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 |
|---|---|
ID: nht71-4.23OpenDATE: 10/18/71 FROM: AUTHOR UNAVAILABLE; D. W. Toms; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: Secretary Volpe has asked me to reply to your letter of October 18, 1971, concerning the applicability of the National Traffic and Motor Vehicle Safety Act of 1966 in the territories and possessions of the United States. The Act and the Federal motor vehicle safety standards issued thereunder apply in Puerto Rico, the Virgin Islands, the Canal Zone, Guam, and American Samoa. Motor vehicles, including buses, manufactured for sale and imported into those areas must meet all applicable Federal motor vehicle safety standards. Only one standard applicable to buses, No. 103, Windshield Defrosting and Defogging Systems, specifically does not apply to buses manufactured for sale outside the Continental United States. There are no Federal standards applicable to school bus bodies, so that the wooden bodied buses in American Samoa, of which you spoke, are not prohited by the Act. School buses manufactured for sale in Puerto Rico are required, however, to have a warning light system. I HOPE THIS CLARIFIES THE MATTER FOR YOU. |
|
ID: nht72-3.24OpenDATE: 07/25/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: 5-J Manufacturing TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of June 20, 1972, requesting copies of Department of Transportation requirements regarding the manufacture of small boats, truck camper shells, camping trailers, and boat trailers. The NHTSA does have requirements regarding some of these components. All truck campers are required to conform to Motor Vehicle Safety Standard No. 205, "Glazing Materials," while those campers designed for mounting on incomplete vehicles (as distinguished from those mounted on pick-up trucks) that are manufactured after September 1, 1972, must conform to Motor Vehicle Safety Standard No. 206, "Door Locks and Door Retention Components." Camping and boat trailers must conform to Standard No. 108, "Lamps, Reflective Devices, and Associated Equipment." In addition, manufacturers of these products (campers, trailers, etc.) must certify that their products conform to the standards in the manner set forth in the Certification regulations (49 CFR Parts 567, 568). Information on how to obtain copies of NHTSA requirements is enclosed. We have referred your request for rules and regulations regarding the manufacture of small boats to the United States Coast Guard, and have requested that they respond directly to you. |
|
ID: nht70-2.10OpenDATE: 05/15/70 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: Fleet Cap'n Trailers, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of April 29, 1970, to Mr. Rodolfo A. Diaz, Acting Associate Director, Motor Vehicle Programs, concerning the location of rear lamps on various models of your trailers. From a review of the sketch attached to your letter, it appears that the tail, stop and turn signal lamps mounted on the trailer frame rearward of the fenders will meet the location requirements specified in Table IV of Federal Motor Vehicle Safety Standard No. 108. However, Standard No. 108, by reference to SAE Standard J588d, also re-requires that "--- visibility of the front turn signal to the front and the rear signal to the rear shall not be obstructed by any part of the vehicle throughout the photometric test angles for the lamps." The photometric test angles for turn signal lamps are specified in Table 2 of SAE Standard J575c. From your sketch it appears that the required visibility of the turn signal lamps, when mounted in the proposed location, would be partially blocked by the framework of the trailer. Mounting the lamps on the rear crossmember may therefore be necessary to provide the required unobstructed visibility. For your information I am enclosing copies of Standard No. 108, SAE Standard J588d and SAE Standard J575c. |
|
ID: 10906Open Mr. Ron Hooker Dear Mr. Hooker: This responds to your question about whether the State of Missouri has authority to promulgate regulations relating to the safety of motor vehicles powered by alternative fuels, particularly compressed natural gas (CNG). The short answer is that while Missouri is generally preempted in this area, it could issue its own more stringent safety standard for State-owned vehicles. Federal law will preempt a State law if (1) there is a Federal safety standard in effect, (2) the State law covers the same aspect of performance as that Federal standard, and (3) the State law is not identical to the Federal standard. Specifically, section 30103(b) of Title 49 of the United States Code states that (b) Preemption. - (1) When a motor vehicle safety standard is in effect under this chapter, a State or political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter. However, the United States Government, a State, or a political subdivision of a State may prescribe a standard for a motor vehicle or motor vehicle equipment obtained for its own use that imposes a higher performance requirement than that required by the otherwise applicable standard under this chapter. State safety standards applicable to CNG fuel system integrity are generally preempted by Federal law. The National Highway Traffic Safety Administration (NHTSA) has issued Federal motor vehicle safety standard (FMVSS) No. 303, Fuel system integrity of compressed natural gas vehicles. (59 FR 19659, April 25, 1994, copy enclosed). The Standard specifies frontal barrier and rear barrier crash tests conducted at 30 mph and a lateral moving barrier crash test conducted at 20 mph. The Standard applies to passenger cars, multipurpose passenger vehicles, trucks and buses that have a gross vehicle weight rating (GVWR) of 10,000 pounds or less and use CNG as a motor fuel. It also applies to school buses regardless of weight that use CNG as a motor fuel. The Standard takes effect September 1, 1995. Accordingly, after September 1, 1995, Missouri could only issue its own safety standard applicable to CNG vehicle fuel system integrity if the State safety standard is identical to FMVSS No. 303. The one exception to requiring such identical standards is that Missouri could prescribe a standard for motor vehicles obtained for its own use, provided the State law imposed a higher performance requirement than the level of performance prescribed by FMVSS No. 303. Thus, Missouri could issue its own more stringent safety standard for State-owned vehicles. NHTSA further notes that Missouri is free to issue safety standards applicable to the fuel system integrity of vehicles powered by other alternative fuels (e.g., liquid propane, hydrogen), since the agency has not issued any FMVSS applicable to other alternative fuels. I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw at this address or by phone at (202) 366-2992. Sincerely,
