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: aiam1519OpenMr. John W. Kourik, Chief Engineer, Automotive Products, Wagner Electric Corporation, 6400 Plymouth Avenue, St. Louis, MO 63133; Mr. John W. Kourik Chief Engineer Automotive Products Wagner Electric Corporation 6400 Plymouth Avenue St. Louis MO 63133; Dear Mr. Kourik: This responds to your May 7, 1974, request to know whether check valve or equivalent devices must be placed immediately adjacent to or within each service reservoir in a trailer air brake system to comply with S4.2.1.5 of Standard No. 121, *Air brake systems*, and whether the standard intends each axle subsystem to have a separate service reservoir and check valve system, with particular regard to arrangements for liftable axle systems. S5.2.1.5 states:; >>>S5.2.1.5 Each service reservoir shall be protected against loss o air pressure due to failure or leakage in the system between the service reservoir and its source of air pressure by check valves or equivalent devices.<<<; The answer to both of these questions is no. In an April 3, 1974 letter to Great Dane Trailers, Inc., we interpreted S5.2.1.5 to permit location of the check valve at the isolated reservoir, permitting that valve to also guard the service reservoirs on that axle system. The language of S5.2.1.5 is unclear in this regard, and may be amended in the future. In response to your specific question, it is permissible to use a single check valve to protect more than one reservoir in a subsystem.; Standard No. 121 does not require a separate service reservoir chec valve for each axle system in a tandem axle. As you point out this could decrease total vehicle reliability, and abuse in this area could lead to amendment of the provision. In answer to your fourth question, a single check valve could be utilized to protect the air reservoir or reservoirs required for a liftable axle system or subsystem.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3031OpenMr. 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 May 21, 1979, letter concerning the markin requirements for vehicle windshields having shade bands. You asked whether the 'A S1' marking symbol required by Safety Standard No. 205, *Glazing Materials*, can be placed on the tint band itself rather than on the glazing material below the band, if the tint band is a flexible sheet applied on top of the glazing.; Safety Standard No. 205 incorporates by reference the American Nationa Standard 'Safety Code for Safety Glazing Materials', ANS Z26. The ANS Z26 standard requires special additional markings for glazing that has shade bands or tinted areas:; >>>'Glazing materials, which in a single sheet of material, ar intentionally made with an area having a luminous transmittance of not less than 70 percent (Test NO. 2), adjoining an area which has less than 70-percent luminous transmittance, shall be permanently marked at the edge of the sheet to show the limits of the area which is intended to comply with Test No. 2. The markings shall be A S1 or A S2, etc., the direction of the arrow indicating the portion of the material which complies with Test No. 2 and the number indicating the item with which that portion of the sheet complies ....'<<<; You will note from the quoted portion of this specification that th special marking is only required if the tinted shade band area of the windshield has a luminous transmittance of less than 70 percent. Your letter states that the transparent windshield tint band that you intend to use allows 70 percent light transmission. Therefore, you would not be required to use the 'A S1' special marking either on the band itself or on the glazing.; For removable tint bands of this type that do not have a 70 percen light transmission, however, the agency would permit the 'A S1' marking to be on the tint band itself rather than on the underlying glazing, provided the marking is located at the lowest possible portion of the tint band.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3461OpenMr. Brian Gill, Manager, Certification Department, American Honda Motor Co., Inc., P.O. Box 50, 100 W. Alondra Blvd., Gardena, California 90247; Mr. Brian Gill Manager Certification Department American Honda Motor Co. Inc. P.O. Box 50 100 W. Alondra Blvd. Gardena California 90247; Dear Mr. Gill: This responds to your letter of July 27, 1981, asking about Federa Motor Vehicle Safety Standard No. 101-80. Your letter asked whether an enclosed sample of a heater control identification plate met the requirements of section S5.2.2 of the standard. Your letter was primarily concerned about whether the color used for the hot extreme would be considered 'red' within the meaning of that section.; The sample heater control identification plate enclosed with you letter identifies the hot an cold extremes of the temperature control by both words and color. At the left of the identification plate is the word 'cold' on a blue background. At the right of the identification plate is the word 'hot' on a background that appears by visual inspection to be orange.; Section S5.2.2 of Standard No. 101-80 states: >>>Identification shall be provided for each function of any automati vehicle speed system control an any heating and air conditioning system control, and for the extreme positions of any such control that regulates a function over a quantitative range. If this identification is not specified in Tables 1 or 2, it *shall be in word form unless color coding is used*. If color coding is used to identify the extreme positions of a temperature control, the hot extreme shall be identified by the color red and the cold extreme by the color blue . . . . [Emphasis added.]