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: nht72-3.9OpenDATE: 09/01/72 FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA TO: Rolls-Royce, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 19, 1971, concerning the placement of vanity mirrors in sun visors. We apologize for our delay in responding to your letter. The issues it raised, however, are of consequence to manufacturers other than Rolls-Royce, and concerned basic matters of interpretation of Standard No. 201 which have only recently been resolved. The National Highway Traffic Safety Administration has determined that paragraph S3.4.1 of Standard No. 201 does not prohibit the installation by manufacturers of vanity mirrors on sun visors. Consequently, manufacturers are free to incorporate such mirrors into or onto sun visors, including mirrors that are recessed into the surface of the visor as in the sample you enclosed. SINCERELY, ROLLS-ROYCE, INC. May 19, 1971 National Highway Traffic Safety Administration U.S. Department of Transportation attention: Ref. FMVSS 201 Mr. Risteen Gentlemen: F.M.V.S.S. 201 OCCUPANT PROTECTION, INTERIOR IMPACT -- SUNVISOR, VANITY MIRRORS The mirror was deleted from visors at the introduction of the Safety Standard. Customer criticism of the deletion of the mirror, however, has prompted us to seek the following interpretation, if in fact they would be regarded as acceptable: We are aware that a Notice of Proposed Rule Making to Amend F.M.V.S.S. 205 - Docket 71-1; Notice 1 - glazing materials exist, where mirrors should meet the requirements of items 1 to 13 of ANS-Z26. With (Illegible Word) proposed effective date of January, 1972, however, it is hoped we will have material for the mirrors, but we are still not certain that it would qualify as energy absorbing. The method of fitting mirrors to sunvisors to markets other than North America is: 1. 4-DOOR VEHICLES A plain glass mirror, backed with adhesive tape, so that should it fracture fragments adhere to the tape. The glass plus the tape is in a recess in the foam which makes up the body of the visor. A thin gauge soft aluminum frame is used to tidy up the leather cover around the aperature. 2. 2-DOOR VEHICLES A semi-rigid plastic mirror is used in a shallow recess in the foam. Again a frame is used to tidy up the trim around the aperature. In other respects the construction is the same. In order to help in your interpretation, a sunvisor with the glass mirror and a sample of the plastic mirror is enclosed. If necessary, you may strip them down and break them if it will assist in arriving at a decision. May we request an early response. Trevor Williams Service Manager |
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ID: nht72-4.1OpenDATE: 08/31/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: General Motors Technical Center TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 21, 1972, on the subject of the operation of the seat belt warning system when the vehicle is in one of the free start modes allowed by S7.4.3 and S7.4.4 of Standard No. 208. You are correct in your understanding that S7.3.5.4 does not require the warning to operate when the ignition switch is in the "start" position if the conditions described in S7.4.3 and S7.4.4 exist. Under those conditions, the interlock system continues to act as if the operation of the belt systems had not been followed by their release. By the same logic, the warning system activation required by S7.3.5.4 is in abeyance until the ending of the free start conditions. |
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ID: nht72-4.10OpenDATE: 11/09/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Renault, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 16, 1972, concerning the seat adjustment procedures of S8.1.2 of Motor Vehicle Safety Standard No. 208. As described in your letter, some models manufactured by Renault have front seats that can be adjusted to an extreme forward position to allow the reclining seat back to be fully lowered. You imply that this position cannot be used for driving the vehicle, and ask whether the "forwardmost" position referred to in S8.1.2 could be interpreted to be the forwardmost driving position. The purpose of S8.1.2 is to specify an adjustment position that is appropriate for the 50th percentile adult male occupant used in the standard's barrier tests. If the adjustment range is determined by using the extreme forward position you describe, the midway point would no longer be appropriate for the 50th percentile adult male size. It is therefore consistent with the purpose of S8.1.2 to exclude the extreme, non-driving positions in determining the midway adjustment position. However, despite the references in some parts of the standard to an occupant of the 5th percentile adult female size, the adjustment range specified in S8.1.2 does not refer to this or any other size of occupant and we are of the opinion that no occupant size specification can be read into the section. We would consider a position to be outside the range used to determine the midway point of S8.1.2 if it cannot reasonably be used for driving and if it is separated from other positions by a distance greater than the normal distance between positions. It would appear that the position described in your letter meets these criteria and that it should therefore be excluded in determining the midway position under S8.1.2. |
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ID: nht72-4.11OpenDATE: 06/02/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 9, 1972, in which you again raise the problem of where to place the seat in tests for which Standard 208 specifies that the seat is to be at the midway position but the seat track has no adjustment position that coincides with the midway point. Our reply of March 2, 1972, stated that when the midway point is exactly halfway between two adjustment notches, the seat should be placed in the rear notch. You are correct in pointing out that if the notches were on the upper seat rail the seat would be moved forward if these instructions were followed. It was our intent to specify rearward seat movement in each case in which the midway point on the track fell exactly between two notches. In Case (2) of your letter, therefore, it will be our practise to move the seat rearward from the position shown in red until the next notch is reached. |
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ID: nht72-4.12OpenDATE: 03/02/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 11, 1972, in which you requested our interpretation as to how seats with varying numbers of adjustment positions are to be adjusted to the position "midway between the forwardmost and rear most position," as specified in S8.1.2 of Standard 208. The intent of the "midway" provision in S8.1.2 is that the seat must be placed as nearly as possible at the midpoint of its fore and aft travel. Since the standard also provides that the seat is in an adjustment position -- a notch -- there is a possibility that there will not be a notch at the exact center of the range. In such cases, the seat is placed in the notch nearest the midpoint of the seat's travel. In your case A, if the notches are evenly spaced, the middle notch would probably be the nearest to the midpoint and would therefore be used. In your case B, if the two middle notches are not equidistant from the midpoint, the nearest notch would be used. If they are equidistant, the rearmost notch would be used. It is not necessary to make a special notch. |
