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: aiam2447OpenMr. Byron Crampton, Truck Body and Equipment Association, 5530 Wisconsin Ave., Suite 1220, Washington, D.C. 20015; Mr. Byron Crampton Truck Body and Equipment Association 5530 Wisconsin Ave. Suite 1220 Washington D.C. 20015; Dear Mr. Crampton: This responds to the Truck Body and Equipment Association's November 8 1976, question whether any provision of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other than Passenger Cars*, prohibits the certification of a vehicle following the addition of an axle system (typically known as a 'tag' or 'pusher' axle) that is not equipped with tires or rims at the time of sale and delivery to the first purchaser for purposes other than resale.; The answer to your question is no. The requirement of S5.1.1 tha '...each vehicle equipped with pneumatic tires for highway service shall be equipped with tires that meet [specified requirements]...' prohibits the installation of tires that do not meet certain performance requirements, but it is not a requirements that tires be fitted to every axle of a vehicle prior to certification and sale.; I would like to point out that S567.4(g) (4) of Part 567 *Certification*, requires that a gross axle weight rating be assigned to each axle system. Section S5.1.2 of Standard No. 120 specifies that the GAWR be not more than the sum of the maximum load ratings of the tires fitted to the axle in question. While the agency interprets Standard No. 120 to permit the assignment of a GAWR on the basis of tires listed on the certification plate for that GAWR, the assignment of an arbitrarily high (or low) GAWR for purposes such as avoiding a Federal motor vehicle safety standard (such as Standard No. 121, *Air Brake Systems*), would constitute a violation of S 108(a) (1) (D) of the National Traffic and Motor Vehicle Safety Act:; >>> S108(a) (1) No person shall (A) ........... (c) Fail to issue a certificate required by section 114 of this title or issue a certificate to the effect that a motor vehicle or item of motor vehicle equipment conforms to all applicable Federal motor vehicle safety standards, if such person in the exercise of due care has reasons to know that such certificate is false or misleading in a material respect,..............<<<; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5228OpenMr. Frank Millar 1841 Shady Brook Drive Thousand Oaks, CA 91362; Mr. Frank Millar 1841 Shady Brook Drive Thousand Oaks CA 91362; Dear Mr. Millar: This responds to your letter concerning Federal Moto Vehicle Safety Standard No. 105, Hydraulic Brake Systems, and Society of Automotive Engineers (SAE) Recommended Practice J201. I apologize for the delay in our response. You asked about the significance of the two documents for manufacturers and consumers. You also asked whether you are correct in interpreting section S5.2.1 of Standard No. 105 as requiring the parking brake of a Toyota Camry with a standard (stick shift) transmission to hold the car stationary on a hill with a 30 percent grade in both forward and reverse directions for five minutes. Your questions are addressed below. By way of background, the National Traffic and Motor Vehicle Safety Act authorizes the National Highway Traffic Safety Administration (NHTSA) to issue safety standards for new motor vehicles and items of motor vehicle equipment. All motor vehicles and items of motor vehicle equipment manufactured or imported for sale in the United States must comply with all applicable safety standards. Standard No. 105 is one of the safety standards issued by NHTSA. The standard specifies requirements for hydraulic service brake systems and associated parking brake systems, for the purpose of ensuring safe braking performance under both normal and emergency situations. The standard applies to passenger cars, multipurpose passenger vehicles, trucks, and buses with hydraulic service brake systems. Manufacturers must ensure that each new vehicle complies with each applicable requirement of the standard. The standard specifies the specific test conditions under which each performance requirement must be met. You asked the agency to confirm your understanding that section S5.2.1 of Standard No. 105 requires the parking brake of a Toyota Camry with a standard transmission to hold the car stationary on a 30 percent grade for five minutes in both forward and reverse directions. Section S5.2.1 reads as follows: Except as provided in S5.2.2, the parking brake system on a passenger car . . . shall be capable of holding the vehicle stationary (to the limit of traction on the braked wheels) for 5 minutes in both a forward and reverse direction on a 30 percent grade. Section S5.2.1 thus applies to all passenger cars, except as provided in S5.2.2. The alternative requirement set forth in S5.2.2 is only available for certain vehicles with a transmission or transmission control which incorporates a parking mechanism. Vehicles with standard transmissions do not typically have such a parking mechanism. Assuming that a Toyota Camry does not have a parking mechanism, it would be required to meet the requirements of S5.2.1. I note that, even assuming that a vehicle meets