<<<; The agency interprets section S5.2.2 to require that the colors red an blue be used to identify the extreme positions of a temperature control only when color is the sole means by which the extreme positions are identified. If the words 'hot' and 'cold' are used to identify the extreme positions, color coding is a voluntary addition and the red and blue color requirements of section S5.2.2 do not apply.; Therefore, since the sample of the heater control identification plat enclosed with your letter identifies the extreme positions of the temperature control with the words 'hot' and 'cold,' it meets the requirements of section S5.2.2 concerning that requirement regardless of whether the color used for the hot extreme would be considered 'red' within the meaning of that section.; As to your question whether the color used for the hot extreme on th sample of the heater control identification plate is red, our visual inspection indicates that the color is orange rather than red. For guidance on the meaning of the color 'red,' we suggest that you refer to 49 CFR S172.407(d). That section, which is part of the Departments of Transportation's regulations concerning hazardous materials, establishes color tolerances for various colors, including red. The section indicates how to obtain copies of the Department's color tolerance charts or where they may be inspected. While the charts are not referenced by Standard No 101-80, they do provide guidance on the tolerances of various colors.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2620OpenMr. John J. Giesguth, Director, Bureau of Pupil Transportation, State of New Jersey, Department of Education, Division of Field Services, 225 West State Street, P.O. Box 2019, Trenton, NJ 08625; Mr. John J. Giesguth Director Bureau of Pupil Transportation State of New Jersey Department of Education Division of Field Services 225 West State Street P.O. Box 2019 Trenton NJ 08625; Dear Mr. Giesguth: This responds to your May 31, 1977, letter asking whether a bil presently before the New Jersey legislautre requiring 28-inch high seat backs and seat belts in all buses would be preempted by Federal regulations. Currently, Federal regulations require all school buses to be equipped with 20-inch high seat backs (measured from the seating reference point) and school buses with gross vehicle weight ratings of 10,000 pounds or less to be equipped with seat belts.; Federal preemption of State motor vehicle safety regulations i governed by Section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1381 *et seq.*) which states:; >>>Whenever a Federal motor vehicle safety standard established unde this title is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard. Nothing in this section shall be construed to prevent the Federal Government or the government of any State or political subdivision thereof from establishing a safety requirement applicable to motor vehicles or motor vehicle equipment procured for its own use if such requirement imposes a higher standard of performance than that required to comply with the otherwise applicable Federal standard.<<<; "The first sentence of Section 103(d) has the effect of preemptin safety standards of the States and their political subdivisions unless they are identical to applicable Federal safety standards that regulate the same aspect of vehicle or equipment performance. The second sentence of the section clarifies tvst the limitation on safety standards of general applicability does not prevent governmental entities from specifying additional safety features in vehicles purchased for their own use. The second sentence does not permit, however, these governmental entities to specify safety features that prevent the vehicle or equipment from complying with applicable Federal safety standards."; The law proposed in New Jersey would affect Federal requirement applicable to seat back height and seat belts. Since New Jersey requirements appear to impose a higher standard of safety than the Federal requirements in these areas, the State would be permitted to implement its standards for buses it purchases for its own use, but not for buses used by private schools. Further, it should be noted that all buses must continue to comply with the applicable Federal requirements.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3932OpenMr. Wataru Hyashibara, Manager, Certification Business Division, Mazda Motor Corporation, P. O. Box 18, Hiroshima, 730- 91, Japan; Mr. Wataru Hyashibara Manager Certification Business Division Mazda Motor Corporation P. O. Box 18 Hiroshima 730- 91 Japan; Dear Mr. Hayashibara: This responds to your letter concerning Federal Motor Vehicle Safet Standard No. 101, *Controls and Displays*. According to your letter, you are considering a bulb check system for telltales that operates while the ignition switch is turned to the 'on' position and the engine is not running. You stated that the proposed design of this system is such that all telltales subjected to the bulb check may emit light simultaneously when any malfunction occurs in the electrical charging system. You asked whether the proposed system would comply with applicable safety standards. The following represents our opinion based on the facts provided in your letter.; Section S5.3.1 of Standard No. 101 states: >>>A telltale shall not emit light except when identifying th malfunction or vehicle condition for whose indication it is designed or during a bulb check upon vehicles starting.