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: aiam0993OpenMr. Charles J. Simerlein, Engineering Liaison Manager, Rockleigh, NJ 07647; Mr. Charles J. Simerlein Engineering Liaison Manager Rockleigh NJ 07647; Dear Mr. Simerlein: This is in reply to your letter of November 29, 1972, concerning th method in which a load is to be 'secured in the luggage area' under the test procedures of Standard 208. I apologize for our delay.; The intent of S8.1.1(a) is to place the load in the luggage area i such a way that it stays there during the test. The standard does not specify the manner in which the load is secured. A manufacturer may secure it in any reasonable manner.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0646OpenMr. Gorou Utsunomiya, Chief, Liaison Engineer, Toyo Kogyo Detroit Office, 3841 Mystic Valley Dr., Bloomfield Hills, MI 48013; Mr. Gorou Utsunomiya Chief Liaison Engineer Toyo Kogyo Detroit Office 3841 Mystic Valley Dr. Bloomfield Hills MI 48013; Dear Mr. Utsunomiya: This is in response to your letter of March 16, 1972, in which you as whether the definition of 'unloaded vehicle weight' is the same as that for ''curb weight' plus optional parts,' and whether the definition of 'gross vehicle weight' is the same as that for 'maximum loaded vehicle weight.'; The two sets of definitions are expressed in substantially differen terms. The new terms, 'unloaded vehicle weight' and 'gross vehicle weight rating' are more general than the older ones. The newer terms also eliminate some ambiguities in the definitions based on 'curb weight,' such as just what is meant by 'standard equipment,' and whether other vehicle fluids besides fuel, oil, and coolant should be included. Further, GVWR is a rating, not necessarily identical to any scale weight although some constraints have been placed on it in our Certification regulations (S567.4(g)(3)).; Thus, although the two sets of definitions are somewhat similar i their application, they are different enough that each must be interpreted and used in its own terms.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0856OpenProfessor Ralph W. Zimmer, Assistant Professor, Department of Civil Engineering & Engineering Mechanics, Montana State University, Bozeman, MT 59715; Professor Ralph W. Zimmer Assistant Professor Department of Civil Engineering & Engineering Mechanics Montana State University Bozeman MT 59715; Dear Professor Zimmer: Thank you for your letter of September 6, 1972, and the suggestions fo improving motor vehicle safety.; The National Highway Traffic Safety Administration is aware of the hor problem described in your letter and recognizes that a driver's inability to quickly locate it can result in accidents, especially during panic situations. We have not issued any standard specifying the location of horn rim buttons or rings at this time, but we have initiated research to determine the best location and type of horn switches. Data from this research will be used for possible future rulemaking action.; We are preparing to issue in the near future a notice of propose rulemaking to amend Federal Motor Vehicle Safety Standard No. 108 'Lamps, Reflective Devices and Associated Equipment'. This notice will propose that stop lamps be separate from other rear lamps, and, if the proposal is adopted, simultaneous operation of the stop and hazard warning signals will then be possible.; The four-wheel drive recreational vehicle described in your letter i classified under the Federal motor vehicle safety standard as a multipurpose passenger vehicle, and some of our present safety standards are not applicable to it. We are however monitoring the type and frequencies of all types of accidents and, if it appears the applicability of these standards should be extended to multipurpose passenger vehicles, we will propose such amendments. Enclosed for your review and further information is a summary description of all the safety standards and their applicability, revised as of June 1972.; Most of the late model cars now have a self-cancelling feature on thei turn signals which has eliminated most of the problems described in your letter. Standard No. 108 mandates self- cancelling turn signals on most motor vehicles manufactured on or after January 1, 1973. We have no immediate plans to issue requirements for audible alarms in vehicles, but we do appreciate your comments. If future safety conditions should warrant, we will consider issuing such requirements.; Again, thank you for writing to us and, if we can be of any furthe service to you, please let us know.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam2519OpenMr. K. W. Schang, Director, Vehicle Safety Programs, American Motors Corp., 14250 Plymouth Road, Detroit, MI 48232; Mr. K. W. Schang Director Vehicle Safety Programs American Motors Corp. 14250 Plymouth Road Detroit MI 48232; Dear Mr. Schang: This is in response to your letter of November 24, 1976, requesting favorable response by the National Highway Traffic Safety Administration (NHTSA) to your petitions for reconsideration of the Part 581, *Bumper Standard*, requesting an effective date of September 1, 1979.; The NHTSA is continuing to examine the petitions submitted in respons to the publication of Part 581. On Tuesday, February 22, 1977, the NHTSA issued a Federal Register notice proposing to delay for 1 year, until September 1, 1980, implementation of the second phase of requirements under Part 581. This action was taken in response to petitions for reconsideration from Ford Motor Company and General Motors. I have enclosed a copy of the notice for your information. I want to assure you that every consideration is being given to the matters raised both in your petition and in your November 24, letter. The issues you have mentioned will, of course, be thoroughly addressed by notice in the Federal Register.; Sincerely, John W. Snow |
