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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



Displaying 8271 - 8280 of 16517
Interpretations Date

ID: nht88-3.45

Open

TYPE: INTERPRETATION-NHTSA

DATE: 09/12/88

FROM: NANCY F. MILLER -- US DEPARTMENT OF TRANSPORTATION

TO: BEVERLY B. BYRON -- U. S. HOUSE OF REPRESENTATIVES

TITLE: NONE

ATTACHMT: ATTACHED TO LETTER DATED 10/27/88 FROM ERIKA Z JONES TO BEVERLY B BYRON; REDBOOK A 32, STANDARD 205; LETTER DATED 08/25/88 FROM BEVERLY B BYRON T. NANCY MILLER; MEMORANDUM DATED 08/14/83 FROM C. RICHARD FRAVEL TO WHOM IT MAY CONCERN RE JOSEPH C IAMPA JR; MEMORANDUM DATED 08/04/88 FROM ARTHUR J. LOMART TO WHOM IT MAY CONCERN; LETTER DATED 08/01/88 FROM C.E. SHUE TO JOSEPH CIAMPA RE 0590630; LETTER DATED 08/24/88 FROM JOSEPH L. CIAMPA TO BEVERLY B. BYRON

TEXT: Dear Ms. Byron:

Thank you for your letter forwarding correspondence from your constitutent, Mr. Joseph L. Ciampa, Jr.

I have transmitted your inquiry to the appropriate Departmental officials who are familiar with this matter and they will respond to you directly.

I appreciate your contacting me and hope you will not hesitate to call if I can be of any further assistance.

ID: nht88-3.46

Open

TYPE: INTERPRETATION-NHTSA

DATE: 09/12/88

FROM: RUSSELL A. STORMS

TO: NAC EXECUTIVE DIRECTOR OFFICE OF TRAFFIC OPERATIONS FEDERAL HIGHWAY ADMINISTRATION

TITLE: NONE

ATTACHMT: ATTACHED TO LETTER DATED 08/17/89 FROM STEPHEN P. WOOD -- NHTSA TO RUSSELL STORMS; REDBOOK A34; STANDARD 125; VSA 108[B]; LETTER DATED 09/23/88 FROM HARRY B. SKINNER -- DOT TO RUSSELL A. STORMS

TEXT: Dear Sir or Madam:

We are writing pursuant to Section IA-6 of the Manual on Uniform Traffic Control Devices to obtain recognition for a new device designed to warn motorists of a hazardous situation.

We have a patent pending on a multiple-sided emergency traffic warning marker that is designed to be employed by a motorist immediately prior to the employment of flares or other warning devices. The marker is basically a tetrahedral configuration, cont oured and proportioned to ensure a warning display to oncoming vehicles when the marker is placed on a roadway surface (drawing attached).

The marker is basically of a "bean bag" nature that is foldable and stackable for easy transportation and storage in the vehicle when not in use and which is of relatively low cost so that a plurality of markers may be economically carried and deployed b y the vehicle driver. It is seven (7) inches in height and made of reflective material.

The primary advantage of this marker is that it can be employed quickly in the event of an emergency by a motorist and is not of an incendiary nature and can be safely stored in the passenger compartment of a vehicle. It is our opinion that this particu lar marker affords a measure of protection not available by other products currently available and would represent an improvement in traffic safety.

In closing, if we intend to bring this product to market, it is our understanding that your organization is the appropriate forum for approval of this product. Please advise us of a proper course of action necessary to gain this approval.

Thank you for your help.

Sincerely,

[DRAWING OMITTED]

ID: nht88-3.47

Open

TYPE: INTERPRETATION-NHTSA

DATE: SEPTEMBER 12, 1988

FROM: ERIKA Z. JONES -- CHIEF COUNSEL, NHTSA

TO: M. IWASE -- MGR., TECHNICAL ADMINISTRATION DEPT., KOITO MFG. CO., LTD. TITLE: NONE

ATTACHMT: ATTACHED TO LETTER DATED 4-9-90 TO M. IWASE FROM STEPHEN P. WOOD; (A35; STD. 108). ALSO ATTACHED TO LETTER DATED 10-18-89 TO ERIKA Z. JONES FROM M. IWASE AND LETTER DATED 4-8-88 TO ERIKA Z. JONES FROM M. IWASE. TEXT:

This is in reply to your letter of April 8, 1988, with respect to the agency's proposed S7.7.5.2 of Standard No. 108, on-vehicle aiming requirements which would include a Vehicle Headlamp Aiming Device (VHAD). This was proposed on December 29, 1987, as Notice 5 to Docket 85-15.

