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: aiam1392OpenMr. George C. Nield, Engineering Advisor, Busby(sic) Rivkin(sic) Sherman(sic) Levy and Rehm, 816 Connecticut Avenue, N.W., Washington, DC 20006; Mr. George C. Nield Engineering Advisor Busby(sic) Rivkin(sic) Sherman(sic) Levy and Rehm 816 Connecticut Avenue N.W. Washington DC 20006; Dear Mr. Nield: This is in reply to your letter of December 13, 1973, asking whethe glazing in the rear quarter windows of the Datsun model HLB-210 may, consistently with Motor Vehicle Safety Standard No. 205, be manufactured of AS 3 glazing material. This depends, as you point out, on whether this glazing is used 'at levels requisite for driving visibility' under American National Standards Institute Standard ANS Z26.1-1966, incorporated into Standard No. 205. You refer in your letter to section 1017(a) of the California Vehicle Code which states:; >>>Side windows to the rear of the driver and the rear windows not use for vision directly to the rear are not considered areas requisite for driving visibility.<<<; The locations where the use of AS 3 glazing is permitted are set fort on page 12 of ANS Z26. AS 3 glazing may be used, 'anywhere in a motor vehicle except in passenger car windshields and in the following locations at levels requisite for driving visibility....(2) *Passenger automobiles and taxicabs*. Glazing of *all* windows including rear window, *all* interior partitions, and *all* apertures created for window purpose. (emphasis added); The only exclusion from the broad prohibition against the use of AS glazing in passenger cars is 'at levels not requisite for driving visibility.' We do not agree with the California Code provision. We consider the word 'levels' in Standard 205 to mean vertical heights in relation to the driver's eyes. We, therefore, cannot concur in the application of the 'levels requisite for driving visibility' concept as it appears in Standard No. 205 to complete windows or other glazing areas of passenger cars.; With respect to the Datsun model in question, there is no evidence i your letter that the windows in question are not at a level requisite for driving visibility. In fact, they appear to include levels of a driver's normal eye point.; The NHTSA presently hopes to publish a revised notice of propose rulemaking regarding direct fields of view in the fall of 1974. Previous proposals regarding this subject were withdrawn by notice published March 7, 1973 (38 FR 6194).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3655OpenThe Honorable Eldon Rudd, House of Representatives, Washington, DC 20515; The Honorable Eldon Rudd House of Representatives Washington DC 20515; Dear Mr. Rudd: This responds to your recent letter on behalf of your constituent, Mrs Jan Wilson, asking whether Federal law restricts motorists from having darkly tinted films installed on the windows of their automobiles.; The National Highway Traffic Safety Administration has authority t govern the manufacture of new motor vehicles and motor vehicle equipment. We have promulgated Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials*, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance. Seventy percent transmittance is required in all areas requisite for driving visibility, which includes the windshield and all windows in passenger cars. This specification for light transmittance precludes darkly-tinted windows in new automobiles.; The agency has stated in past interpretations that solar films are no glazing materials themselves, and would not have to comply with Standard No. 205. However, use of such films on motor vehicles in certain cases would be prohibited if the vehicle glazing no longer complied with the light transmittance requirements of the standard (most of these films do reduce light transmittance below 70%). If a vehicle manufacturer or dealer places the film on glazing in a vehicle prior to sale of the vehicle, that manufacturer or dealer has to certify that the glazing continues to be in compliance with the requirements of Standard No. 205 (i.e., has to certify that the glazing still has a transmittance of at least 70%).; Regarding vehicles that have already been purchased, sectio 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381) provides that no manufacturer, distributor, dealer or motor vehicle repair business shall knowingly render inoperative any device or element of design installed on or in a motor vehicle in compliance with an applicable motor vehicle safety standard. Thus, none of those persons may knowingly install a solar film on a vehicle for its owner if the vehicle glazing would no longer meet the light transmittance