the requirements of S5.2.1, it would not follow that the parking brake system would hold the vehicle stationary on a 30 percent grade under all real world driving conditions. As indicated above, Standard No. 105 specifies specific test conditions under which its performance requirements must be met. In the case of the standard's parking brake requirements, the specified test conditions include such things as control force and test surface. Also, the requirement only applies to the limit of traction on the braked wheels. Thus, if a 30 percent grade has a slippery surface, the vehicle might slide down the grade even though its parking brake system held the wheels locked. Finally, the requirement applies only to new vehicles and not used ones. You also asked the significance of SAE J201 to manufacturers and consumers. The Society of Automotive Engineers is an independent, non-governmental group. In some cases, NHTSA has incorporated portions of that organization's recommended practices into its safety standards. Since the agency has not done so with SAE J201, that recommended practice does not have any significance to the Federal motor vehicle safety standards. NHTSA can only comment on the significance of its own standards and regulations and not on ones issued by other organizations or agencies. Therefore, we suggest that you contact SAE concerning the significance of SAE J201. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact David Elias of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2017OpenMr. James R. Greco, Technical Director, National Solid Wastes Management Association, 1730 Rhode Island Avenue, N.W., Washington, DC 20036; Mr. James R. Greco Technical Director National Solid Wastes Management Association 1730 Rhode Island Avenue N.W. Washington DC 20036; Dear Mr. Greco: This responds to the National Solid Wastes Management Association' July 29, 1975, question whether Standard No. 121, *Air Brake Systems*, or other Department of Transportation regulations require a vehicle operator to maintain and not disconnect brake components used in satisfaction of the standard. You state that you are already aware of operator responsibilities to meet the regulations of the Bureau of Motor Carrier Safety and those promulgated by State and local governments.; Section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safet Act of 1966 (15 U.S.C. 1397(a)(1)(A)) specifies in part that no person shall sell or introduce in interstate commerce a vehicle which does not comply with applicable standards in effect on the date of manufacture. Section 108(b)(2) provides that S 108(a)(1)(A) does not apply after the first purchase for purposes other than resale. The general effect of these provisions is that the brake system must comply and not be disconnected prior to its first retail sale. Section 108(a)(2)(A) provides that no manufacturer (sic) distributor, dealer, or motor vehicle repair business shall knowingly render inoperative a device installed in compliance with an applicable safety standard. Taken together, these provisions do not require the vehicle operator to maintain or not render inoperative a safety system after the first retail purchase. This agency does not recommend disconnection of elements of a brake system, however, in view of the probable adverse effect on handling not intended by the vehicle designer and engineer.; Other than the regulations of the Bureau of Motor Carrier Safety, o which you are aware, no regulations of the Department of Transportation require the maintainence (sic) or prohibit the disconnection of systems installed in satisfaction of motor vehicle safety standards.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0883OpenMr. John L. McLaughlin, Registrar, Department of Motor Vehicles, Division of Registration, P.O. Box 1319, Sacramento, CA 95806; Mr. John L. McLaughlin Registrar Department of Motor Vehicles Division of Registration P.O. Box 1319 Sacramento CA 95806; Dear Mr. McLaughlin: This is in reply to your letter of September 14, 1972, on the subjec of potential conflict between the California statute regulating passenger car bumpers and Federal Motor Vehicle Safety Standard No. 215, Exterior Protection.; On October 20, 1972, the President signed into law the Motor Vehicl Information and Cost Savings Act (P.L.92-513). One effect of this act will be to allow a State bumper standard that relates to property damage to coexist with a Federal safety standard if it is is not in conflict with' the Federal standard.; We do not find that there is a 'conflict' between the Californi statute and the Federal standard with respect to the language underlined in your letter. As a practical matter, the difference between the SAE J-850 test barrier specified by California and the fixed collision barrier specified in our standard is slight. Most test barriers will conform to the significant aspect of both specifications. This would not appear to be the degree of difference that could be termed a 'conflict' under the new Act.; Please advise us if you have further questions on this subject. Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam1791OpenMr. Colin Ham, Service Engineer, Jensen Motors, Incorporated, 19200 Susana Road, Compton, CA 90221; Mr. Colin Ham Service Engineer Jensen Motors Incorporated 19200 Susana Road Compton CA 90221; Dear Mr. Ham: This is in reference to your defect notification and remedy campaig (NHTSA No. 75-0004), concerning throttle cables on some 1974 Interceptors which may bind.; The letter which you have sent to the owners of the subject vehicle does not entirely meet the requirements of section 153 of the 1974 amendment to the National Traffic and Motor Vehicle Safety Act of 1966 and 49 CFR Part 577, 'Defect Notification.' The provisions of the amendment concerning notification and remedy requirements became effective on December 26, 1974. Unless mailing of the owner notification letters was begun prior to December 26, 1974, the provisions of section 153 should have been followed.; Your letter does not provide an adequate evaluation of the risk t motor vehicle safety reasonably related to the defect, as required by section 153(a)(2) and 49 CFR S 577.4(d). The possible consequences of a throttle sticking in the open position, such as vehicle crash, should have been given. Owners should also have been informed that they may write to the Administrator, National Highway Traffic Safety Administration, Washington, D.C. 20590, in the event that their dealer fails or is unable to remedy the defect without charge. This is required by section 153(a)(6). Finally, the last sentence in your third paragraph, beginning, '[H]owever, there have not been any reported instances . . .' must be deleted. We consider this statement to be a disclaimer and prohibited under 49 CFR S 577.6.; It is therefore necessary that you revise the notification letter an send a copy of the revised letter to this office and to each person registered under State law as the owner of an involved vehicle. Those owners whose vehicles have already been corrected at this time, however, need not be renotified. The revised letters should be sent by first class mail as specified by section 153(c)(1).; Copies of the 1974 amendment to the Act and 49 CFR Part 577 ar enclosed. If you desire further information, please contact Messrs. W. Reinhart or James Murray of this office at (202) 426-2840.; Sincerely, Andrew G. Detrick, Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam4069OpenMr. Hans W. Metzger, 6326 E. Turquoise Avenue, Scottsdale, AZ 85253; Mr. Hans W. Metzger 6326 E. Turquoise Avenue Scottsdale AZ 85253; Dear Mr. Metzger: Thank you for your letter of October 14, 1985, asking several question about Standard No. 208, *Occupant Crash Protection*. I hope that the following discussion answers your questions.; You first asked for a clarification of S4.1.3.1.2. That sectio provides that a manufacturer must equip a specific amount of its vehicles manufactured on or after September 1, 1986, and before September 1, 1987, with automatic restraints. The amount must not be less than 10 percent of the average annual production of passenger cars manufactured for sale in the United States during the period September 1, 1983, to August 31, 1986 (the base period).; You explained that your client did not produce any vehicles for th U.S. during one year of the base period (September 1, 1983 - September 1, 1984). For the other two years of the base period, your client produced a limited number of vehicles for sale in the U.S. You asked whether in calculating the average yearly production for the base period, it is correct for your client to use zero for the production between September 1, 1983 and August 31, 1984, and the actual production figures for two subsequent years.; The three year base period addresses a situation where a manufacture has produced vehicles for sale in the U.S. in each of those years. The purpose of averaging the production is to ensure that the calculation of the percentage of a manufacturer's passenger cars that must comply with the automatic restraint requirements is based on a production figure which is representative of the manufacturer's typical production. In the case of a manufacturer who has produced vehicles for two of those years, it would defeat the purpose of the rule to allow the manufacturer to lower artificially the number of vehicles which must comply with the automatic restraint requirement by counting its production as zero for one of the base years. Thus, in a situation where a manufacturer has only two years of production, the manufacturer should calculate its base period average based on the number of vehicles produced during those two years.; To provide manufacturer's with additional flexibility in calculatin the number of passenger cars which must be equipped with automatic restraints, NHTSA proposed, on April 12, 1985 (50 FR 14589), an amendment to Standard No. 208 which would give manufacturers the option of using either a three year average or the actual production for the model year in question. We expect to issue shortly a final rule on this subject.; You also asked for another clarification of S4.1.3.1.2. You asked i the required number of vehicles can be produced anytime (sic) between September 1, 1986 and August 31, 1987. S4.1.3.1.2 does not require that the automatic restraints be installed at any specific time during that period. Thus, you are correct that the installation of automatic restraints does not have to be evenly distributed throughout that 12 month interval.; I hope this information is of assistance to you. If you have an further questions, please let me know.