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ID: nht72-4.13OpenDATE: 02/03/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Toyota Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This letter is in response to your inquiry of January 6, 1972, regarding the relationship of Standards No. 208 and No. 216. You interpret Standard 216, paragraph S3. Application, which states that the Standard does not apply to passenger cars "that conform to the rollover test requirements (S5.3) of Standard 208 by means that require no action by vehicle occupants," as follows: 1. From August 15, 1973, the effective date of Standard 216, to August 15, 1977, passenger cars are not required to meet Standard 216 if they conform to the "first option" of Standard 208. 2. For the period of August 15, 1973, through August 14, 1975, passenger cars which are designed to conform to the "second" or proposed "third" option of Standard 208 are not required to meet Standard 216 if they meet the rollover requirements (S5.3) by passive means (when tested under the applicable conditions of S8), even though in Standard 208 the rollover requirement is specified only for "option 1." These interpretations are correct. Please write if we can be of further assistance. |
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ID: nht72-4.14OpenDATE: 09/08/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 22, 1972, regarding the applicability of the requirements of S5 and S6 of Motor Vehicle Safety Standard No. 208 to trucks and multipurpose passenger vehicles conforming to S4.3.2 and to buses conforming to S4.4.2 of the standard. Although sections S6.2 and S6.3 have been amended to refer to belt systems, the reference applies only to vehicles that are required by S4 to meet the injury criteria by use of seat belts. Vehicles manufactured under the options of S4.3.2 and S4.4.2 are not required by the terms of those sections to meet either the occupant crash protection requirements of S5 or the injury criteria of S6. Such vehicles are therefore not affected by the amendments to S6.2 and S6.3, and continue to be exempt from compliance with S5 and S6. |
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ID: nht72-4.15OpenDATE: 07/05/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co. Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 20, 1972, on the subject of the options which may be included in the unloaded vehicle weight of a passenger car under S8.1.1 of Standard 208. The definition of "unloaded vehicle weight" is intended to include a vehicle equipped with any combination of optional items that are installed by the factory or by the dealer with the factory's authorization. The weight of equipment installed by the dealer without authorization by the manufacturer would not be includable. To answer your question by use of your example, you must concern yourself with both factory optional air conditioning and with dealer optional air conditioning that is authorized by the factory. |
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ID: nht72-4.16OpenDATE: 10/27/72 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 18, 1972, on the subject of warning system and interlock system operation under Standard No. 208. The table enclosed with your letter lists all combinations of front seat occupancy and front seat belt usage that are possible in a vehicle with two front seating positions. You ask, as to each of these combinations, whether you have correctly understood the operation of the interlock and warning system. We find that a large majority of the combinations shown in your table are correctly interpreted but that a few are in error or are in need of further clarification. The primary source of error in the table seems to be confusion as to the effect of the driver's absence from his seat. Under S7.4.1, the conditions under which a failure to operate the belt will require the interlock system to prevent engine operation are specified in S7.4.1(a) and (b). Each of these conditions specifies that the driver's position is occupied, so that if the driver is not in his seat neither condition (a) nor condition (b) is met and interlock system operation is not required. Applying this interpretation to the matrix in your table discloses that two cases, 18 and 25, are incorrectly interpreted. In each of these cases the driver is not in his seat and the interlock would not be required to operate, even though in both cases the passenger has operated his belt out of sequence and in one case the belt at the vacant driver's position is buckled. Although interlock operation is not required in cases 18 and 25, a manufacturer would be permitted to design his interlock system to operate in these circumstances. Eighteen and 25 should therefore be treated in the same manner as the other cases in the matrix (11-17, 24) in which interlock operation is shown to be within the manufacturer's discretion. The warning system, which is required to operate when the ignition is in the start position if the operations required by S7.4.1 to start the engine have not been performed, is on a different footing under conditions where the interlock is permitted, but not required, to operate. Under such conditions, S7.3.5.4 does not require the warning to operate in the start position. We would, however, strongly recommend that the warning system be designed to operate whenever the interlock prevents engine operation, regardless of whether or not S7.4.1 requires operation. One other case in your table should also be corrected. Under Case 4, you indicate that interlock operation would be within the discretion of the manufacturer. It is our opinion that if the driver has properly operated his belt the interlock and warning system should not operate, even though the belt at the empty passenger's seat has been fastened. Please advise us if you have further questions. |
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ID: nht72-4.17OpenDATE: 02/01/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Borg-Warner Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your request of January 18, 1972, for a letter confirming the written interpretation of Standard 209 concerning automatic locking retractors given to Toyota on November 10, 1971. We understand from your letter that the "Borg-Warner Maji-Buckle" is identical to the combination buckle and retractor shown us by Toyota. A seat belt with the Maji-Buckle" is, therefore, considered to be equipped with an automatic locking retractor. A retractor is classified according to its operation, not its design, and the "Maji-Buckle" operates in the manner prescribed by Standard 209 for automatic locking retractors. The comments made to Toyota concerning the test required by S5.3(a)(6) also apply to the "Maji-Buckle." Please advise us if we can be of further assistance. |
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.