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: aiam1438OpenMr. Philip H. Taft, Tire Retreading Institute, 1343 L Street, N.W., Washington, D.C. 20005; Mr. Philip H. Taft Tire Retreading Institute 1343 L Street N.W. Washington D.C. 20005; Dear Mr. Taft: This is in reply to your letter of February 22, 1974, concerning a article in the November 1973 *Retreader's Journal* entitled 'Repairing Torn Beads.' You ask whether the article is correct when it states that casings with cord exposed in the bead area may be retreaded.; Standard No. 117 (S5.2) prohibits the retreading of any casing on whic bead wire or cord fabric is exposed before processing. 'Processing' encompasses the entire process, including the making of any needed repairs, by which a casing is retreaded. The NHTSA has taken the position that the only exception to this prohibition is that casings with exposed chafer fabric bay be retreaded. A casing that before processing has any exposed bead or cord material other than chafer fabric, however, may not be retreaded. Therefore, insofar as the Retreader's Journal article states that casings with exposed cord in the bead area may not be retreaded it is incorrect. We have sent a copy of this letter to the *Retreader's Journal*.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3405OpenMr. James J. Schultz, Severy, Incorporated, 2233 El Segundo Boulevard, El Segundo, CA 90245; Mr. James J. Schultz Severy Incorporated 2233 El Segundo Boulevard El Segundo CA 90245; Dear Mr. Schultz: This responds to your recent letter asking whether a 4-wheel driv pickup truck must comply with Safety Standard No. 216, *Roof Crush Resistance*. You also ask whether the definitions of vehicle classification under Federal regulations are mutually exclusive.; The application section of Safety Standard No. 216, section 3 specifies that the standard applies to passenger cars. This means that the standard applies *only* to passenger cars. Therefore, the standard does not apply to a pickup truck.; The definitions of the basic vehicle classifications found in 49 CF Part 571.3 are mutually exclusive. If a vehicle falls within the definition of a 'truck,' the vehicle is not also within the definition of a 'passenger car.' The definition of a passenger car does not specifically exclude trucks because the definition is based on the function of the vehicle. Thus, a passenger car is defined as a motor vehicle designed for carrying persons. A truck, on the other hand, is defined as a vehicle designed primarily for the transportation of property or special purpose equipment. Since a pickup is designed primarily for carrying property and not persons, it is a truck and not a passenger car. Each motor vehicle has a certification label attached to its door which specifies the vehicle's classification.; I hope this has clarified any questions you had concerning vehicl classification under the Federal Motor Vehicle Safety Standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0383OpenMr. Charles J. Calvin, Managing Director, Truck Trailer Manufacturers Association, 1413 K Street, NW., Washington, DC, 20005; Mr. Charles J. Calvin Managing Director Truck Trailer Manufacturers Association 1413 K Street NW. Washington DC 20005; Dear Mr. Calvin: This replies to your letter of June 30, 1971, and has reference t previous discussions your Mr. Gray and Mr. Wilson had with members of my engineering staff concerning lamp and reflector locations for trailers.; We have reviewed the drawings submitted and find that the locations an types of lamps and reflectors to be acceptable under the provisions of the Motor Carrier Safety Regulations. As we noted in past correspondence on this subject, a license plate light is not required by our present regulations. Again, the impression should not be given that this lamp, if not required by State regulation, must be installed on vehicles not certified to comply with Motor Vehicle Safety Standard No. 108.; The Bureau of Motor Carrier Safety appreciates the efforts of you association in aiding motor carriers to understand and comply with the Motor Carrier Safety Regulations.; Sincerely yours,Robert A. Kaye, Director |
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ID: aiam2644OpenMr. Phillip A. O'Reilly, Houdaille Industries, Inc., One M & T Plaza, Buffalo, NY 14203; Mr. Phillip A. O'Reilly Houdaille Industries Inc. One M & T Plaza Buffalo NY 14203; Dear Mr. O'Reilly: This is in response to your letter of June 14, 1977, commenting o certain statements made in the May 12, 1977, Federal Register notice (42 FR 24056) responding to petitions for reconsideration of Part 581, *Bumper Standard*. Specifically, you object to the reference in the notice to the Houdaille cost-benefit study and to the statement that the Harris poll indicated that a 'significant' number of people consider 1/2 inch dents to be damage they would repair.; The notice referred to the Houdaille study as one which indicated tha the damage criteria contained in Part 581 could be met in a cost-beneficial manner. The agency did not represent that the Houdaille study demonstrated that Part 581 standard was the most cost-effective standard that could be promulgated.; With regard to your objection to our characterization of the number o people who would repair a 1/2 inch dent as 'significant,' you should note that it is the conclusion of the agency that the percentage of those people polled (25 percent) who expressed concern over a 1/2 inch dent is *significant*.; Regarding your suggestion that a 2 1/2 mph impact test be adopted, th agency proposed such a change in Part 581 on January 2, 1975 (40 FR 10) and determined after a period for submission of comments and a 2-day public hearing that such a reduction should not be adopted (40 FR 11598, March 12, 1975). The agency's position on that matter has not changed.; We appreciate your comments and have placed your letter in the publi docket.; Sincerely, Joan Claybrook |
