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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 13081 - 13090 of 16513
Interpretations Date
 search results table

ID: nht78-3.24

Open

DATE: 09/22/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your August 21, 1978, letter asking whether you are permitted under Standard No. 217, to place the emergency exit sign at the bottom of a rear emergency window exit.

The National Highway Traffic Safety Administration has permitted the use of the emergency exit sign to be on the top half of rear emergency doors. This has permitted the sign to be located just below the glass on the rear emergency door. Although your location of the exit sign is not on top of the rear emergency window exit, its location is similar to the location of the exit sign on a rear emergency door. Since the location of the sign is on the emergency window exit and is within the top half of the bus, the agency has determined that this location complies with the requirements.

SINCERELY,

Thomas BUILT BUSES, INC.

August 21, 1978

Office of the Chief U. S. Department of Transportation

Attn: Roger Tilton

Subject: MVSS - 217. Section S5.5.3 - School Bus

Reference is made to our conversation relative to the above.

In that conversation, we discussed the location of the sign "Emergency Exit".

We are enclosing a photo of what we were describing the location of the sign. According to the writer, the location as depicted in the photo is permissable. As we pointed out, this location, in our opinion more closely covers the intent of the section.

On this point, we understand you concurred. We would appreciate confirmation of this concurrance for the record.

James Tydings, Specifications Engineer

(Graphics omitted)

ID: nht78-3.25

Open

DATE: 10/02/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your August 25, 1978, letter asking what the term "normal nighttime illumination" mean in Standard No. 217, Bus Window Retention and Release.

The term "normal nighttime illumination" is found in paragraph S5.5.2 of the standard. This section requires that all interior exit instructions be legible when the only source of light is the normal nighttime illumination of the vehicle. The term, as used in this paragraph, means that exist instructions must be visible with the normal interior vehicle lighting that is in use when the bus is moving. Interior vehicle lighting may include, for example, reading lamps and overhead lights.

SINCERELY,

Thomas BUILT BUSES, INC.

August 25, 1978

Office of the Chief Counsel U.S. Department of Transportation

Attn: Roger Tilton

Subject: MVSS 217, Section S5.5.2 - School Bus

Dear Mr. Tilton:

We are inquiring if a definition has been given to the phrase "Normal Nighttime Illumination".

Our interpretation is that the interior lights in the vehicle constitude "Normal Nighttime Illumination".

We are most interested in hearing from you in this matter.

James Tydings, Specifications Engineer

ID: nht78-3.26

Open

DATE: 02/14/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr,; NHTSA

TO: Thomas Built Buses

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your December 8, 1977, letter asking for an interpretation of the term "passenger compartment" as used by the National Highway Traffic Safety Administration (NHTSA) in Standard No. 217, Bus Window Retention and Release.

Standard No. 217 requires that a school bus side emergency door be located in the rear half of the bus passenger compartment. The NHTSA interprets the term "passenger compartment" to mean the area from the windshield to the back of the bus.

In a companion question, you ask whether it would be permissible for a small portion of a side emergency door, installed pursuant to S5.2.3.1(b), to fall within the front half of a bus as long as most of the door is within the required rear half of the passenger compartment. The answer to your question is no. The emergency door must be totally located within the rear half of the passenger compartment.

SINCERELY,

THOMAS BUILT BUSES, INC.

December 8, 1977

Office of the Chief Counsel U.S. Department of Transportation

Attn: Roger Tilton

Subject: School Buses - Emergency Door, Location of

Re: Federal Motor Vehicle Safety Standard 217, Bus Window Retention and Release, Section S5.2.3.1(b)

The above referenced section states: "One emergency door on the vehicle's left side that is in the rear half of the bus passenger compartment . . . .etc."

Several questions have arisen regarding the quoted portion of the standard, and we would appreciate an answer to these questions. We have included prints to help explain our inquiries.

1. Passenger Compartment: From what point to what point longitudinally is the passenger compartment measured? As can be seen on the print the passenger compartment may vary depending on what is definition of the passenger compartment.

