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: 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: aiam1770OpenMr. Alberto Negro, Director Fiat,Research & Development,Parklane Towers West,One Parklane Boulevard,Dearborn, Michigan 48126; Mr. Alberto Negro Director Fiat Research & Development Parklane Towers West One Parklane Boulevard Dearborn Michigan 48126; Dear Mr. Negro:#This responds to your December 30, 1974, questio whether the requirements if S5.3.2 of Standard No. 105/75, *Hydraulic brake systems*, would be satisfied by the use of a 4- to 8-second activation of the brake indicator lamp, activated when the ignition switch is placed in the 'on' position. S5.3.23 requires:#>>>S5.3.2 All indicator lamps shall be activated as a check of lamp function either when the ignition (start) switch is turned to the 'on' (run) position when the engine is not running, or when the ignition (start) switch is in a position between 'on' (run) and 'start' that is designated by the manufacturer as a check position.<<<#A 4- to 8-second activation when the ignition switch is placed in the 'on' position as a check of brake indicator lamp function would satisfy the requirements if S5.3.2.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam4088OpenGrace Cheng, Yue Loong Motor Engineering Center, P.O. Box 510, Taoyuan, Taiwan 330, REPUBLIC OF CHINA; Grace Cheng Yue Loong Motor Engineering Center P.O. Box 510 Taoyuan Taiwan 330 REPUBLIC OF CHINA; Dear Ms. Cheng: Thank you for your letter of February 5, 1986, concerning th requirements of Standard No. 208, *Occupant Crash Protection*. You asked whether S4.1.2.3.1(a) of the standard requires a vehicles with a manual, nondetachable Type 2 seat belt assembly that conforms to Standard No. 209, *Seat Belt Assemblies*, to meet the frontal crash protection requirements of S5.1 in a perpendicular impact.; The answer is that such a Type 2 safety belt system currently does no have to meet the frontal crash protection requirements of the standard. However, we have recently set 30 mph frontal crash protection requirements for manual Type 2 safety belts used in the frontal outboard seating positions in future passenger cars. The dynamic test requirement for manual safety belts would go into effect on September 1, 1989, if the automatic restraint requirement of Standard No. 208 is rescinded. A copy of the notice on dynamic testing of manual safety belts is enclosed.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0862OpenMr. J. Richard Schlen, Schlen Body and Equipment Co., P. O. Box No. 229, Carllnville(sic), IL 62626; Mr. J. Richard Schlen Schlen Body and Equipment Co. P. O. Box No. 229 Carllnville(sic) IL 62626; Dear Mr. Schlen: This is in reply to your letter of September 22 to Mr. Ed Leysath o this Office regarding interpretations of FMVSS No. 108 on required mounting of marker lights on your dump trailers.; In answer to your first problem, a combination front clearance and sid marker lamp must meet the requirements for both, therefore, the full 180-degree visibility is required. If you determine that it is not practicable to mount the combination lamp in your alternate location, because of a greater possibility of damage, then separate lamps should be considered.; In answer to your second problem, because of the configuration and en use of your dump semi-trailers, your interpretation that rear clearance lamps mounted in a light box just below the rear trailer crossmember are as high as practicable is correct.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam4122OpenThe Honorable Ralph Davenport, South Carolina Legislature, P.O. 1301, Spartanburg, SC 20394; The Honorable Ralph Davenport South Carolina Legislature P.O. 1301 Spartanburg SC 20394; Dear Mr. Davenport: This is to follow up on your phone conversation with Stephen Oesch o my staff concerning the effect of Federal regulations on the tinting of motor vehicle windows. I hope the following discussion answers your questions.; Some background information on how Federal motor vehicle safety law and regulations affect the tinting of vehicle windows may be helpful. Our agency is authorized, under the National Traffic and Motor Vehicle Safety Act, to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. We have issued 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 (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; You first asked if the Federal motor vehicle safety standards apply t foreign vehicles sold in the United States. As with all our standards, Standard No. 205 applies to any new vehicle, whether made by a foreign or domestic company, manufactured for sale in the United States. Thus, no manufacturer or dealer is permitted to install solar films and other sun screen devices, such as the one described in your letter, in *new* vehicles without certifying that the vehicle continues to be in compliance with the light transmittance and other requirements of the standard. Violation of Standard No. 205 can result in Federal civil penalties of up to $1,000 for each violation. In addition, a manufacturer of a vehicle that does not comply with our standards is required to remedy any noncompliances in its vehicles.; You also asked how Federal law affects businesses that tinted th windows of used vehicles. After a vehicle is first sold to a consumer, modifications to a vehicle are affected by section 108(a)(2)(A) of the Vehicle Safety Act. That section prohibits commercial businesses from tampering with safety equipment installed on a vehicle in compliance with our standards. Thus, no dealer, manufacturer, repair business or distributor can install a sun screen device for the owner of the vehicle, if the device would cause the window not to meet the requirements of Standard No. 205. Violation of the section 108(a)(2)(A) can result in Federal civil penalties of up to $1,000 for each violation.; Section 108(a)(2)(A) does not affect vehicle owners, who may themselve alter their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, the owner may install sun screening devices regardless of whether the installation adversely affects the light transmittance. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from using sun screens in their vehicles.; If you need further information, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1320OpenJ. B. H. Knight, Rolls-Royce Motors Limited, Car Division, Crewe Cheshire CWI, 3PL England; J. B. H. Knight Rolls-Royce Motors Limited Car Division Crewe Cheshire CWI 3PL England; Dear Mr. Knight: This is in reply to your letter of October 16, 1973, requesting clarification of S7.2 of Federal Motor Vehicle Safety Standard No. 301 (9-1-75) (Docket No. 70-20, Notice 2).; As you are aware, a proposed amendment to Federal Motor Vehicle Safet Standard No. 301 (9-1-75) was published on August 20, 1973 with an anticipated September 1975 effective date (Docket No. 73-20, Notice 1). In the event that the proposed amendment of loading conditions is adopted, the present passenger car requirement, that the vehicle be at its GVWR during testing, will be superseded by the requirement that the passenger car be loaded 'to its unloaded vehicle weight plus its rated cargo and luggage capacity weight, secured in the luggage area, plus the weight of the necessary dummies.' under these specifications, rear sear occupant weight will not be a factor of the test load condition unless a specific test requirement calls for dummies to be placed in designated rear seating positions. The proposed amendment would also make it unnecessary to firmly fix the dummies to the vehicle as is presently the case under S7.2.; We have also noted your views on luggage capacity weight and ar placing your letter in Docket No. 73-20 as a comment to be considered.; If you require any further clarification, please do not hesitate to le us know.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam5363OpenMr. David Fabrycky 1633 W. Willeta St. Phoenix, AZ 85007; Mr. David Fabrycky 1633 W. Willeta St. Phoenix AZ 85007; "Dear Mr. Fabrycky: This responds to your letter about an aftermarke product you wish to manufacture. The product is a child safety seat buckle shield, which is intended to prevent a child from opening the buckle on a child restraint system. You state that your device would cover the buckle and prevent the child from gaining access to the pushbutton of a child seat buckle. To depress the pushbutton, the device requires that a latch be actuated and the cover pivoted away from the buckle. You indicated that the device requires 'manual dexterity to exert the forces in many directions simultaneously.' Although we understand your concern that young children not be able to easily unbuckle a child safety seat, we have reservations about devices that interfere with the unbuckling of the seats. I hope the following discussion explains those reservations and answers the questions in your letter about the effect of our regulations on your product. Our agency has the authority to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. We have exercised this authority to establish Safety Standard No. 213, 'Child Restraint Systems,' which applies to all new child restraint systems sold in this country. However, Standard 213 does not apply to aftermarket items for child restraint systems, such as your buckle shield. Hence, you are not required to certify that this product complies with Standard 213 before selling the product. Additionally, you are not required to get 'approval' from this agency before selling the buckle shield. NHTSA has no authority to 'approve' motor vehicles or motor vehicle equipment, nor do we endorse any commercial product. Instead, the National Traffic and Motor Vehicle Safety Act establishes a 'self- certification' process under which each manufacturer is responsible for certifying that its products meet our safety standards. The agency periodically tests vehicles and equipment items for compliance with the standards, and also investigates alleged safety-related defects. Although we do not have any standards that directly apply to your product, there are several statutory provisions that could affect it. Manufacturers of motor vehicle equipment such as your buckle shield are subject to the requirements in sections 151-159 of the Safety Act concerning the recall of products with defects related to motor vehicle safety. The agency does not determine the existence of safety defects except in the context of a defect proceeding, and thus is unable to say whether your product might or might not contain such a defect. However, the agency is concerned that people be able to easily and quickly operate a child safety seat buckle in an emergency. As the agency said in a rule on the force level necessary to operate child restraint buckles: The agency's safety concerns over child restraint buckle force release and size stem from the need for convenient buckling and unbuckling of a child and, in emergencies, to quickly remove the child from the restraint. This latter situation can occur in instances of post-crash fires, immersions, etc. A restraint that is difficult to disengage, due to the need for excessive buckle pressure or difficulty in operating the release mechanism because of a very small release button, can unnecessarily endanger the child in the restraint and the adult attempting to release the child. (50 FR 33722, August 21, 1985) It appears that your product could significantly increase the difficulty of using the buckle release and thus hinder a person attempting to release the belt in an emergency. In addition, use of your product could be affected by section 108(a)(2)(A) of the Safety Act. That section prohibits commercial businesses from knowingly tampering with devices or elements of design installed in an item of motor vehicle equipment, such as a child safety seat, in compliance with the Federal motor vehicle safety standards. In determining the effect of a buckle shield on a child seat's compliance with Standard 213, NHTSA would evaluate the performance of the seat with the buckle shield installed. Standard 213 specifies several elements of design with which a child restraint system is unlikely to comply if your buckle shield were installed. Section S5.4.3.5 of Standard 213 requires the pushbutton release for any buckle on a child restraint to have a minimum area for applying the release force. Since your device will completely cover the buckle when installed, the buckle shield would cause the child restraint to no longer comply with this requirement. That section also requires the buckle to release when a specified maximum force is applied. Your device will not allow the buckle to release when the force is applied because it will cover the buckle and require force to be applied 'in many directions simultaneously.' Your device would thus cause the child restraint to no longer comply with that requirement. Therefore, commercial establishments cannot legally install your device on customers' child safety seats. In addition, section S5.7 of Standard 213 requires each material used in a child restraint system to comply with the flammability resistance requirements of Standard 302, 'Flammability of Interior Materials.' If your buckle shield does not comply with the requirements of Standard 302, commercial establishments cannot legally install your device. The prohibition of section 108(a)(2)(A) does not apply to individual vehicle owners who may install or remove any items on child restraint systems regardless of the effect on compliance with Standard 213. However, our policy is to encourage child restraint owners not to tamper with or otherwise degrade the safety of their child restraints. I hope this information is helpful. If you have any further questions, please contact Ms. Deirdre Fujita of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting 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.