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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 671 - 680 of 2066
Interpretations Date
 search results table

ID: nht94-9.8

Open

TYPE: Interpretation-NHTSA

DATE: January 8, 1994

FROM: Bob Carver -- Product Engineering, Wayne Wheeled Vehicles

TO: John Womack

TITLE: None

ATTACHMT: Attached to letter dated 3/24/94 from John Womack to Bob Carver (A42; Std. 217)

TEXT:

I have two matters in which I need rulings from the Chief Counsel regarding FMVSS 217. I've discussed both with Charles Hott and he recommended that I write you for an official response.

QUESTION 1:

There's some confusion here in our engineering department regarding the interpretation of the "Daylight Opening" and "Unobstructed Opening" as it applies to the new side emergency door specifications in FMVSS 217. Page 2 shows the allowable obstruction and the context in which "Daylight Opening" and "Unobstructed Opening" are used. Page 3 shows some measurements of our seats placed according to the "30 cm minimum" shown on page 2. Page 4 shows four different interpretations of the "Unobstructed Opening" area. Depending on the interpretation, between 9 and 15 people may be accommodated by a side emergency door. My question is this: of the four possibilities shown, which definition of the "Unobstructed Opening" area is correct? Mr. Hott indicated definition 4.

QUESTION 2:

Here is an excerpt from FMVSS 217 S5.5.3(a): "Each school bus ....shall have the designation "Emergency Door" or "Emergency Exit" as appropriate,.... For emergency exit doors, the designation shall be located at the top of, or directly above, the emergency exit door on both the inside and outside surfaces of the bus..... For emergency window exits, the designation shall be located at the top of, or directly above, or at the bottom of the emergency window exit on both the inside and outside surfaces of the bus."

I've seen a two-sided sticker used by other bus manufacturers. It is applied on the inside surface of a window and the same image "Emergency Door" or "Emergency Exit" can be read from both inside and outside the bus. Is it permissible for us to use this sort of decal, assuming it meets all other (i.e. FMVSS 302)?

I can make an educated guess on both questions, but I'd like an official ruling. I look forward to your response.

ATTACHMENT

Figure 5C - Mimimum Side Emergency Exit Clearance Specifications and Side Door Opening With Seat Obstruction. (Text and graphics omitted.)

ID: nht95-6.53

Open

TYPE: INTERPRETATION-NHTSA

DATE: September 20, 1995

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Dennis G. Moore -- President, Sierra Products, Inc.

TITLE: NONE

ATTACHMT: ATTACHED TO 7/31/95 LETTER FROM DENNIS G. MOORE TO NHTSA CHIEF COUNCIL

TEXT: Dear Mr. Moore:

This responds to your letter of July 31, 1995, with respect to lens area requirements of amber turn signal lenses.

You believe that "by reducing the minimal area of the Amber Turn Signal light lens from 12 square inches to approximately 8 square inches or 6 square inches the U.S. would have more practical rules for U.S. Exports at no expense to Safety. You ask that, "If NHTSA's Legal Council feels this error should be corrected through the Petitioning Process, I ask that this writing be considered a 'Petition for Change of FMVSS # 108 Request'".

Standard No. 108 contains two relevant regulations, one applicable to vehicles whose overall width is less than 80 inches, and one to those whose overall width is 80 inches or more.

Under paragraph S5.1.1.26(a), the functional lighted lens area of a single turn signal lamp of either red or amber on a vehicle whose overall width is less than 80 inches shall be not less than 50 square centimeters. This is approximately 8 square inches. Therefore, no rulemaking is required to implement your recommendation.

The standard that applies to turn signal lamps on vehicles whose overall width is 80 inches or more is SAE Standard J1395 APR85, incorporated by reference in Standard No. 108. Under its paragraph 5.3.2, the functional lighted lens area of a single turn signal lamp shall be at least 75 square centimeters, or approximately 12 square inches. Therefore, rulemaking is required to implement your recommendation.