You have asked whether two designs contemplated by Koito comply with the VHAD as proposed. With respect to the second design, "Structure-2", you requested that it be considered confidential as it involves a Koito idea related to a patent application. However, you withdrew that request on June 9, 1988.

With respect to your two designs, you appear to have understood that the agency's intent in the proposal was to provide broad parameters for VHADs to afford manufacturers design freedom in meeting the specifications. Under S7.7.5.2 it is the headlamp system that "includes" a VHAD, rather than "incorporates' it. Under subsection (b)(7) photometric testing is provided for "The VHAD and headlamp assembly (if the headlamp is separable or intended to be used with the VHAD)...." This means that the VHAD may be integral with the headlamp assembly, or separate from it (though presumably provided with the vehicle as part of its original equipment), as fits the manufacturer's design. Each of your designs complies with the intent of S7.7.5.2; however, I must emphasize that this is only a proposal, and the form of a final requirement, if any, has not been determined.

We have further comments about your devices. Structure 1 incorporates a stationary lens and housing, but the reflector is adjustable. The lamp must be designed to conform to the photometric requirements of Standard No. 108 with the reflector in any position within the proposed aimability range of +/- 4 degrees vertical and +/- 2 1/2 degrees horizontal, or any combination thereof. Structure 2 features a detachable spirit level which is inserted when the replaceable bulb is removed from the headlamp. Although the proposal does not specifically prohibit this feature, the test procedures do not anticipate a VHAD design where the light source would be removed and replaced with the VHAD.

I hope that this answers your question.

ID: nht88-3.48

Open

TYPE: INTERPRETATION-NHTSA

DATE: 09/13/88 EST

FROM: ERIKA Z. JONES -- CHIEF COUNSEL, NHTSA

TO: ROBERT W. STUCHELL

TITLE: NONE

ATTACHMT: LETTER DATED 4-30-88, TO MR. VINSON FROM, ROBERT W. STUCHELL, OCC-1973

TEXT: This is in reply to your letter of April 30, 1988, to Mr. Vinson of this Office as to the existence of Federal or State regulations "governing sale and/or use of lighted signs of any shape placed on the inside of the rear window of aftermarket cars. Suc h signs would not be connected with any new car purchase."

The Department of Transportation has no restriction on the sale of signs for use inside motor vehicles. Nor are there any Federal regulations that would prevent an owner from installing or using such signs. However, if the sign were of such a nature th at it is intended to be installed by a dealer or motor vehicle repair business, the installer must insure that its installation does not render inoperative in whole or in part any device installed on the vehicle pursuant to a safety standard. For exampl e, if the sign is installed on a passenger car equipped with a center highmounted stop lamp, the sign must not block the light from the lamp, or operate in a manner so as to cause confusion with it. Its installation must not affect the wiring of the oth er lighting equipment. Other safety problems such a sign might create are a partial blockage of view through a rear view mirror, or the creation of light on the rear window, resulting in glare in the rear view mirror.

We are not in a position to advise you as to the acceptability of the device under State law. You may wish to consult the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203 for advice.

ID: nht88-3.49

Open

TYPE: INTERPRETATION-NHTSA

DATE: 09/13/88

FROM: GLENDA SWANSON LYLE -- DIRECTOR REGIONAL TRANSPORTATION DENVER COLORADO; JACK MCCROSKEY -- DIRECTOR REGIONAL TRANSPORTATION DISTRICT D DENVER COLORADO

TO: LARRY COOK -- SAFETY STANDARDS ENGINEER NHTSA

TITLE: NONE

ATTACHMT: ATTACHED TO LETTER DATED 12/09/88 TO JACK MCCROSKEY AND GLENDA SWANSON LYLE FROM ERIKA Z. JONES REDBOOK A33, STANDARD 119; LETTER DATED 08/26/88 TO MARVIN ORNES FROM R.E. MORGAN; LETTER DATED 09/09/87 TO R ROGERS FROM R.E. MORGAN, RE GOODYEAR M ILEAGE TIRES

TEXT: Dear Mr. Cook:

Thanks so much for talking with me this morning. The issue, as I'm sure you will recall, concerns the disparity between the "labeling" and the "use" of tires the Goodyear Corporation leases to Denver's Regional Transportation District for use on its fle et of approximately 750 transit buses.