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3256OpenMr. Frank J. Douthitt, Douthitt, Mitchell & Paul, P.O. Box 549, 201 N. Bridge Street, Henrietta, TX 76365; Mr. Frank J. Douthitt Douthitt Mitchell & Paul P.O. Box 549 201 N. Bridge Street Henrietta TX 76365; Dear Mr. Douthitt: This responds to your March 19, 1980, letter asking whether it is lega for a manufacturer to build a chassis that would normally have a high gross axle weight rating (GAWR) while continuing to certify the combined axle and chassis to a lower GAWR and gross vehicle weight rating (GVWR). The answer to your question is yes.; The chassis-cab manufacturer and the final-stage manufacturer whe certifying the proper GVWR and GAWR must consider the entire vehicle and its capacity to sustain the load for which it is designed. Therefore, if a manufacturer installs a heavy axle but does not reinforce the frame to correspond with the heavier axle, it must select a GVWR that reflects the capacity of the weaker frame rather than the stronger axle. The GAWR can be any amount appropriate for a given axle without regard to the vehicle's GVWR, provided the sum total of the Gross Axle Weight Ratings (GAWR) is not less than the Gross Vehicle Weight Rating (GVWR).; Your problem arises because the contract for purchase of th chassis-cab specified only the GAWR without insisting that the GVWR be similarly increased. This is entirely a private contractual matter and no Federal regulation of which we are aware has been violated.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4593OpenThe Honorable Leon E. Panetta House of Representatives Washington, DC 20515; The Honorable Leon E. Panetta House of Representatives Washington DC 20515; "Dear Mr. Panetta: This letter responds to your inquiry on behalf o your constituent, Mr. Botelho. You asked whether Federal regulations require mirrors to be placed on the right side of vehicles and whether such mirrors must be convex in nature. Mr. Botelho expressed his objection to requiring convex mirrors, because he believes convex mirrors distort images and cause objects to appear further away than they actually are. I am pleased to have this opportunity to explain this requirement and its background for you. Standard No. 111, Rearview Mirrors (49 CFR /571.111, copy enclosed)) establishes performance and location requirements for the rearview mirrors installed in new vehicles. Specifically, a passenger car whose inside rearview mirror does not meet the field of view requirements of section S5.1.1 must have an outside mirror on the passenger side of either unit magnification or a convex mirror. In a September 2, 1982 final rule amending Standard No. 111, the National Highway Traffic Safety Administration (NHTSA) explained that convex mirrors offer safety benefits by providing an expanded field of view to the rear, thereby reducing the need for the driver to turn around to view the rear directly. On the other hand, some users of convex mirrors that were used to the images shown by conventional plane mirrors incorrectly perceived that the object shown in the convex mirror was further to the rear than it actually was. Additionally, some users of convex mirrors experienced double vision, eyestrain, and nausea. After considering these potential advantages and disadvantages, NHTSA amended Standard No. 111 so that it does not require any vehicle to be equipped with convex mirrors, but it permits the use of convex mirrors on the passenger side of cars and light trucks, provided that the convex mirror meets certain additional requirements. The additional requirements applicable to convex mirrors on the passenger side of cars and light trucks are: 1. A maximum radius of curvature for the convex mirror. This limits the range of convexities to which drivers will be exposed. It also ensures that the field of view will be noticeably greater than for a plane mirror. 2. A minimum radius of curvature for the convex mirror. This ensures that the image size in the convex mirror will be adequate and distortion will not be excessive. 3. A stringent maximum permissible variation in the radius of curvature over the surface of the convex mirror. This requirement, which is more stringent than the European requirement in this area, also ensures that convex mirrors will have low distortion. 4. A warning etched on the convex mirror that objects shown in the mirror are closer than they appear. This requirement ensures that the driver who may not be familiar with convex mirrors will not be misled by the image size of the convex mirror and the apparent distance to the object. Hence, we agree with Mr. Botelho that the areas he has identified are potential problems unique to convex mirrors. However, our standard includes special requirements for convex mirrors to minimize the potential problems identified by Mr. Botelho and other potential problems that were identified in research studies of convex mirrors. We are not aware of any data showing that convex mirrors that comply with those special requirements present any unacceptable problems for drivers. I hope this information is helpful. If you have any further questions or need any additional information on this subject, please let me know. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam4439OpenArt Look, Marketing Executive Burke Communication Industries 1165 North Clark Street Chicago, IL 60610; Art Look Marketing Executive Burke Communication Industries 1165 North Clark Street Chicago IL 60610; "Dear Mr. Look: Your letter of October 30, 1987, addressed t Administrator Diane Steed, was referred to me for reply. You are apparently seeking this Department's approval of your product which you describe as a new warning device for stopped motor vehicles. As explained below, we do not provide approvals for products. Your product is made of inflatable plastic material that you describe as 'flexible and extremely durable.' When a user inflates your device, the product takes the shape of a cone standing about 18' high. The pictures you enclose indicate that the inflatable part of the cone has three broad alternating stripes. Two of the stripes are orange, and a 6' 'reflective' white stripe is sandwiched between them. Your cone sits on a non-inflatable, spherical, black base filled with 'approximately' 3 lbs. of sand. You state that your device has many advantages over the warning device currently specified in Federal Motor Vehicle Safety Standard 125, Warning Devices. Among the advantages you list are that your device is 'more visible at night, up to 1,000 ft. away,' that it '(is) not affected by winds up to 50 MPH,' and that if struck, it 'will return to an upright position' without damaging the vehicle involved. You state your company's intention to package your device in a corrugated container with three inflatable cones to a kit, including both a 'new-type double-action hand pump' and instructions for proper use of your device. Let me begin with some general information about this agency. The National Highway Traffic Safety Administration (NHTSA) is an agency of the Department of Transportation, and has authority under the National Traffic and Motor Vehicle Safety Act (the Safety Act) to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. However, NHTSA does not approve nor certify motor vehicles or motor vehicle equipment, or endorse any commercial product. Instead, the Safety Act establishes a 'self-certification' process under which each manufacturer is required to certify that its products meet all applicable safety standards issued by this agency. Periodically, NHTSA conducts tests to determine whether vehicles or equipment comply with these standards, and may investigate alleged safety-related product defects. One of the safety standards issued by this agency is Standard 125, Warning Devices, which sets uniform performance requirements for certain devices that are designed to be carried in a motor vehicle and used when needed to warn approaching traffic when the vehicle is disabled and stopped in or by the side of the road. The Standard applies to any such device that does not have a self-contained energy source (such as a battery). Your product falls under this Standard. Thus, it must meet the requirements of Standard 125, such as those on configuration, color, and reflectivity. Failure to comply with a standard renders the manufacturer subject to a civil penalty of $1,000 for each violation and a maximum penalty of $800,000 for a series of violations. In addition, the Safety Act requires a manufacturer to recall and remedy or replace a noncomplying item of motor vehicle equipment. As the above discussion suggests, you do not need approval from NHTSA or any other agency in the Department of Transportation to market your product. However, you do need both to ensure that your product meets Standard 125's requirements and to certify compliance. Our preliminary review of your product indicates that you may not be able to make that certification. For example, it appears that your product may not comply with the color, reflectivity, configuration, and stability requirements of Standard 125. If your product fails to meet these or other Standard 125 requirements, you cannot legally market it as a warning device. I hope you find this response helpful. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam0929OpenMrs. Katherine C. Little, Edgewood Motorcycle Shop, 1711 Pulaski Highway, Edgewood, MD 21040; Mrs. Katherine C. Little Edgewood Motorcycle Shop 1711 Pulaski Highway Edgewood MD 21040; Dear Mrs. Little: This is in reply to your letter of November 30, 1972, asking if yo have to maintain a record of the tires you sell and register or is it sufficient to mail the requested information to the tire manufacturer or the tire manufacturer's designee.; Under Part 574.8 of the Tire Identification and Record Keepin regulation (49 CFR Part 574) a tire dealer is recorded to submit the required information to the tire manufacturer or his designee but is not required to keep a separate record of the tires sold.; Sincerely, David Schmeltzer, Assistant 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.