We are transmitting your letter to our Office of Safety Performance Standards for consideration as a petition for rulemaking to change the minimum lens area requirement for turn signal lamps on large vehicles from 75 to 50 square centimeters. On September 4, 1995, I determined that your letter met our procedural requirements for a petition. Accordingly, the Office of Safety Performance Standards will inform you not later than January 1, 1996, whether your petition has been granted.

If you have any questions, you may refer them to Taylor Vinson of this Office (202-366-5263).

ID: nht95-4.31

Open

TYPE: INTERPRETATION-NHTSA

DATE: September 20, 1995

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Dennis G. Moore -- President, Sierra Products, Inc.

TITLE: NONE

ATTACHMT: ATTACHED TO 7/31/95 LETTER FROM DENNIS G. MOORE TO NHTSA CHIEF COUNCIL

TEXT: Dear Mr. Moore:

This responds to your letter of July 31, 1995, with respect to lens area requirements of amber turn signal lenses.

You believe that "by reducing the minimal area of the Amber Turn Signal light lens from 12 square inches to approximately 8 square inches or 6 square inches the U.S. would have more practical rules for U.S. Exports at no expense to Safety. You ask that, "If NHTSA's Legal Council feels this error should be corrected through the Petitioning Process, I ask that this writing be considered a 'Petition for Change of FMVSS # 108 Request'".

Standard No. 108 contains two relevant regulations, one applicable to vehicles whose overall width is less than 80 inches, and one to those whose overall width is 80 inches or more.

Under paragraph S5.1.1.26(a), the functional lighted lens area of a single turn signal lamp of either red or amber on a vehicle whose overall width is less than 80 inches shall be not less than 50 square centimeters. This is approximately 8 square inche s. Therefore, no rulemaking is required to implement your recommendation.

The standard that applies to turn signal lamps on vehicles whose overall width is 80 inches or more is SAE Standard J1395 APR85, incorporated by reference in Standard No. 108. Under its paragraph 5.3.2, the functional lighted lens area of a single turn signal lamp shall be at least 75 square centimeters, or approximately 12 square inches. Therefore, rulemaking is required to implement your recommendation.

We are transmitting your letter to our Office of Safety Performance Standards for consideration as a petition for rulemaking to change the minimum lens area requirement for turn signal lamps on large vehicles from 75 to 50 square centimeters. On Septemb er 4, 1995, I determined that your letter met our procedural requirements for a petition. Accordingly, the Office of Safety Performance Standards will inform you not later than January 1, 1996, whether your petition has been granted.

If you have any questions, you may refer them to Taylor Vinson of this Office (202-366-5263).

ID: nht90-2.15

Open

TYPE: INTERPRETATION-NHTSA

DATE: 04/12/90

FROM: BARRY FELRICE ASSOCIATE ADMINISTRATOR FOR RULEMAKING

TO: STEPHEN P. WOOD -- ACTING CHIEF COUNSEL NHTSA

TITLE: ACTION: PORSCHE'S MODIFIED ANTITHEFT EXEMPTION

ATTACHMT: ATTACHED TO LETTER DATED 05/31/90 FROM BARRY FELRICE -- NHTSA TO MIKE LOVE -- PORSCHE, A 35 PART 543; LETTER DATED 03/30/90 FROM MIKE LOVE -- PORSCHE TO JERRY CURRY -- NHTSA ADMINISTRATOR ON 49 CFR PART 543 EXEMPTION

TEXT: On April 4, 1990, Porsche Cars North America, Inc. (Porsche) submitted a request for approval of a modification to the existing antitheft device for the exempted MY 1990 Porsche 911 and 928 carlines.

Rulemaking has reviewed the changes submitted by Porsche, and finds that the system activation process as described by Porsche would not undermine the device and that it would qualify for de minimis treatment. Porsche has changed the antitheft system by allowing it to additionally monitor the glove box for opening. This means that if the glove box is opened while the system is armed, the alarm will be activated. Previously, the antitheft system would only monitor the vehicle's doors, hood, hatc, igni tion switch, and removal of its radio.