By way of brief background, let me say that the RTD is an independent unit of local government, established by the Colorado General Assembly, and governed by a fifteen-person Board of Directors. The Directors, who are elected by the voters of the distri ct for four-year terms, have full legal responsibility for operating the District. The Directors hire a General Manager who is given day-to-day authority and who reports to the Board. I'm enclosing a small booklet giving some of the District's operatin g statistics for 1987.

The District provides three types of service:

1. Local. These buses operate primarily in areas where the speed limit is 35 miles per hour. However, these buses do operate for short portions of their routes where the limits range from 40 to 45 and even up to 55 miles per hour.

2. Express. These buses operate mainly--70% to 80% of the time--on local freeways where the speed limits are 55 miles per hour. Some small portion of their routes may be in 65 mile per hour limits.

3. Regional. These operate primarily in freeways where the limits run from 55 to 65 miles per hour.

2

My most pressing question for now concerns the Express buses. The tires Goodyear furnishes RTD for Local and Express use are called DXT and XT tires. The DXT tires have a maximum speed of 35 miles per hour marked on them; the XT tires have a maximum spe ed of 55 miles per hour on them.

RTD is currently using the DXT (35 miles) and the XT (55 miles) almost interchangably on the Express buses. (That is, RTD is using tires marked maximum speed 35 miles on routes where much, probably most, of the travel is at 55 miles per hour).

I am enclosing one memo and one letter, both of which are purportedly from Goodyear, saying that this practice may be acceptable. Please note that neither document is on Goodyear stationery and that neither document has the full signature of the author, or gives the author's official position in the company.

Some of us here at RTD are very much worried about the use of tires contrary to their labeling on buses carrying 40 to 70 passengers. We are also concerned by RTD's liability should an accident owing to tire failure occur.

Could you please, at your earliest possible convenience, let us know your view of the possible safety hazards and our possible legal liabilities. We would also like, should you be in a position to give it, your advice on what we should do. Should we co ntinue to use the tires contrary to their labeling? Or should we act to bring usage in conformity to labeling.

We look forward to your reply. We think quick action is essential.

Cordially,

ENCLOSURES

(Regional Transportation District Report omitted.)

ID: nht88-3.5

Open

TYPE: INTERPRETATION-NHTSA

DATE: 08/15/88

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: LOUIS F. KLUSMEYER -- SENIOR RESEARCH SCIENTIST VEHICLE RESEARCH AND DEVELOPMENT, SOUTHWEST RESEARCH INSTITUTE

TITLE: NONE

ATTACHMT: LETTER DATED 07/11/88 TO TAYLOR VINSON FROM LOUIS F KLUSMEYER, OCC - 2275; Std. 108

TEXT: Dear Mr. Klusmeyer:

This is in reply to your letter of July 11, 1988, to Mr. Vinson of this office with reference to a "deceleration" or "pre-braking" concept.

As you presently envision the implementation of this concept, an amber lamp would be activated when the driver's foot is removed from the accelerator pedal, and would be extinguished automatically when the driver reapplies pressure to the accelerator ped al. You believe that the optimum location appears to be immediately adjacent to the center highmounted stoplamp. You believe further that this location has already been considered by NHTSA for this purpose, and ask whether it is precluded by Standard N o. 108.

Your belief is based upon the Federal Register notice of October 1983 adopting the center highmounted stoplamp, which stated that "Other types of lamps or added functions such as deceleration signals may be desirable and should be investigated." However, this was in the context of alternatives to adoption of the center lamp, and relates to the agency's statement in the same paragraph that "with additional research, more nearly optimum specifications for stoplamp configurations may be developed." Indeed, the agency made it quite clear in prohibiting combining the center lamp with any other lamp or reflector (paragraph S4.4) that no added functions were contemplated or desirable.