<<<; There are thus only two situations in which it is permissible for telltale to emit light: (1) when the telltale is actually identifying the malfunction or vehicle condition for which it is designed, and (2) during a bulb check upon vehicle starting. The emitting of light by all telltales whenever a malfunction occurs in the electrical charging system does not fall within either of these catagories and is therefore not permitted by the standard.; This interpretation is limited to the specific factual situatio described above, i.e., where light would be emitted by all telltales whenever a malfunction occurs in the electrical charging system. In essence, your proposed design would replace the telltale for electrical charge, which is provided by most manufacturers to warn of such things as low voltage, with a warning message in the form of all telltales simultaneously emitting a light. This is not permitted by Standard No. 101, for the reasons stated above.; Your letter suggests an interpretation that the simultaneous lightin of all telltales subjected to the bulb check when any malfunction occurs in the electrical charging system could not be any violation of the requirements of S5.3.1, because it is the vehicle condition which 'is designed' by a manufacturer for all telltales to emit light. We do not agree with that suggested interpretation. Section S5.3.1's use of the words 'malfunction of vehicle condition for whose indication it is designed' refers back to the term '(a) telltale.' It is our opinion that the phrase is applicable only to the specific malfunction or vehicle condition for which a particular telltale is designed to warn the driver and not to a situation where all telltales are designed to collectively warn of a malfunction or vehicle condition.; Our interpretation is not dependent on whether a vehicle is equippe with a telltale for electrical charge or not.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2270OpenPFC David M. Phillips, 521st Signal Co., 11th Signal Group, Box 33, Ft. Huachuca, AZ, 85613; PFC David M. Phillips 521st Signal Co. 11th Signal Group Box 33 Ft. Huachuca AZ 85613; Dear PFC Phillips: This is in reply to your letter of April 8, 1976, asking about Stat laws applicable to fog lamps, driving lamps, and quartz-iodine halogen driving lamps.; The American Association of Motor Vehicle Administrators, 1828 Street, N.W., Washington, D.C. may be able to provide you answers with respect to State laws, as each State, rather than the Federal government, sets its own requirements for registration and use of motor vehicles within its borders.; The only aspect that you mentioned which we cover in our Federa vehicle lighting standard is the minimum and maximum height of headlamps above the road surface. These measurements are 24 inches and 54 inches respectively, measured from the center of the headlamp on the vehicle at curb weight. If a State has a law on maximum and minimum headlamp height it is required to be identical to this one. States may permit or prohibit fog lamps, driving lamps, and quartz-iodine halogen driving lamps as they choose since there are no Federal requirements for them.; Yours truly, Stephen P. Wood, Assistant Chief Counsel |
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ID: aiam3898OpenMr. Hiroshi Shimizu, Assistant Manager, Overseas Operations Dept., Tokai Rika Co., Ltd., Oguchi-Cho, Aichi Pref., 480-01, Japan; Mr. Hiroshi Shimizu Assistant Manager Overseas Operations Dept. Tokai Rika Co. Ltd. Oguchi-Cho Aichi Pref. 480-01 Japan; Dear Mr. Shimizu: This responds to your letter of December 19, 1984, concerning th requirements of Federal Motor Vehicle Safety Standard No. 209, *Seat Belt Assemblies*. You noted that section S4.1(e) of the standard provides that 'A Type 1 or Type 2 seat belt assembly shall be provided with a buckle or *buckles* readily accessible to the occupant....' [Emphasis added.] You asked whether the standard would permit a seat belt assembly with two buckles as shown in the schematic attached to your letter. The answer is that while Standard No. 209 would permit such an assembly, whether such an assembly can be installed in a particular vehicle is determined by Standard No. 208, *Occupant Crash Protection*.; Standard No. 208 specifies performance requirements for the protectio of occupants in a crash. Section S4.1.2.3.1 provides that Type 2 lap and shoulder belt systems used in passenger cars must have a nondetachable shoulder belt. Likewise, S4.2.2 provides that certain trucks and buses with Type 2 belts must have a nondetachable shoulder belt. The belt system you illustrated in your diagram consists of one continuous loop of webbing which serves as both the lap and shoulder belt. However, your design provides a separate buckle for the shoulder anchorage and thus an occupant could release the shoulder buckle and use the belt solely as a lap belt. Thus, we would not consider your design to have a nondetachable shoulder belt.; In addition, section S7.2 of the standard sets requirements for th latch mechanism of non-automatic seat belt assemblies used in passenger cars and certain trucks and buses. Section S7.2(c) requires that the latch mechanism used in those vehicles must release at a single point. Therefore, a two buckle system could not be used in those vehicles.; I hope this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0867OpenMr. Fred W. Cords,O.E.M. Marketing Manager,Minnesota Automotive, Inc.,Box 48/502 Patterson,Mankato,Minnesota 56001; Mr. Fred W. Cords O.E.M. Marketing Manager Minnesota Automotive Inc. Box 48/502 Patterson Mankato Minnesota 56001; Dear Mr. Cords:#This is in reply to your letter of September 19, 1972 asking whether the new hydraulic brake safety standard precludes the provision of a device using the service brake pressure to supplement normal parking brake performance.#Standard No. 105a does not prohibit the inclusion of such a device as original equipment in a motor vehicle, provided that the vehicle can meat the parking brake system requirements of the standard using the mechanical system alone.#Yours truly,Richard B. Dyson,Assistant Chief Counsel; |
