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: aiam2152OpenMr. Charles J. Calvin, President, Truck Trailer Manufacturer Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Charles J. Calvin President Truck Trailer Manufacturer Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Calvin: This responds to the Truck Trailer Manufacturer Association's Novembe 17, 1975, request that the NHTSA reconsider its opinion that modification of existing tank trailers to increase their volumetric capacity and length does not constitute manufacture of a new air-braked trailer that must comply with Standard No. 121, *Air Brake Systems*. This opinion appears in a letter of August 28, 1975, to Stainless Tank and Equipment, Inc.; The National Traffic and Motor Vehicle Safety Act (the Act) authorize the issuance of motor vehicle safety standards (15 U.S.C. S 1392(a)) and prohibits, among other things, the manufacture of a motor vehicle on or after the date any applicable standard takes effect unless the vehicle conforms to the standard, and is so certified (15 U.S.C. S 1397(a)(1)(A), 1403). With the 1974 Amendments, (15 U.S.C. S 1397(a)(2)(A)) no manufacturer, distributor, dealer, or repair business may perform modifications that render inoperative any device or element of design required by a standard. However, unless the modifications performed are so extensive as to constitute legally the manufacture of a new vehicle, the standards that continue to apply to a vehicle are those in effect at the time of its original manufacture, not those that may have come into effect at a later date.; The modification of a tank trailer to increase its volumetric capacit and length does not, in our view, constitute the manufacture of a new vehicle in the typical situation (about an 18-inch increase in length). For this reason, Standard No. 121 does not apply to existing vehicles that are modified in accordance with your description.; This response does not address the issue of compliance with Federa motor carrier regulations raised in your November 17, 1975, letter.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0495OpenMr. Ed Baringer, Manager, Penn-Ohio Chapter, 25 East Boardman Street, Youngstown, OH 44503; Mr. Ed Baringer Manager Penn-Ohio Chapter 25 East Boardman Street Youngstown OH 44503; Dear Mr. Baringer: In your letter of November 23, 1971, you asked how your members coul make sure that the seat belts they install in their trucks conform to the applicable motor vehicle safety standards. As far as the belts themselves are concerned, each belt made after the seat belt standard (No. 209) became effective in 1967 is required to (sic) marked with the year of manufacture. So long as the belt bears a date after 1967, it will have had to conform to the seat belt standard and your members should use the date as a guide in purchasing belts.; The provision of anchorages for the belts is a somewhat more comple problem. A new truck - manufactured after July 1, 1971 -is required to have anchorages for lap belts at all seating positions (and, in some cases, anchorages for shoulder belts). Although older trucks were sometimes provided with anchorages, many were not, and for these you will have to follow the location and instructions of Standard No. 210 in order to comply with the Motor Carrier Safety Regulations. Although the Motor Carrier Safety Regulations do not establish strength requirements for anchorages, their strength should be of concern to you and in this area you may have to rely on the manufacturer, rather than the dealer, for advice on reinforcement of the vehicle structure.; Our legal staff is centralized in Washington and there are no fiel representatives of the agency who could assist you in matters relating to the standards. As much as we would like to send someone to address your group, the workload of the upcoming months prevents such a trip. However, we have found that many questions can be satisfactorily answered by letter. If your group could assemble a detailed list of questions, we will try to answer them as fully as possible.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0180OpenMr. John Thomas, Staff Engineer, Motor Vehicle Safety, International Harvester Company, Motor Truck Division, P. O. Box 1109,Fort Wayne, IN 46801; Mr. John Thomas Staff Engineer Motor Vehicle Safety International Harvester Company Motor Truck Division P. O. Box 1109 Fort Wayne IN 46801; Dear Mr. Thomas: This is in reply to your letter dated June 19, 1969, in which yo request approval of an alternative to the specified certification label location in accordance with Part 367.4(c) of the regulations. Due to an oversight, your letter has not reached me until now, and I apologize for the delay in responding.; Your proposed label location for models MA-1200 and MA-1500 Metro, o the panel below the wing glass, as shown in your enclosed sketch, is approved.; Sincerely, Robert Brenner, Acting Director |
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ID: aiam5382OpenThe Honorable John A. Boehner Member, United States House of Representatives 5617 Liberty Fairfield Road Hamilton, Ohio 45011; The Honorable John A. Boehner Member United States House of Representatives 5617 Liberty Fairfield Road Hamilton Ohio 45011; Dear Congressman Boehner:: This responds to your letter of April 7 1994, to the Department of Transportation (DOT) on behalf of your constituents, John Cail Sr. and James Lipps of Eaton. Messrs. Cail and Lipps have requested your assistance in obtaining DOT 'approval and color code designation' for their 'Life Lites' system. This is a stop lamp system consisting of two 18-inch long 1/2-inch wide devices intended to be mounted on the front of a vehicle alongside the windshield pillars, to emit a light of either purple or coral. The system is activated with the rear stop lamps when the brakes are applied, and it is intended to warn observers to the front of a vehicle that the vehicle is braking. It 'could be mounted to most existing vehicles and could be readily incorporated into new car designs.' The National Highway Traffic Safety Administration (NHTSA)is the component of DOT that is responsible for motor vehicle safety under the National Traffic and Motor Vehicle Safety Act. The Act does not authorize NHTSA to 'approve' or disapprove safety inventions such as Life Lites. We do advise, however, whether such inventions are permitted under the Act and applicable regulations such as the Federal motor vehicle safety standards. The fact that a device may be permitted under NHTSA laws must not be interpreted as our approval or endorsement of it. The standard that applies to motor vehicle lighting is Standard No. 108 Lamps, Reflective Devices and Associated Equipment. Life Lites emitting either color may be installed as original equipment by the manufacturer, distributor, or dealer at the time a vehicle is sold to its first purchaser provided that it does not impair the effectiveness of any of the frontal lighting equipment required by Standard No. 108 such as headlamps and turn signals. The materials you enclosed show a color closeup newspaper photo of a Life Lite in operation, its relatively low output does not appear sufficient to impair headlamp effectiveness. There would be concern, however, if it were to distract attention from an operating turn signal and, in this sense, impair its effectiveness. However, the responsibility for determining whether supplemental original lighting equipment impairs the effectiveness of the required lighting equipment rests with the installer, and NHTSA will not question this determination unless it appears clearly erroneous. Life Lites that are sold in the aftermarket and intended for vehicles in use, are prohibited by the Act if their installation by a manufacturer, distributor, dealer, or motor vehicle repair business 'knowingly renders inoperative, in whole or part' the required motor vehicle lighting equipment. Though the words are different between the Act and Standard No. 108, in this instance we would equate partial inoperability with impairment of effectiveness and the same considerations would apply. However, the Act does not prohibit vehicle owners under any circumstances from installing Life Lites themselves if they are able to do so. But the legality of Life Lites of either color and under any scenario remains subject to the laws of any State in which the device is operated. We are unable to advise your constituents of the laws of the individual States, and suggest that they write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. Sincerely, John Womack Acting Chief Counsel; |
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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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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.