Under paragraph S4.4 therefore, a deceleration lamp and the center stop lamp could not be combined. S4.4 would not prohibit an amber lamp adjacent to the center lamp. However, paragraph S4.1.3 prohibits optional lighting equipment if it would impair th e effectiveness of lighting equipment required by Standard No. 108. Your letter indicates that the deceleration signal is deactivated by renewed pressure on the accelerator pedal (and not by pressure on the brake pedal) so that a following driver would be presented with both amber and red signals, creating the possibility of confusion, and hence impairment. You have not indicated whether the deceleration lamp would be steady-burning or

2 flashing, but we believe the possibility of confusion would increase were the lamp flashing. However, were the lamp to be extinguished when the brake pedal is applied (which activates the stop lamps), then the possibility of confusion would be substan tially lessened. With respect to deceleration warning systems, last year the Flxible Corporation determined that a system installed on its buses created an impairment, and hence a noncompliance with paragraph S4.1.3. The company then conducted a notific ation and remedy campaign (87V-089) as required by statute. The company concluded that its flashing amber deceleration lamps could create confusion when activated simultaneously with the red steady burning stoplamps.

I hope that this answers your question.

Sincerely,

ID: nht88-3.50

Open

TYPE: INTERPRETATION-NHTSA

DATE: SEPTEMBER 14, 1988

FROM: RICHARD W. WARD -- VICE PRESIDENT; K-D LAMP COMPANY

TO: ERIKA Z. JONES -- NHTSA

ATTACHMT: LETTER DATED NOV. 3, 1988 TO RICHARD W. WARD, V. P., K-D LAMP CO., FROM ERIKA Z. JONES, CHIEF COUNSEL, NHTSA

TEXT: This is in reference to your letter of Aug. 19, 1988 to Paul Scully regarding the exclusion of reflex reflector area when calculating minimum square inch lens area. Apparently your letter has caused a future customer of KD Lamp Co. to reconsider and rej ect the use of a Turn Signal Lamp of ours which has a lens area of 8 square inches. The following information and enclosed documentation is offered for your evaluation, and I respectfully request your reply to clarify the requirement of minimum square i nch lens area for Turn Signal and Stop Lamps.

In S1. of Purpose & scope FMVSS 108 the standard covers requirements for original and replacement lamps. When a new lamp is designed the requirements of 108 in effect at that time are naturally incorporated into the design. The present requirements of 108 shown in Table #1 for vehicles 80 or more inches wide indicates the applicable SAE standard is J-588e Sept. 1970 for Turn Signal Lamps and J-586c Aug. 1970 for Stop Lamps. Both of these SAE standards in section 3.2 require a minimum lens area of 8 s quare inches (rear lamps) for a single compartment lamp. The device in question meet the J-588e and J-586c, however, our customer has interpreted your letter that 12 square inch minimum lens area is the requirement. Their conclusion is based on the 2nd paragraph of your letter wherein you make reference to S4.1.1.7 of FMVSS 108 and 12 square inch lens area.

It is our position that S4.1.1.7 and S4.1.1.6 of FMVSS 108 is not the present requirements but rather an exception or a permissable use of an old SAE J-588d June 1966 and J-586b June 1966 for lamps used on vehicles manufactured between 1973 and 1978 (ref . page 28238 Fed. Reg. Aug. 6, 1986). If the full context of S4.1.1.7 and S4.1.1.6 is taken into consideration it is apparent the intent, particularly the words "may also be designed", of these sections is to cover vehicles of older manufacture.

After your review of the above and attachments, I would appreciate your comments so the immediate problem as well as any future questions in this regard can be resolved.

Thank You.

ID: nht88-3.51

Open

TYPE: INTERPRETATION-NHTSA

DATE: SEPTEMBER 14, 1988

FROM: AL CUNNINGHAM -- CHIEF ENGINEER WESTBAR CORPORATION

TO: ERIKA JONES -- CHIEF COUNSEL D.O.T.

TITLE: INTERPRETATION OF SAE DEFINITIONS AS THEY APPLY TO FMVSS 108

ATTACHMT: LETTER DATED NOV. 3, 1988 TO AL CUNNINGHAM, CHIEF ENGINEER, WESTBAR CORPORATION, FROM ERIKA Z. JONES, CHIEF COUNSEL, NHTSA

TEXT: We are writing your office requesting official clarification of definitions referred to in SAE J588e as it applies to FMVSS 108. The definition in question is, 2.2 "Multiple Compartment Lamp" and the term used in 3.1 "Single Compartment Lamp".