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ID: aiam1775OpenMr. H. W. Gerth, Assistant Vice President, Mercedes-Benz of North America, Inc., One Mercedes Drive, Montvale, NJ 07645; Mr. H. W. Gerth Assistant Vice President Mercedes-Benz of North America Inc. One Mercedes Drive Montvale NJ 07645; Dear Mr. Gerth: This is in reference to your defect notification campaign (NHTSA No 75-0005) involving the front wheel bearings on certain Mercedes-Benz trucks, model L1113.; Since the notification was issued after the effective date of Publi Law 93-492, the provisions of this law apply to this notification. A copy of this law is enclosed for your information.; Specifically, the defect notification does not comply with sectio 153(a)(5) in that no specific date is given. Because remedy without charge is contingent upon actual dates, we believe the inclusion of a specific date is required. You must also include information that is responsive to section 153(a)(6). As the procedures referred to in that section have not been published, it is sufficient if you advise owners that they may write the Administrator, National Highway Traffic Safety Administration, Washington, D. C. 20590, if they find Mercedes- Benz to have failed or to have been unable to perform the repair satisfactorily.; In addition, we note from your defect report that you are notifyin first purchasers. Public law 93-492 has modified the statutory recipients of defect notification letters, and requires that notification be sent to the person who is registered under State law as the owner of the vehicle (section 153(c)(1)). First purchasers may also have to be notified under these requirements if registered owners cannot be found (153(c)(2)). We suggest you review these statutory changes and renotify owners, providing them with all required information. A letter containing the information in the notification letter forwarded to us plus the additional information referred to above will be considered to meet these statutory criteria.; Sincerely, Andrew G. Detrick, Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam3748OpenFrank B. Hill, Esq., Patent and Trademark Counsel, Bandag, Inc., Bandag Center, Muscatine, IA 52761; Frank B. Hill Esq. Patent and Trademark Counsel Bandag Inc. Bandag Center Muscatine IA 52761; Dear Mr. Hill: This responds to your recent letter to Mr. Kratzke of my staff, askin about marking requirements applicable to truck tires retreaded for non-highway use. You stated in your letter that the retreaded tires would be mounted only on vehicles used in shipyard areas to move cargo around. I will answer the three questions you raised in the order you presented them.; >>>1. *Is it required that a retreader put its DOT identification mar on truck tires when they are retreaded for non-highway use?*<<<; It is not possible to give a simple yes or no answer to this question 49 CFR Part 574, *Tire Identification and Recordkeeping*, sets forth certain marking requirements which must be met by manufacturers and retreaders of tires, including the requirement in section 574.5 that a DOT identification mark be molded on all new and retreaded tires. However, section 574.1 specifies that the requirements of Part 574 apply only to new and retreaded *tires for use on motor vehicles*. Hence, the question which must be answered to determine if a retreader is required to put its DOT identification mark on a retreaded tire is whether the tire is for use on motor vehicles.; 'Motor vehicle' is defined at 15 U.S.C. 1391(3) as 'any vehicle drive 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.' If these retreaded tires are for use on forklifts or other types of mobile construction equipment intended and sold primarily for off-road use, the retreader would not be required to mold a DOT identification mark on the tires, because the tires would not be for use on motor vehicles. This is true even if these types of vehicles are incidentally used for highway travel from one job site to another.; If, on the other hand, the vehicles on which the retreaded tires ar mounted are conventional on-road trucks simply being used in a shipyard, the retreaders would be required to comply with the requirements of Part 574, because the tires are for use on motor vehicles. The determination of whether the retreaded tires are for use on motor vehicles must be made initially by the retreader, but it would be subject to review by this agency.; >>>2. *If a DOT identification mark is not required, is there any othe notice that is required on the retreaded trucks tires, retreaded for non-highway use?*<<<; If the retreaded truck tires are not subject to the Part 574 markin requirements, because they are not for use on motor vehicles, there are no other marking requirements applicable to retreaded truck tires.; >>>3. *If no notice is required and the DOT identification mark is no required, would it be permissible to place a disclaimer notice such as 'Not Retreaded for Highway Use' on the retreaded truck tire?*<<<; This sort of notice would be permitted, and would be a usefu disclosure for the retreader and the user of the tire, to show the intended use of the tire. Such a notice would not affect the retreader's duty to determine whether the tire was retreaded for use on motor vehicles, and mold its DOT identification mark on the sidewall of the tire if it were for use on motor vehicles.; Should you have any further questions or need more information on thi subject, please contact Mr. Steve Kratzke at this address or at (202) 426- 2992.; 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.