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: nht78-2.48OpenDATE: 05/23/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: The Johnson Manufacturing Co. TITLE: FMVSS INTERPRETATION TEXT: This responds to Johnson Manufacturing's May 4, 1978 request for confirmation that the requirement in Standard No. 121, Air Brake Systems, that reservoirs "withstand" specific pressure does not require testing of a multi-compartment reservoir compartment-by-compartment. Your understanding of the "withstanding" requirement in S5.1.2.2 and S5.2.1.3 is correct. Although the agency sought to clarify that compartment-by-compartment testing was the proper interpretation of this requirement (42 FR 64630; December 27, 1977), problems with the interpretation resulted in its withdrawal (43 FR 9149; March 6, 1978) and adherence to the existing interpretation that there be no rupture or permanent circumferential deformation of the reservoir. Under this interpretation only the circumference of the outer reservoir shell is measured, and internal baffles are not stressed by separate compartment-by-compartment testing. |
|
ID: nht74-3.21OpenDATE: 10/10/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Joseph Lucas North America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This responds to your letter of September 30, 1974, enclosing sample brake hose assemblies and requesting approval of Girling's labeling and banding techniques to meet the requirements of Federal Motor Vehicle Safety Standard No. 106-74, Brake Hoses, for labeling brake hoses and brake hose assemblies. The NHTSA interprets a band as a label which encircles the hose completely and attaches to itself. To constitute labeling at all, of course, the band must be affixed to the hose in such a manner that it cannot easily be removed. From this discussion, you should be able to determine the compliance of your labeling method with the standard. The NHTSA does not approve specific designs in advance because the material, installation method, and underlying material can significantly affect the quality of specific design. |
|
ID: nht73-2.40OpenDATE: 02/23/73 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: The Gates Rubber Company COPYEE: BRAD MARKS; EDWARD B. FINCH -- FTC; MR. PESKOE TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of January 24, 1973, inquiring what NHTSA would consider to be an appropriate generic name for Dupont's Fiber B. The approval of generic names of cord materials is under the jurisdiction of the Federal Trade Commission. We understand that agency has issued a temporary approval with regard to this material, and that a further petition is currently under review. For purposes of conformity to Standard No. 109 we will, of course, accept any generic name approved by the Federal Trade Commission. If you desire further information regarding this matter, you may write to Mr. Edward B. Finch, Assistant Director for Textiles and Furs, Federal Trade Commission, Washington, D. C. 20580. |
|
ID: nht73-3.12OpenDATE: 01/16/73 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: General Motors Technical Center TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of January 10, 1973, in which you asked whether State "user laws" that prohibit the sale or operation of a motor vehicle without seat belts would be preempted by Standard 208, Occupant Crash Protection, to the extent that the standard allows vehicles to be manufactured with other types of restraint. The position of this agency is that section 103(d) of the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1392(d), requires State laws or rules that have the effect of regulating vehicle design or equipment to be identical to any Federal motor vehicle safety standards governing the same aspects of performance, whether the State rules are phrased as regulating manufacture, sale, or operation. |
|
ID: nht75-6.20OpenDATE: 03/21/75 FROM: BYRON CRAMPTON -- TRUCK BODY AND EQUIPMENT ASSOCIATION MANAGER OF ENGINEERING SERVICES TO: CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 08/19/75 EST, FROM RICHARD B. DYSON TO BYRON CRAMPTON; N40-30; OPINION FILE, STANDARD 108 TEXT: Dear Sir: Recently several members of the Truck Body and Equipment Association have raised questions concerning state versus federal motor vehicle lighting requirements. The vehicle in question is a multipurpose passenger vehicle less than eighty (80) inches wide, equipped with a raised roof. Our question is as follows: Can a state require a motor vehicle to be equiped with lights not required under FMVSS #108? Thanking you in advance for your help, I am, Very truly yours, |