With this request, we are furnishing two lamps as examples, one identified as 3504 exp. and the second as 3504. The first sample (3504 exp.) has a housing with back and four sides containing a two filament bulb with a single lens covering face of hou sing. This lamp photometrically complies to the basic requirements of a class "A" tail, stop and turn lamp. Would the sample submitted as described above be defined as a single compartment lamp?

The second sample has a housing with a back, two sides and one end, containing one #57 bulb and one #1157 (2 filament) bulb. This housing is closed with two red lenses, one on the end and one on the face with an additional clear lens on bottom side. This lamp also complies to all standards of a class "A" tail, stop and turn lamp plus side marker clearance, license plate illuminator and class "A" reflex side and rear. Would the sample, as submitted and described, be defined as single compartment la mp?

Thank you for reviewing our requests. We look forward to receiving your interpretation of these definitions as they apply to our questions and samples furnished.

Enclosures - 2 samples

ID: nht88-3.52

Open

TYPE: INTERPRETATION-NHTSA

DATE: 09/14/88

FROM: WENDELL D. KEGG -- TIRE WHEEL CONSULTANTS

TO: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TITLE: NONE

ATTACHMT: ATTACHED TO LETTER DATED 01/1/8/89 FROM ERIKA Z. JONES -- NHTSA TO WENDELL D. KEGG, REDBOOK A33, STANDARD 109

TEXT: Dear Ms. Jones:

I am confused by the FMVSS 110 Standard. As I read Paragraph S4.3.1 covering inflation pressure on the vehicle placard, the tire cannot by inflated beyond that maximum pressure embossed on the tire. Subparagraph S4.3.1(c) is not clear.

Can a vehicle manufacturer specify a higher inflation pressure in a spare tire application than that which is embossed on the sidewall of the tire?

Thank you.

Very truly yours,

ID: nht88-3.53

Open

TYPE: INTERPRETATION-NHTSA

DATE: 09/15/88

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: M. IWASE -- MANAGER TECHNICAL ADMINISTRATIVE DEPARTMENT KOITO MFG. CO., LTD.

TITLE: NONE

ATTACHMT: LETTER DATED 07/30/80 TO DIETMAR M HAENCHEN FROM FRANK BERNDT; LETTER DATED 02/22/88 TO ERIKA Z JONES FROM M IWASE RE INSTALLATION OF TAIL AND STOP LAMP ONTO MOVING VEHICLE PART

TEXT: Dear Mr. Iwase:

This is in reply to your letter of February 22, 1988, asking whether location of a stop and taillamp on a deck lid would comply with Federal Motor Vehicle Safety Standard No. 108. In your opinion this is acceptable because the vehicle complies with the trunk lid closed. You have also asked, alternatively, whether the deck lid is an acceptable location for turn signal lamps.

Section S4.3.1 of Standard No. 108 requires lighting devices to be mounted on "a rigid part of the vehicle...that is not designed to be removed except for repair". In past interpretations the agency has stated that a deck lid is "a rigid part of the veh icle", and that compliance with the standard will be determined with the deck lid closed. Thus, it may be used for mounting lamps and reflectors required by Standard No. 108. However, Table IV specifies the location for rear lamps. Stoplamps, taillamp s, rear turn signal lamps, and rear reflex reflectors must be mounted "as far apart as practicable". Although the determination of practicability is initially made by the vehicle manufacturer, the agency in its enforcement efforts would consider whether lighting equipment mounted on the deck lid meets the requirements of Table IV. On the other hand, the separation requirement is not specified for backup lamps and license plate lamps.

I have enclosed for your information a copy of a 1980 interpretation that addressed a similar question. As you will note, the agency raised some safety concerns in that letter which could also pertain to your design.

Operation of a motor vehicle in the United States is subject to the laws of the individual States, some of which may prohibit operation of a vehicle when its turn signals and stop lamps are not visible.

In summary, we urge you to consider the issues described above, including those raised in the 1980 letter, in deciding whether to proceed with this design.

ENCLOSURE

Sincerely,

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.

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