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ID: aiam0894OpenMr. Tatsuo Kato, Engineering Representative, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Tatsuo Kato Engineering Representative Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Kato: This is in reply to your letter of August 14, 1972, on the subject o the test dummy specifications of Standard No. 208. I apologize for our delay in replying.; The alignment procedures of S8.1.11 of the standard cause the head t be aligned so that its vertical axis is almost in the same plane as the dummy's back. The necks on most commercial dummies are made of rubber and are installed at such an angle that, as you noted, the specified head alignment cannot be maintained. To correct this misalignment, the necks must be adjusted by shims or other means so that the correct alignment can be maintained.; The center of gravity of the upper thorax is approximated by dimension C and D in Table I and Figure 1 of SAE Recommended Practice J963. The precise location may vary slightly from one dummy model to another due to variances in the distribution of mass in the thoracic area.; Truly yours, Richard Dyson, Assistant Chief Counsel |
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ID: aiam1416OpenMr. Thomas S. Pieratt, Truck Equipment & Body Distributors, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Truck Equipment & Body Distributors 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in reply to your letter of December 18, 1973, inquiring whethe a manufacturer would be an intermediate or final-stage manufacturer if he installs truck bodies or material handling devices (frequently final-stage manufacturing operations) but he expects that a later manufacturer will either extend the chassis frame or add a third axle. These additions are necessary to make the vehicle safe to operate.; In most cases, we would consider the manufacturer in question to be a intermediate manufacturer. Under the definitions of 'completed vehicle,' 'intermediate manufacturer,' and 'final-stage manufacturer' (49 CFR 568.3), the manufacturer would be a final-stage manufacturer only if, at the time he completes his manufacturing operation, the vehicle requires no further manufacturing to perform its intended function, unless the further manufacturing involves only 'readily-attachable components.'; In the case you present, the vehicle cannot perform its intende function unless further modifications are made. That it be able to perform its intended function implies that it be able to do so safely. The answer ultimately depends, therefore, on whether the additions that will be made to the vehicle involve only readily attachable components. We would not generally consider either an extension of the chassis or the addition of a third axle to involve only readily attachable components.; Of course, in those cases where no further modifications are necessar for safe operation, the crane or body installer will be the final-stage manufacturer.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1212OpenMr. R. D. Shepard, Staff Engineer-Electrical & Safety, Diamond Reo Trucks, Inc., 1331 S. Washington, Lansing, MI 48920; Mr. R. D. Shepard Staff Engineer-Electrical & Safety Diamond Reo Trucks Inc. 1331 S. Washington Lansing MI 48920; Dear Mr. Shepard: This is in reply to your letter of July 19, 1973, asking whether a rea 'light signalling' switch may be installed on your vehicles.; As I understand your letter, the switch and circuitry in questio provide automatic flashing of side markers, clearance, tail, and identification lamps. Wiring of this nature, whether installed by the incomplete, intermediate, or final stage manufacturer would violate S4.6(b) of Standard No. 108 (formerly S4.5.8(b)). You are correct in saying that a switch and circuit may be furnished by manufacturers of truck-tractors, and incomplete vehicles for flashing only the side markers, and 'that trailer manufacturers and subsequent vehicle manufacturers shall be responsible for the electrical circuitry to insure that marker lamps are independent from clearance, tail, and identification lamps.' Of course, wiring these lamps to the same on-off switch would not violate the standard provided there is no flasher in the circuit.; You also ask 'who assumes the responsibility for older trailers whic will not have marker lamps on an independent circuit.' The person completing the circuitry on a trailer is responsible for compliance to standards in effect when the trailer is completed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0763OpenMr. J. Stephen Shuckra, Treasurer, Brighton Truck & Equipment Sales, Inc., 2654 West Henrietta Road, Rochester, NY 14623; Mr. J. Stephen Shuckra Treasurer Brighton Truck & Equipment Sales Inc. 2654 West Henrietta Road Rochester NY 14623; Dear Mr. Shuckra: This is in reply to your letter of June 20, 1972, asking severa questions regarding truck certification by final-stage manufacturers. We have repeated your questions below, responding to each.; >>>1. When is the progressive manufacturing report for each vehicl required to be filed?; You appear to be referring to 'incomplete vehicle documents,' which ar furnished by incomplete and intermediate manufacturers to final-stage manufacturers. These documents are not required to be filed, but are to be used by the final-stage manufacturer as a basis for his certification of the completed vehicle. We suggest you save these documents, however, should it be necessary for you to show that you exercised due care in completing and certifying a vehicle.; 2. If we sell a tractor cab and chassis upon which the customer is t install a fifth wheel, who is