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ID: aiam0679OpenMr. C. W. Rose, Chairman of the Board, Rose Manufacturing Co., 2700 West Barberry Place, Denver, CO 80204; Mr. C. W. Rose Chairman of the Board Rose Manufacturing Co. 2700 West Barberry Place Denver CO 80204; Dear Mr. Rose: This is in reply to your letters of March 23, 1972, and March 27, 1972 concerning our previous letter to you dated March 10, 1972.; We recognize your contribution to safety and your deep persona involvement in child harnesses. Harnesses, such as yours, offer many desirable features. The child is free to move about, and he is adequately restrained if the harness system is properly adjusted and anchored. Effective harness systems can probably be produced at modest cost.; There certainly can be no objection to the upper torso restrain provided by a good harness system. Indeed, this is a very important feature which is required because of the child's special skeletal structure.; On the other hand, restraints which are anchored to inadequat structures or which allow excessive motion of the child in a crash cannot be condoned. Actual thirty mile-per-hour, sixteen g dynamic sled tests of child harnesses anchored as you recommend have shown that a severe problem exists with the anchorage system. Quoting the University of Michigan Highway Safety Research Institute Report, *Child Seat and Restraint Systems Test Program*, DOT/HS-800-376, in the test at 30 mph the adult seat back broke away due to the load imposed by the restraint system tether. This allowed the dummy to move forward far enough to cause potential contact with the vehicle interior.' This test was conducted using a heavy duty Bostrom truck bucket seat and utilized only the thirty-pound, three-year-old child dummy, restrained by a Sears small harness. The present typical seat back strengths are, thus, inadequate to support a harness system which depends upon the seat back. It is our intention to encourage improvements in seat back strength for automobile production by future rule making action.; Since your harness is recommended for children up to fifty pounds an since most passenger car seats are not as strong as the test seat, we expect the situation to be even more serious in realistic usage conditions which also normally encounter appreciably higher load levels in thirty mile-per-hour crashes. This is why we object to your system of anchorage. Thus, our position is as stated in our previous letter to you.; We hope that you will consider other methods of anchoring your chil harness which will prevent seat back failure and resulting excessive occupant excursions.; We appreciate your sincere interest and concern in this matter. W emphatically do believe that child harnesses play a vital role in child restraints.; Sincerely, Charles H. Hartman, Deputy Administrator |
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ID: aiam2022OpenMr. Dennis Replansky, Four Penn Center Plaza, Philadelphia, PA 19103; Mr. Dennis Replansky Four Penn Center Plaza Philadelphia PA 19103; Dear Mr. Replansky: This responds to your recent request for a discussion of wha constitutes the manufacture of a new trailer when used components from an existing trailer are utilized. As you are aware, a newly-manufactured air-braked trailer must, in all but a few cases, be equipped with an air brake system that conforms to Standard No. 121, *Air Brake Systems*.; The use of new components in combination with used components t assemble a complete vehicle is a common practice in both truck and trailer operations. The National Highway Traffic Safety Administration (NHTSA) has recognized this commercial practice by establishing that the use of a new body on a used 'chassis' that has already been certified does not constitute the manufacture of a new vehicle. In contrast, placing a used body on a new chassis that has never been certified as a vehicle has been determined to create a newly-manufactured vehicle that must be certified. This distinction did not present difficulty to trailer manufacturers in the past, when they were only required to meet the lighting requirements of Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*.; Since implementation of Standard No. 121, however, manufacturers hav had to determine whether the particular assembly they undertake contains a used 'chassis' which would not be required to meet the air brake standard. As a general matter, the NHTSA has stated that, as a minimum, the running gear (the axles, wheels, suspension, and related components sometimes known as a bogie) and main frame of the existing vehicle must be used to qualify as a used 'chassis'. However, the many