requirements of Standard No. 205. Whether this would be the case would have to be determined by the person making the installation. Violation of this provision could subject the manufacturer, distributor, dealer, or motor vehicle repair business to civil penalties up to $1,000 for each violation.; Please note, however, that under Federal law the vehicle owner ma alter his or her vehicle as is desired. This agency does not govern use of vehicles by owners, this is left to the States. Thus, under Federal law, an owner could install solar film on his or her vehicle whether or not such installation affected compliance with Standard No. 205.; In summary, Federal law does not preclude Mrs. Wilson from havin darkly tinted film on her passenger car, provided she installed the film herself. However, if a manufacturer, dealer, distributor or motor vehicle repair business (including an auto tint shop) installed the film for Mrs. Wilson, they are in violation of Federal law if the glazing no longer meets the 70% light transmittance requirements of Standard No. 205. The State of California is, of course, free to prohibit vehicle owners from operating vehicles with darkly tinted glazing in its jurisdiction.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1668OpenMr. Max L. Hill, Camping Trailer Division, Coleman Company, Incorporated, P. O. Box 111, Somerset, PA 15501; Mr. Max L. Hill Camping Trailer Division Coleman Company Incorporated P. O. Box 111 Somerset PA 15501; Dear Mr. Hill: This is in acknowledgment of your Defect Information Report, i accordance with the defect reporting regulations, Part 573.; The Defect Information Report involves: 1,100 - 1975 Valley Forg camping trailers with McCreary tires size 5.70-8 which may experience tread delamination.; The following National Highway Traffic Safety Administratio identification number has been assigned to the campaign *74- 0206*. The first quarterly status report for this campaign is required to be submitted by February 5, 1975. Please refer to the above number in all future correspondence concerning this campaign.; 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. A copy of this regulation is enclosed. Specifically, the second sentence of your letter describes the defect as existing in the tires, where it should have described the defect as existing in the vehicle itself. The reference to 'item of motor vehicle equipment' in Part 577 applies only to equipment campaigns where vehicles are not involved.; Since this discrepancy in your notification letter does not appear t discourage owner response, mailing of a revised letter will not be required. It is hoped that these comments will assist you in the event that another defect notification campaign becomes necessary at some time in the future.; Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam4190OpenMr. Ron Marion, Specification Engineer, Thomas Built Buses, L.P., P.O. Box 2450, High Point, NC 27261; Mr. Ron Marion Specification Engineer Thomas Built Buses L.P. P.O. Box 2450 High Point NC 27261; Dear Mr. Marion: This responds to your May 21, 1986 letter requesting an interpretatio of Federal Motor Vehicle Safety Standard No. 222, *School Bus Passenger Seating and Crash Protection*, as it applies to safety belts on large school buses. You asked first whether it is acceptable to install two safety belts on a 39-inch bench seat. Your second question asked whether such a seat would be designated as a two- or three- passenger seat.; In response to your first question, Standard No. 222 currently does no prohibit you from providing two safety belts on a 39-inch bench seat. This is because NHTSA does not require or set specifications for safety belts installed for passengers on large school buses, but for the requirement that the installation method not interfere with vehicles' compliance with applicable motor vehicle safety standards. However, the agency is currently considering an amendment to Standard No. 222 which would affect the voluntary installation of safety belts on 39-inch bench seats. If we adopt changes to the standard proposed in a notice published on October 10, 1985, safety belts voluntarily installed on large school buses must meet requirements similar to those established for safety belts on small school buses. Under the proposed requirements, manufacturers voluntarily installing safety belts would have to install three safety belts on a 39-inch seat. We are currently evaluating comments received on the proposal, and final action is anticipated in the near future.; In response to your second question, since your current option t install voluntarily two safety belts on a 39-inch