the final manufacturer? How? And when?; In this case, the customer is the final-stage manufacturer and bear the responsibility for certification (the regulations provide otherwise in the exceptional case where the incomplete vehicle manufacturer assumes this responsibility). If you do no more than sell the incomplete vehicle as it is delivered to you, you may meet your responsibilities under the regulations by forwarding to the customer the incomplete vehicle documents which you receive. Certification by the customer should be accomplished by affixing the required label containing the information specified in section 567.4 of the regulations, at the time of the installation of the fifth wheel.; 3. If we sell a cab and chassis for a van body upon which the custome plans to transfer a used body, who must make final certification, how and when?; The answer to this question is essentially the same as that to questio 2.; 4. Are the customers required to return vehicles to us afte installation of fifth wheel or body for us to issue the final sticker?; No. A customer who completes the vehicle is responsible for affixin the required label.<<<; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0758OpenMr. Chester R. Ely, President, Mercury Fabricators, 8335 Atlantic Boulevard, Cudahy, CA, 90201; Mr. Chester R. Ely President Mercury Fabricators 8335 Atlantic Boulevard Cudahy CA 90201; Dear Mr. Ely: This is in reply to your letter of June 20, 1972, in which you as whether Motor Vehicle Safety Standards Nos. 206 (Door Locks and Door Retention Components) and 302 (Flammability of Interior Materials) apply to aluminum sleeper cabs which you manufacture for what appears to be installation on truck tractors.; Each motor vehicle safety standard is by its terms applicable t specific types of motor vehicles and motor vehicle equipment. Each vehicle or item of equipment to which a standard applies must conform to the standard until its first purchase by a user. Components which are incorporated into vehicles before their first purchase are considered to be part of the vehicle, and as a practical matter must conform to all standards applicable to it.; Standard No. 302 becomes effective September 1, 1972, and applies t trucks, which includes truck tractors. If a sleeper cab you manufacture is incorporated into a truck before its first purchase by a user, then it must conform to the standard. Moreover, the components to which the standard applies (paragraph S4.1) include mattress covers, and if you determine the standard applies under the criteria we have provided, mattress covers which you furnish must conform to the standard. You indicate you have tested the flammability of the cab utilizing a torch. While you may test for conformity to the standard in any way you choose, whether or not your product conforms to the standard will be determined by NHTSA utilizing the test procedures specified in the standard. Manufacturers who utilize procedures different from those in the standard should take care to correlate the results they obtained to those that would be obtained using the standard's procedures.; Standard No. 206 also applies to trucks, and will become effective fo all side doors leading to passenger compartments on September 1, 1972. Consequently, if the sleeper cabs you manufacture are incorporated into trucks before their first purchase the sleeper cabs must conform to Standard No. 206.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0756OpenMr. Chester R. Ely, President, Mercury Fabricators, 8335 Atlantic Boulevard, Cudahy, CA 90201; Mr. Chester R. Ely President Mercury Fabricators 8335 Atlantic Boulevard Cudahy CA 90201; Dear Mr. Ely: This is in reply to your letter of June 20, 1972, in which you as whether Motor Vehicle Safety Standards No. 206 (Door Locks and Door Retention Components) and 302 (Flammability of Interior Materials) apply to aluminum sleeper cabs which you manufacture for what appears to be installation on truck tractors.; Each motor vehicle safety standard is by its terms applicable t specific types of motor vehicles and motor vehicle equipment. Each vehicle or item of equipment to which a standard applies must conform to the standard until its first purchase by a user. Components which are incorporated into vehicles before their first purchase are considered to be part of the vehicle, and as a practical matter must conform to all standards applicable to it.; Standard No. 302 becomes effective September 1, 1972, and applies t trucks, which includes truck tractors. If a sleeper cab you manufacture is incorporated into a truck before its first purchase by a user, then it must conform to the standard. Moreover, the components to which the standard applies (paragraph S4.1) include mattress covers, and if you determine the standard applies under the criteria we have provided, mattress covers which you furnish must conform to the standard. You indicate you have tested the flammability of the cab utilizing a torch. While you may test for conformity to the standard in any way you choose, whether or not your product conforms to the standard will be determined by NHTSA utilizing the test procedures specified in the standard. Manufacturers who utilize procedures different from those in the standard should take care to correlate the results they obtained to those that would be obtained using the standard's procedures.; Standard No. 206 also applies to trucks, and will become effective fo all side doors leading to passenger compartments on September 1, 1972. Consequently, if the sleeper cabs you manufacture are incorporated into trucks before their first purchase the sleeper cabs must conform to Standard No. 206.; Yours truly, Richard B. Dyson, Assistant 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.