The system's alarm control unit will now be integrated with the central locking and interior light control units to save space and to simplify the vehicle's electrical system. Porsche's antitheft system will also now have the capability to accept other inputs such as motion sensors, and improved diagnostic capability to enhance serviceability.

The new system will continue to be armed by locking either the driver or passenger door with the ignition key. The same points of entry will continue to be monitored by the system and the disabling and alarm features will remain the same. The new syste m will also continue to be as protected and tamper resistant as the current system.

As stated above, Rulemaking does not believe that these changes are significant enough to warrant submission of a full modification petition by Porsche and, therefore, would qualify for de minimis treatment. Accordingly, Rulemaking requests a letter gra nting the change to the antitheft system be forwarded to Porsche, pursuant to Part 543.9(j).

Attachment Letter from Porsche Cars North America, Inc.

ID: aiam3547

Open
Mr. G. K. Blair, Sales Manager, Norton Motors (1978) Limited, Lynn Lane, Shenstone, Lichfield, Staffordshire WS14OEA, England; Mr. G. K. Blair
Sales Manager
Norton Motors (1978) Limited
Lynn Lane
Shenstone
Lichfield
Staffordshire WS14OEA
England;

Dear Mr. Blair: This is in reply to your letter of March 5, 1982, asking whether proposed motorcycle taillamp assembly would comply with Motor Vehicle Safety Standard No. 108.; As you point out, the standard requires a minimum distance of 4 inche edge to edge between turn signal lamps and stop/tail lamps. Since you state that you cannot achieve this with your design, the lamp as currently designed would not be permitted by our standard. This will confirm the oral interpretation provided by Taylor Vinson of this office when you telephoned on March 22.; You will be interested to know that we are presently studying side an rear conspicuity of motorcycles. This research is being conducted by Ketron in Philadelphia, Pennsylvania, and the final report is expected in July 1982 should you wish to obtain a copy of it from us.; As you requested confidential treatment of your engineering drawing, w are returning it to you.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam3678

Open
Mr. T. J. Brown, Mohawk Rubber Company, Roanoke, VA 24017; Mr. T. J. Brown
Mohawk Rubber Company
Roanoke
VA 24017;

Dear Mr. Brown: This is in response to your March 28, 1983, letter to Roger Fairchil of this office, requesting confirmation of your understanding of the effective dates for the recent suspension of treadwear grading under this agency's Uniform Tire Quality Grading Standards.; Your understanding of the effective dates is correct. Tires produced i molds manufactured on or after August 8, 1983, must have the new grading format which excludes treadwear information. Tires produced in molds manufactured before that date may either use the new format as soon as feasible, to minimize the dissemination of misleading information with regard to tire treadwear.; With regard to labels, the requirement that such labels must contai information regarding treadwear grades was suspended effective February 7, 1983. The preamble to the final rule states that manufacturers will be permitted to exhaust inventories of labels which were in existence as of the date of the suspension. Thereafter, manufacturers should begin using labels without treadwear information.; If you have further questions on this matter, please feel free t contact us.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam3436

Open
Mr. J. E. Bingham, British Standards Institution, Maylands Avenue, Hemel Hempstead, Herts HP2 4QS, England; Mr. J. E. Bingham
British Standards Institution
Maylands Avenue
Hemel Hempstead
Herts HP2 4QS
England;

Dear Mr. Bingham: This responds to your letter of June 8, 1981, concerning Standard No 209, *Seat Belt Assemblies*. You are correct that my letter of June 1, 1981, on the abrasion test procedure of the standard should have referred to section 5.1(d), instead of to section 5.2(d).; You also suggested that in the process of clarifying the standard' abrasion requirements, the agency should consider possible modifications to sections 4.2(e) and (f) of the standard. In the process of reviewing the abrasion test requirements, the agency will also examine those other sections to determine what changes should be made.; Finally, you raised the issue of whether the standard, as with othe national and international standards, should have a requirement that conditioned webbing must retain a certain percentage of its unconditioned strength and must also meet the minimum strength requirement for unconditioned webbing. The agency is not aware of any data indicating that our current conditioned strength requirements are insufficient.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam0981