bench seat does not affect your responsibility under the National Traffic and Motor Vehicle Safety Act to manufacture school buses which comply with all applicable requirements of Standard No. 222, the 39-inch bench seat to which you refer must be designated as a 3-passenger seat under S4.1 of the standard. You as a manufacturer must ensure that the seat meets the forward and rearward performance requirements, and other applicable requirements of Standard No. 222, based on calculations of *three* seating positions and the requisite force applications. While your bench seat might be occupied by fewer persons due to the safety belts, that calculation helps to assure that the seat provides adequate protection when occupied by the maximum number.; We note further that since under S4.1 a 39-inch bench seat i considered to have three designated seating positions, manufactures must not provide more than three safety belts on a 39-inch bench seat or otherwise imply that the seat is capable of carrying more than three passengers.; If you have any further questions, please let us know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam2947OpenMr. Melvin Ives, President, United Bus Sales, Inc., 6700 S. Garfield Avenue, Bell Gardens, CA 90201; Mr. Melvin Ives President United Bus Sales Inc. 6700 S. Garfield Avenue Bell Gardens CA 90201; Dear Mr. Ives: This responds to your November 6, 1978, letter asking for a interpretation of the warning buzzer requirement of Standard No. 217, *Bus Window Retention and Release*.; The standard requires a warning buzzer to sound when an emergency doo release mechanism is not in the closed position and the vehicle's ignition is on. From conversations with you and our Office of Vehicle Safety Compliance, we have determined that your rear emergency door uses a warning buzzer that sounds when the door release mechanism is not in the closed position unless someone continues to exert pressure to hold the door closed. The National Highway Traffic Safety Administration considers such a warning device to be in compliance with the standard. The purpose of the warning alarm is to warn passengers and the driver when a door is accidentally left in the open condition while the vehicle ignition is in the on position. You device appears to meet the intent of the standard.; We have discussed this issue with Mr. Jerry Alexander of the Californi Highway Patrol, and he has indicated that he will accept our determination. We are sending him a copy of this letter for his information.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3205OpenMr. F. Michael Petler, Suzuki Motor Co., Ltd., 13767 Freeway Drive, Santa Fe Springs, California 90670; Mr. F. Michael Petler Suzuki Motor Co. Ltd. 13767 Freeway Drive Santa Fe Springs California 90670; Dear Mr. Petler: This is in response to your letter of February 7, 1980, asking whethe a partial vehicle identification number (VIN) may be stamped into the frame of the Suzuki motorcycles under the certification label.; The answer is yes. The use of identifying numbers other than the VIN i allowed if the numbers cannot be confused with the VIN. In the situation you described, the identification number would be hidden from view by the certification label. Since the label is required to be riveted or permanently affixed to the vehicle (Part 567 of Title 49, Code of Federal Regulation), the hidden identifying number is not likely to become visible during the life of the vehicle. Therefore, there appears to be no chance that the number would be confused with the VIN.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1238OpenMr. Richard Hrejsa, 4531 Grove Avenue, Brewyn, IL 60402; Mr. Richard Hrejsa 4531 Grove Avenue Brewyn IL 60402; Dear Mr. Hrejsa: This is in response to your letter of June 4, 1973, requestin information on remedies for a transferor's failure to make an accurate odometer disclosure statement. I apologize for our delay in replying.; Title IV of the Motor Vehicle Information and Cost Savings Act, Publi Law 92-513, (1) prohibits the resetting or altering of an odometer to change the miles indicated on it, and (2) establishes a requirement that a transferor (seller) make a written odometer disclosure to his transferee (buyer) at the time of sale. These provisions of the law were in effect when you purchased your car in May 1973.; The two remedies for violations of the law are (1) a private civi action for $1,500 or treble damages by a subsequent purchaser of the car, and (2) a suit by the Untied States Attorney to restrain further violations of the Act. This second remedy is normally utilized only in the case of repeated violations.; If the dealer