different types of trailer construction make it difficult to determine what constitutes the main frame of some configurations. The NHTSA has concluded that the load-bearing structural member(s) which run the length of the vehicle and support the trailer will be considered to be the 'main frame'.; In the case of monocoque van construction, the trailer side walls whic constitute the main load-bearing members through the length of the vehicle must be reused as the main frame in addition to the running gear, or else the rebuilding operation will constitute manufacture of a new vehicle.; In the case of container chassis, the box frame that consitutes (sic the main load- bearing member through the length of the vehicle must be reused as the main frame in addition to the running gear, or else the rebuilding operation will constitute manufacture of a new vehicle.; In the case of a platform trailer, the main frame members which run th length of the trailer must be reused in addition to the running gear, or else the rebuilding operation will constitute manufacture of a new vehicle.; In the case of a tank trailer in which the tank serves the purpose o and replaces frame rails, the tank must be reused as the main frame in addition to the running gear, or else the rebuilding operation will constitute manufacture of a new vehicle. If a separate frame serves as the load-bearing member through the length of the vehicle, the tank could be replaced without the operation constituting the manufacture of a new vehicle. An inner tank may be replaced without certification as a new vehicle if the inner tank does not serve as a main load-bearing member.; Modifications of existing trailers to increase or decrease volumetri capacity or vehicle length are generally permitted without recertification. For example, the barrel of a tank trailer may be lengthened in response to the new weight limits without recertification of the vehicle.; In closing, it should be noted that Bureau of Motor Carrier regulation may differ on modification or rebuilding of vehicles in interstate commerce.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2472OpenMr. Michael E. Bufkin, 1136 Gail Lane, Sleepy Hollow, IL 60118; Mr. Michael E. Bufkin 1136 Gail Lane Sleepy Hollow IL 60118; Dear Mr. Bufkin: This responds to your November 12, 1976, question whether a tire bran name owner is required by S 574.7(b) of Part 574, *Tire Identification and Recordkeeping*, to establish and maintain specified purchaser information on its tires if the distributor or dealer fails to provide that information as specified by S 574.8 of the regulation. You also ask whether a tire registration form with dimensions other than those specified in Figure 3 of the regulation may be provided to tire distributors and dealers.; Section 158(b) of the National Traffic and Motor Vehicle Safety Act (1 U.S.C. S 1418(b)) mandates the tire manufacurer's (sic) (including brand name owner's) responsibility to establish and maintain the purchaser information, independent of the distributor's or dealer's cooperation:; >>>S 158(a)(1) * * * * * (b) Every manufacturer of motor vehicle or tires shall cause th establishment and maintenance of records of the name and address of the first purchaser of each motor vehicle and tire produced by such manufacturer * * *<<<; Thus, the brand name owner's responsibility is a statutory one independent of any interpretation of Part 574.; With regard to the size of the tire registration form, S 574.7(a permits the use of any size form unless a dealer requests forms that conform to the universal format set forth in Figure 3. The agency has interpreted the requirement for provision of the universal format to not apply in the case of a dealer that sells only one brand of tire.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2188OpenMr. Stuart R. Perkins, Director, Vehicle Safety, Jeep Corporation, 14250 Plymouth Road, Detroit, MI 48232; Mr. Stuart R. Perkins Director Vehicle Safety Jeep Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Perkins: This responds to Jeep Corporation's October 16, 1975, petition t initiate rulemaking to amend the present definition of 'Unloaded vehicle weight' (49 CFR S571.3) which reads:; >>>'Unloaded vehicle weight' means the weight of a vehicle with maximu capacity of all fluids necessary for operation of the vehicle, but without cargo or occupants.<<<; Jeep requests that the definition be amended to 'indicate that th unloaded vehicle [weight] does not include work-performing accessories which may be available as original equipment accessories.' The Jeep petition argues that the impracticality of conducting some dynamic testing with 'work-performing accessories' in place may force the discontinuance of some factory-installed accessories although factory installation may be more safe than a subsequent aftermarket installation.; The Jeep Corporation petition is denied. As a general matter, the NHTS has established that a vehicle which is designed to accept an optional component must be capable of meeting all applicable standards with the component installed. The NHTSA has evaluated the potential problems of dynamic testing with heavy or protruding accessories in place and concludes that a decision on the practicality and wisdom of so doing should be made on a 'standard-by-standard' basis. As you noted, the NHTSA has provided for removal of work-performing accessories in conducting compliance tests under Standard No. 219, *Windshield Zone Intrusion*. If Jeep considers dynamic testing in other standards to be unjustifiably burdensome because of the necessity of testing with all accessories in place, it would be appropriate to petition for rulemaking to amend the standard in question.