John Womack Acting Chief Counsel Enclosure ref:VSA d:6/8/95
|
1995 |
ID: nht89-1.55OpenTYPE: INTERPRETATION-NHTSA DATE: 03/29/89 FROM: CHESTER G. ATKINS -- MEMBER OF CONGRESS TO: NANCY BRUCE -- DIRECTOR OFFICE OF CONGRESSIONAL AFFAIRS UNITED STATES DEPARTMENT OF TRANSPORTATION TITLE: MRS. BLANCHE KOZAK 49 SORRENTO AVENUE METHUEN, MA 01844 ATTACHMT: ATTACHED TO LETTER DATED 06/09/89 FROM STEPHEN P. WOOD -- NHTSA TO BLANCHE KOZAK; REDBOOK A33 [2]; VSA 108 [A] [1] [A]; LETTER DATED 04/04/89 FROM NANCY L. BRUCE -- DOT TO CHESTER ATKINS -- HOUSE; LETTER DATED 09/26/88 FROM BLANCHE KOZAK TO BER RY FELRICE; LETTER DATED 10/16/79 FROM EDWIN P. RIEDEL; REPORT UNDATED; LETTER DATED 08/09/88 FROM BLANCHE G. KOZAK TO DEPARTMENT OF TRANSPORTATION TEXT: Dear Ms. Bruce: On behalf of my constituent, Blanche Kozak, I am enclosing a copy of letters which Mrs. Kozak sent last year to Barry Felrice, the Associate Administrator for Rulemaking for NHTSA and to the General Counsel of the DOT concerning the Cushman 404 vehicl e. As you will see from the enclosures, Mrs. Kozak's husband died following an accident in the Cushman 404 and she is interested in determining the regulatory status of this vehicle. Mrs. Kozak has not received a response to either of the enclosed lett ers. We would appreciate any assistance you could provide to prompt a response to these letters. Thank you in advance for your anticipated cooperation. If you need any additional information, please feel free to contact Josie Gump in my district office. Sincerely, Enclosure |
|
ID: nht73-5.30OpenDATE: 10/26/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 25, 1973, asking whether the fuel spillage measurement specified in Standard No. 301 is an average rate of one onunce per minute (your Item A) or an actual rate. (Your Item B) Your item B is correct. Fuel spillage shall not exceed one ounce per minute in any one of the fifteen minutes of the observed period. YOURS TRULY, NISSAN MOTOR CO., LTD. September 25, 1973 Lawrence Schneider Chief Council National Highway Traffic Safety Administration This is to ask your interpretation regarding the test procedures of MVSS 301 Fuel System Integrity published in Federal Register, Vol. 38, No. 160 (Docket No. 70-20) on August 20, 1973. We feel that the fuel spillage requirement following cessation of vehicle motion of S.5.4 has the following two meanings: A) The calculated fuel spillage rate. Total amount of fuel spillage (oz.) B) The measured fuel spillage rate every minute. All of the collected fifteen one-minute timed samples shall not exceed one ounce per minute. We would like to know which definition is correct understanding. Your prompt reply would be greatly appreciated. Very Truly Yours, Tatsuo Kato |
|
ID: nht69-2.14OpenDATE: 07/18/69 FROM: AUTHOR UNAVAILABLE; Robert Brenner; NHTSA TO: Ward School Bus Manufacturing Incorporated TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of May 28, 1969, in which you request approval of an alternative to the label locations specified in Section 367.4(c) of the Certification Regulations that will be effective as to vehicles manufactured on or after September 1, 1969. The label location, on the panel ovay the driver's window, as shown in your enclosed photograph is acceptable. Your cooporation is appreciated. |
|
ID: nht71-3.4OpenDATE: 05/17/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Tanaka and Walders TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of April 19, 1971, in which you discussed the difficulties that may be caused by State enforcement procedures that require a manufacturer to obtain State approval of products covered by Federal standards before he may sell the products in the State. Your letter was an amplification of the JAMA petition for reconsideration of Standard No. 209, submitted April 3, 1971. The NHTSA is giving careful consideration to the situation you have described. We intend to take action to alleviate the problem in the near future. |
|
ID: nht71-1.47OpenDATE: 01/08/71 FROM: R. H. COMPTON -- NHTSA; SIGNATURE BY CHARLES A. BAKER TO: A. Hammerstein TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of December 23, 1970, to the U. S. Department of Tranportation concerning the time when stop lamps will be required to meet Class A photometrics. The conflict between the requirements of paragraphs S4.1.1.6 and S4.1.1.7 has already been called to our attention, and will be clarified in an amendment to Standard No. 108 scheduled to be published in the Federal Register in the near future. It was not intended for the stop lamps to meet the Class A photometric values, nor are they required to, until January 1, 1973. |
|
ID: nht91-4.14OpenDATE: June 4, 1991 FROM: Debby Funk TO: The United States Department of Transportation TITLE: None ATTACHMT: Attached to letter dated 6-25-91 from Paul Jackson Rice to Debby Funk (A38; Std. 108) TEXT: I am writing to request that you send me information regarding any and all rules and restrictions regarding the display of lighted signs in vehicles. If such signs are not prohibited, I am particularly interested in regulations governing size, placement, color, luminosity, and power source (i.e. batteries, wire connections to either brake lights or cigarette lighter). I thank you in advance for your prompt reply. Your help and attention in this matter are greatly appreciated. |
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.