who sold you the car altered or reset the mileage afte January 18, 1973, you may have a civil action against him. Also, if it is as it appears in your letter, the dealer made a false and incomplete mileage disclosure to you after March 1, 1973, which may also make him civilly liable to you. His purchase of the car in October 1972 has no bearing on his disclosure obligations to you.; You may wish to consult with an attorney about your rights in thi matter. Enclosed are a copy of the Act and implementing regulations for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0583OpenMr. Robert M. Martin, Director of Central Services, City of Lynchburg, Box 60, Lynchburg, VA 24505; Mr. Robert M. Martin Director of Central Services City of Lynchburg Box 60 Lynchburg VA 24505; Dear Mr. Martin: This is in reply to your letters of December 20, 1971, and January 4 1972, concerning dump trucks recently purchased by the city of Lynchburg. You state that the trucks have a 24,000 GVW rating (rear axle 17,500 pounds, front axle 7,000 pounds), and were delivered with 8.25-20 tires, and ask whether there is a Federal requirement that restricts GVW rating according to tire size.; Beginning January 1, 1972, Federal regulations (49 CFR Parts 567, 568 have required all motor vehicle manufacturers to affix a label to their vehicles that contains both a gross vehicle weight rating (GVWR) and a gross axle weight rating for each axle (GAWR). These ratings are to be established by the manufacturer based upon all vehicle systems including tires. The requirements apply to the manufacturer, however, and not to the purchaser, if the vehicle is completed when he receives it. Nor is the regulation designed to regulate vehicles-in-use, which are subject to State regulation, but it is possible that some States may use these figures as a basis of determining whether vehicles are overloaded.; With reference to your particular trucks, it appears that they wer manufactured before January 1, 1972, and the regulations are therefore not applicable to them. However, according to the 1971 Tire and Rim Association Yearbook, which sets recommended load and inflation pressures for all vehicle tires, the 8.25-20 10-ply tire has a recommended maximum load, for dual usage, of 3,550 pounds at 75 psi. Assuming 4 tires on the rear axle, this would be equal to a load rating of 14,200 pounds, lower than the 17,500 pounds at which the axle is rated. For single usage, the tire is rated at 4,050 pounds at 85 psi. Assuming 2 tires on the front axle, the maximum load for the axle would be 8,100 pounds, which, unlike the rear axle, is greater than the load rated for the axles.; A copy of our Certification regulations, which contain the requirement for GVWR and GAWR is enclosed for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0079OpenMr. L. P. Knipe, Vice President - Sales, Ultra, Inc., 101 West Fifth, Hutchinson, KS 67501; Mr. L. P. Knipe Vice President - Sales Ultra Inc. 101 West Fifth Hutchinson KS 67501; Dear Mr. Knipe: Thank you for your letter of February 27, 1968, concernin certification of the Ultra Van Motorhome as a multipurpose vehicle. An examination of the information submitted indicates that the Ultra Van Motorhome would properly be classified as a multipurpose passenger vehicle within the definition contained in Section 255.3(b) 23 CFR, Initial Federal Motor Vehicle Safety Standards.; Section 114 of the National Traffic and Motor Vehicle Safety Act o 1966 requires every manufacturer of a motor vehicle or motor vehicle equipment to furnish certification of compliance with applicable standards. Details of certification were published as a Federal Register, Vol. 32, No. 215 on November 4, 1967. Your attention is invited to the enclosed copies of these documents and the Federal Motor Vehicle Safety Standards.; We trust we have been of assistance to you. Sincerely, Joseph R. O'Gorman, Acting Director, Office of Performanc Analysis, Motor Vehicle Safety Performance Service; |
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ID: aiam2044OpenMr. Kenneth J. Mason, 1314 Spruce Street, Wausau, WI 54401; Mr. Kenneth J. Mason 1314 Spruce Street Wausau WI 54401; Dear Mr. Mason: We have received your letter of August 7, 1975, concerning the Unifor Tire Quality Grading Standards established by this agency. Although the formal comment period for the proposals on which this regulation is based ended April 23, 1975, we appreciate your support for the regulation as issued. A copy of your letter has been placed in our public files.; Thank you for expressing your interest. Sincerely, Frank A. Berndt, Acting 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.