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2921OpenMr. Dominic S. Piacenza, Franklin Pierce Law Center, 2 White Street, Concord, NH 03301; Mr. Dominic S. Piacenza Franklin Pierce Law Center 2 White Street Concord NH 03301; Dear Mr. Piacenza: This is in response to your letter of November 9, 1978, asking whethe a memorandum of understanding exists between the National Highway Traffic Safety Administration (NHTSA) and the Federal Trade Commission (FTC) concerning the apparent overlapping jurisdiction regarding tire marketing practices created by Section 203 of the National Traffic and Motor Vehicle Safety Act of 1966 (Safety Act)(15 U.S.C. 1423). You ask whether NHTSA's jurisdiction extends solely to safety- related issues.; NHTSA's authority is not confined solely to the area of motor vehicl and traffic safety. For example, under the Motor Vehicle Information and Cost Savings Act (15 U.S.C. 1901) the agency has been given authority over the areas of fuel economy and economic losses to consumers as they relate to automobiles. While the Safety Act is primarily concerned with safety issues, Section 203 of that law does provide NHTSA with limited authority over tire marketing practices. The Uniform Tire Quality Grading Standards (49 CFR 575.104), issued by NHTSA under the authority of Section 203, provide information to consumers in tire performance areas relating to both safety and economic issues.; While the FTC is aware of and supports NHTSA's efforts in the field o tire grading, no memorandum of understanding exists with regard to the scope of NHTSA's activities. Section 205 of the Safety Act (15 U.S.C. 1425) does state that, in the event of conflict between orders or regulations issued under the Safety Act concerning motor vehicle tires and FTC orders or interpretations, the orders or regulations issued under the Safety Act shall prevail.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3633OpenMr. Matt Guzzetta, Vice President, Don Vesco Products, Inc., 7565 North Avenue, Lemon Grove, CA 92045; Mr. Matt Guzzetta Vice President Don Vesco Products Inc. 7565 North Avenue Lemon Grove CA 92045; Dear Mr. Guzzetta: This is in reply to your letter of September 15, 1982, asking about th legality of 'covering of a headlamp on a motorcycle with a clear cover.'; You reported that manufacturers of motorcycles and fairings ar producing such covers. The National Highway Traffic Safety Administration views this practice as prohibited and will take appropriate steps to make its views known. The legal authority for this is based upon a requirement of the SAE incorporated by reference in Motor Vehicle Safety Standard No. 108 or, alternatively, paragraph S4.1.3 of that standard.; SAE Standard J580 (both a and b versions), *Sealed Beam Headlam Assembly*, is incorporated by reference in Tables I and III of Standard No. 108 as one of the standards pertaining to headlamps for use on passenger cars, trucks, buses, and multipurpose passenger vehicles. A paragraph in each version states that, 'When in use, a headlamp shall not have any styling ornament or other feature, such as a glass cover or grill, in front of the lens.' SAE J580a applies to all sealed beam headlamps, while the scope of J580b is considerably narrower, including only those not covered by SAE J579c.; The principal referenced SAE material for motorcycle headlamps is J584 *Motorcycle Headlamps*. As options, both J584 and S4.1.1.34 of Standard No. 108 allow, in effect, a motorcycle to be equipped with one half of any sealed beam system permissible on four-wheeled motor vehicles.; Paragraph S4.1.3 of Standard No. 108 forbids the installation o additional equipment 'that impairs the effectiveness of lighting equipment required' by Standard No. 108. Because of moisture accumulation, discoloration, cracks, etc., a glass or plastic cover might tend over a period of time to diminish or distort the headlamp beam. This is of particular concern with reference to the unsealed headlamps implicitly permitted by SAE J584 because of the tendency of the reflector to deteriorate with age.; For the reasons stated above, the agency has concluded that no headlam may have a glass or plastic shield in front of it when in use, regardless of the type of vehicle on which it is used.; As for the turn signals, no part of the vehicle may impair thei visibility through horizontal angles 45 degrees to the right and left of the vehicle (for right and left turn signals respectively) measured at the longitudinal axis of the vehicle. An unobstructed illuminated area of outer lens surface of at least 2 square inches excluding reflex is necessary to meet this requirement. You will have to judge for yourself whether the turn signal requirements are met with your planned cover in place.; If you have any further questions, we shall be happy to answer them. 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.