information. In S574.7 of the regulation you will find the exact information for which a tire dealer is responsible.; A tire dealer would not be responsible for the ultimate recall o tires. The information which a dealer submits to a manufacturer enables the manufacturer to undertake recalls. Failure to record and submit the information to a manufacturer would be a violation of Section 108 of the National Traffic and Motor Vehicle Safety Act of 1966 (as amended) (15 U.S.C. 1381, 1397). Each violation is punishable by a civil penalty of $1,000 up to a maximum of $800,000 for a series of violations (15 U.S.C. 1398).; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2806OpenDr. Arthur Yeager, 1 Park Place, Westwood, NJ 07675; Dr. Arthur Yeager 1 Park Place Westwood NJ 07675; Dear Dr. Yeager: This responds to your telephone request of March 24, 1978, askin whether the seats in school buses are sufficiently strong to allow the installation of seat belts. You stated that some manufacturers are indicating that they cannot install seat belts because the floors of larger school buses cannot withstand the forces generated by seat belts.; As you indicated, Notice 5 of Docket 73-3 stated that school bus seat should be strong enough to withstand the forces seat belts would impose upon them. This statement was based upon the fact that the seats would be designed to comply with the other force requirements of the standard which would increase the strength of the seats making them capable of withstanding seat belt loads. At the time of that notice, there were special seat belt requirements for seat belts in school buses in the then proposed Standard No. 222. These seat belt requirements would have mandated lower belt load requirements than those found in Standard No. 210 which currently applies to school buses (under 10,000 pounds GVWR). The seats in larger school buses should be sufficiently strong to withstand the former proposed force requirements of Standard No. 222, but they might be incapable of withstanding the belt load requirements of Standard No. 210.; Manufacturers who indicate that the seats or floors of larger buses ar not strong enough to install seat belts probably misunderstood the belt requirements for large buses. Seat belts can be installed for passenger seats in larger school buses without complying with any existing seat belt requirements. Seat belts for passenger seats are not required, for example, to comply with Standard No. 210. Therefore, a State would be permitted to establish their own acceptable belt load requirements for these seat belts in large school buses. The National Highway Traffic Safety Administration suggests that States adopt the belt load requirements previously proposed for Standard No. 222. School bus seats currently in production should be sufficiently strong to withstand the former proposed belt load requirements.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3714OpenMr. Louis Gaia, V.P. Purchasing, Ezon Products, Inc., P.O. Box 18134, Memphis, TN 38118; Mr. Louis Gaia V.P. Purchasing Ezon Products Inc. P.O. Box 18134 Memphis TN 38118; Dear Mr. Gaia: In your letter of June 2, 1983, to the Office of Chief Counsel, yo asked if there were 'any D.O.T. requirements on miniature bulbs?'; We understand your question to refer to bulbs used in lighting device other than headlamps. Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*, imposes no performance requirements on individual bulbs used in lighting devices other than those used in replaceable bulb headlamps (an option permissible as of July 1, 1983). Other lighting devices must meet the photometric requirements of the standard with the bulb, chosen by the lighting device manufacturer, installed.; I hope that this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1729OpenHonorable Birch Bayh, United States Senate, Washington, DC 20510; Honorable Birch Bayh United States Senate Washington DC 20510; Dear Senator Bayh: This is in response to your letter requesting information concernin correspondence from Mr. James A. Graham, commenting on a proposed amendment to the Federal bumper standard.; On January 2, 1975, the National Highway Traffic Safety Administratio (NHTSA) issued a *Federal Register* notice (copy enclosed) proposing to reduce the current 5-mph bumper impact requirements to 2.5 mph until the 1979 model year. The impact requirements would have been increased to 4 mph for 1979 and later model year cars.; The proposal was based primarily on the results of two agency-sponsore studies which indicated that the cost and weight of many current production bumpers, in light of inflation and fuel shortages, made the bumpers no longer cost beneficial. Information presented at public hearings on the bumper notice and comments submitted to the docket in response to the proposal have brought to light additional data. The NHTSA has carefully examined all of this evidence and reviewed its studies in light of the new information. As a result, the agency has concluded that the 5-mph protection level should not be reduced. This decision is contained in a *Federal Register* notice