|
ID: nht75-1.42OpenDATE: 07/14/75 FROM: AUTHOR UNAVAILABLE; J. C. Schultz; NHTSA TO: Hendrickson Mfg. Company TITLE: FMVSS INTERPRETATION TEXT: Please forgive the delay in responding to your letter of March 26, 1975, requesting an interpretation of the masking requirements of Federal Motor Vehicle Safety Standard No. 106-74, Brake Hoses. The requirement that the label on a brake hose remain visible after painting was amended on March 17, 1975, (40 FR 12088, Docket No. 1-5, Notice 16) to permit the label to remain masked if (1) the masking material is affixed in such a way that no adhesive contacts any part of the label and (2) the masking is manually removable. Since the requirement that the label be masked or visible, rather than obscured, is a vehicle requirement, it is not effective until September 1, 1975. Vehicles manufactured before that date may contain hose which has been painted over. |
|
ID: nht75-1.6OpenDATE: 02/11/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Insurance Institute for Highway Safety TITLE: FMVSS INTERPRETATION TEXT: Feb. 11, 1975 N40-30 Mr. A. B. Kelley Senior Vice President Insurance Institute for Highway Safety Suite 300 600 New Hampshire Avenue, N.W. Washington, D. C. 20037 Dear Ben: This is to confirm our understanding with respect to public meetings to be held on the subject of the Hydraulic Brake Standard, No. 105-75. If any significant changes are to be made in the standard, a notice of proposed rulemaking will be issued. Toward the end of the comment period on that NPRM, the agency will hold a public hearing concerning the contents of the proposal. At that time you will have the opportunity to present your views in full. Sincerely, Richard B. Dyson Assistant Chief Counsel |
|
ID: nht74-4.7OpenDATE: 06/14/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: The Berg Manufacturing Company TITLE: FMVSS INTERPRETATION TEXT: This responds to your December 21, 1973, letter and subsequent communication with Mr. Sidney Williams of the NHTSA Handling and Stability Division asking if a check valve located at the isolated reservoir (as pictured in your schematic drawing) to protect the trailer service reservoir(s) would comply with S5.2.1.5 of Standard No. 121, Air brake systems. The check valve may be placed at the isolated tank to protect the trailer service reservoir as specified in S5.2.1.5. It appears from your schematic that a single failure in the service brake system could cause loss of service brakes on both trailer axles. It should be noted that if this arrangement is used and a significant safety problem result, it would be subject to NHTSA safety defect authority. |
|
ID: nht91-6.24OpenDATE: October 16, 1991 FROM: D. E. Graham -- Engineering Manager, Regulatory, Test & Service Engineering, ASC Incorporated TO: Richard Reed -- Office of Crash Avoidance, NHTSA TITLE: None ATTACHMT: Attached to letter dated 11-20-91 from Paul Jackson Rice to D. E. Graham (A38; Std. 118) TEXT: I would like to request a formal written response to a question of interpretation of the recently revised FMVSS 118 - Power Operated Window Systems (Docket No. 87-10" Notice 4). Specifically, the sections in question for interpretation are S5(a) and S5 (b). The question is: Do these sections in any way apply to the rearward edge of a venting, sliding sunroof as it moves from the vent position to the fully closed position? Your timely response would be beneficial in ASC Incorporated's ongoing efforts to fully comply with the applicable safety standards for current and new products. |
|
ID: nht67-1.30OpenDATE: 02/27/67 FROM: AUTHOR UNAVAILABLE; William Haddon, Jr., M.D.; NHTSA TO: North America Seat Belt Council, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 16, 1967. Motor Vehicle Safety Standard No. 209 applies to seat belt assemblies manufactured after February 28, 1967, for use in passenger cars, multipurpose passenger vehicles, trucks, and buses. Since Motor Vehicle Safety Standard No. 208, which provides that a Type 1 or Type 2 seat belt assembly that conforms to Motor Vehicle Safety Standard No. 209 shall be installed in each passenger car seat position, has an effective date of January 1, 1968, until that date seat belt assemblies installed in passenger cars need not conform to Standard No. 209 unless the seat belt assemblies have been manufactured after February 28, 1967. Please do not hesitate to call upon us if we can be of further service to you. |
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.