Open
Mr. Carl Monk, 428 Southland Boulevard, Louisville, Kentucky 40214; Mr. Carl Monk
428 Southland Boulevard
Louisville
Kentucky 40214;

Dear Mr. Monk: This is in further response to your letter of January 5, 1973, to Mrs Virginia Knauer, regarding Federal Motor Vehicle Safety Standard (FMVSS) No. 125, *Warning Devices*.; As you already know from Mr. E.T. Driver's letter of January 24, 1973 and previous correspondence from my office and the Department of Transportation, the National Highway Traffic Safety Administration issued the standard as an equipment item that would be suitable for use in all types of vehicles, from trucks to passenger cars.; In issuing the standard, we were concerned with the great variety o devices presently available, which can create confusion and misunderstanding to the motoring public. We were also concerned with wind stability, and your comments were most useful in our consideration of this aspect of the requirements. FMVSS No. 125 is an attempt to achieve a standardized device having a proper balance of the factors affecting shape, size, cost, visibility, wind stability and weight. These are minimum standards and the manufacture and sale of devices that exceed these requirements is not prohibited.; Again, thank you for your comments. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs;

ID: aiam3733

Open
Mr. H. Nakaya, Manager, Mazda (North America) Inc., 23777 Greenfield Road - Suite 462, Southfield, MI 48075; Mr. H. Nakaya
Manager
Mazda (North America) Inc.
23777 Greenfield Road - Suite 462
Southfield
MI 48075;

Dear Mr. Nakaya: This is in response to your letter of July 8, 1983 asking for a interpretation of Motor Vehicle Safety Standard No. 108.; Section S4.2 of SAE Standard J588e *Turn Signal Lamps* establishes minimum distance of 4 inches from the optical axis (filament center) of the front turn signal to the inside diameter of the retaining ring of the headlamp providing the lower beam. You believe that it is not necessary to have a retaining ring on a semi-sealed headlamp and you have asked whether you may substitute the edge of the reflector (as shown on your drawing) to measure the dimension covered by S4.2 of J588e.; The point depicted on your drawing appears to be the inner edge of th reflector, rather than the extreme edge, nevertheless, the 'reflector edge' you have indicated is the approximate location of a retaining ring on a fully sealed headlamp, and is therefore acceptable as a measuring point under Standard No. 108.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam2399

Open
Mr. Byron A. Crampton, Manager of Engineering Services, Truck Body and Equipment Association, Inc., 5530 Wisconsin Avenue, Suite 1220, Washington, DC 20015; Mr. Byron A. Crampton
Manager of Engineering Services
Truck Body and Equipment Association
Inc.
5530 Wisconsin Avenue
Suite 1220
Washington
DC 20015;

Dear Mr. Crampton: This is in response to your letter of August 24, 1976, in which you as whether emergency exits required by a State beyond those required by Standard No. 217, *Bus Window Retention and Release*, are subject to the performance requirements outlined in S4(b) of Standard No. 220, *School Bus Rollover Protection*.; Standard No. 220 requires that all emergency exits provided i accordance with Standard No. 217 must meet certain minimum performance levels during and after the simulated rollover test. Additional emergency exits mandated by State law are not exits 'provided in accordance with Standard No. 217' and, therefore, would not be subject to the requirements of S4(b) of Standard No. 220.; You should note that Standard No. 217, in addition to mandating th provision of certain school bus doors and exits under S5.2, also regulates certain aspects of all emergency exits under other provisions of the regulation.; Sincerely, Frank A. Berndt, Acting 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.