that was published March 12, 1975, which is enclosed (Docket No. 74-11, Notice 7, Docket No. 73-19, Notice 6).; In his letter Mr. Graham objects to the standard's regulation o surface damage, such as dents, stating that this is not the type of damage which should be addressed by an agency developing safety standards. The surface damage criteria are proposed as part of a standard being promulgated under Title I of the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513). The Cost Savings Act directs the National Highway Traffic Safety Administration to develop a bumper standard that will obtain the maximum feasible reduction of costs to the public and the consumer. As such, the standard is not to be limited to affecting safety- related damage. Factors such as insurance costs and consumer time and inconvenience are to be considered in the rulemaking as well.; Mr. Graham's comments will be placed in the public docket where the will receive every consideration.; We appreciate your interest and that of Mr. Graham in this area o motor vehicle safety and performance.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam0991OpenMr. Satoshi Nishibori, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Satoshi Nishibori Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letter of January 23, 1973, concerning th sequence of manual switch operation under S7.4.4 of Motor Vehicle Safety Standard No. 208. Your question is whether S7.4.4 requires the manual switch and ignition switch to be operated in a specific order.; S7.4.4 does no require any specific sequence. After the ignition ha been turned off, it can be made operable either by turning the ignition switch on, then operating the manual switch, of by operating the manual switch and then turning the ignition on.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1683OpenMr. Jeffrey B. Lugash, Suite 2200, 1801 Century Park East, Los Angeles, California 90067; Mr. Jeffrey B. Lugash Suite 2200 1801 Century Park East Los Angeles California 90067; Dear Mr. Lugash: This responds to your October 30, 1974, questions whether th Department of Transportation or any 'private establishment' requires manufacturers to file specifications for automobile, motorcycle, and airplane tires, whether Standard No. 119, *New pneumatic tires for vehicles other than passenger cars*, lists these specifications, and what the number '222474 7MRR' means on the bead of a motorcycle tire.; The Department of Transportation's National Highway Traffic Safet Administration has issued Standard No. 119 (effective March 1, 1975), which establishes minimum performance and labeling requirements with which the manufacturer must comply. A copy of the standard is enclosed. Certain tire specifications must appear on the sidewall, and certain rim-matching specifications must be published by the manufacturer or appear in a publication of at least one private tire organization.; It is the general practice of the tire industry to list specification of tires in a private publication, such as the 'Year Book' of the Tire and Rim Association in the United States. Their address is: The tire and Rim Association, Inc., 3200 West Market Street, Akron, Ohio 44313.; The NHTSA Tire and Wheel Division has determined that the number whic you cite is of significance only to the manufacturer of the tire.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3344OpenMr. R. H. Madison, Engineering Consultant, 12814 Ashbury Drive, Tantallon, MD 20022; Mr. R. H. Madison Engineering Consultant 12814 Ashbury Drive Tantallon MD 20022; Dear Mr. Madison: This responds to your June 25, 1980, letter asking whether a propose air brake system that you submitted would comply with the requirements of Standard No. 121, *Air Brake Systems*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approval of systems constructed in compliance with safety standards. It is the responsibility of manufacturers to assure that their vehicles or equipment comply with the requirements of the safety standards. It is frequently impossible for the agency to tell from diagrams and descriptions of devices whether they will comply with the standards. Compliance is based upon testing and observation of the entire vehicle or piece of equipment as it is installed on the vehicle. Without the benefits of such tests, NHTSA cannot state whether your system would comply with Standard No. 121.; Our engineering staff has reviewed your letter and offers the followin information. First, the standard contains no requirements for tractor protection valve control pressures. However, control pressures are usually set so that the trailer brakes apply before the tractor brakes.; Second, you asked whether it is appropriate to require the release o parking brakes by pushing in both the tractor protection control valve and the park valve. The standard states that the parking brake control shall control the parking brakes of the vehicle and any vehicle it is designed to tow. The standard is silent regarding the release of those brakes.; Sincerely, Frank Berndt, Chief Counsel |
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.