Is it from the windshield to the rear of the bus (1/2L + 1/2L), or from the back of the front barrier to the rear of the bus? (1/2R + 1/2R) NOTE: For clarity, we have shown these measurements on opposite sides of the bus. Also for your information the State of New York measures (1/2L + 1/2L) or glass to glass as it is commonly called.

Our prime purpose of the inquiry is that the State of Washington requires that the side emergency door be located in front of the rear axle. In certain cases this is impossible, and still meet your requirement of FMVSS 217-S5.2.3.1(b). We realize that Federal Standards take precedent over the State Standard yet on certain models, due to the module construction, a portion of the door impinges upon the forward section of the passenger compartment. Is this permissible?

Areas marked W/H are wheelhouses, and no side emergency door may be installed in these area and comply with FMVSS 217-S5.4.2.1.(b).

If we may be of further assistance, kindly advise.

James Tydings, Specifications Engineer

ID: nht78-3.27

Open

DATE: 02/14/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Ward Industries, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your December 14, 1977, letter asking whether the rear push out window emergency exit option in Standard No. 217, Bus Window Retention and Release, is limited to rear-engine school buses.

The National Highway Traffic Safety Administration (NHTSA) initially proposed that this option be restricted to rear-engine school buses. Comments to that rulemaking, however, persuaded the agency to permit the use of these emergency exits on all school buses regardless of the location of the engine or passenger seats. That determination was explained in the preamble to the final rule published on June 3, 1976 (41 FR 22356) (enclosed).

I trust that this fully responds to your question.

SINCERELY,

WARD Industries, Inc.

December 14, 1977

Joseph Levin, Chief Office of Chief Counsil National Highway Traffic Safety Admn.

Re: FMVSS 217

Dear Mr. Levin:

Paragraph S5.2.3.1(b) and referenced Figure 3C of FMVSS 217 permits the use, as a manufacturer's option, one emergency door on the vehicle left side and a pushout rear window (16 inches x 48 inches).

Does this standard permit the use of this rear window in other than rear engine type vehicles? We have had requests from schools to manufacture a conventional school bus equipped with the above combination of emergency exits.

Since Figure 3C of referenced FMVSS shows a rear shelf between the rear seat and the rear wall, does this prohibit the use of the rear pushout window when seats are located all the way to the rear wall?

An early response to this petition for clarification will be appreciated.

E. M. Ryan, Chief Design Engineer

cc: BUD RYAN; JAMES STRAUB

ID: nht78-3.28

Open

DATE: 03/22/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Midland Machinery Company, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Midland Machinery Company's February 20, 1978, request for confirmation that Standard No. 121, Air Brake Systems, does not apply to an air-braked trailer that carries no cargo and consists entirely of a portable mixing plant.

Section S3 of Standard No. 121 contains an exclusion for any trailer whose unloaded vehicle weight is not less than 95 percent of its gross vehicle weight rating (GVWR). "Unloaded vehicle weight" means the weight of a vehicle with maximun capacity of all fluids necessary for operation of the vehicle, but without cargo or occupants. You state that the portable mixing plant trailer carries no cargo, and it would thus be excluded from the requirements of Standard No. 121.

Enclosed are copies of Standard No. 108 and 120, along with an information sheet that explains how copies of these and other NHTSA regulations may be obtained.

ID: nht78-3.29

Open

DATE: 04/14/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Grove Manufacturing Co.

TITLE: FMVSS INTERPRETATION

TEXT:

NOA-30

Mr. R. G. Wilkins Product Safety and Reliability Grove Manufacturing Co. Shady Grove, Pennsylvania 17256

Dear Mr. Wilkins:

This responds to your recent letter asking whether plastic glazing materials may be used on the superstructure operator cabs of mobile construction cranes. Apparently, the upper superstructure cab is used only for craning operations and is distinct from the cab used to drive the crane over public highways.

Under Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR Part 571.205), plastic glazing may be used only in locations to the rear of the driver in trucks or truck tractor cabs and only at levels not requisite for driving visibility. Therefore plastic glazing could not be used in the windshield or windows to the right or left of the driver in the main driving cab of the mobile crane. It is our interpretation, however, that the superstructure operator cab is, effectively, to the rear of the driver when the vehicle is being used on the highway and could be equipped with plastic glazing materials meeting the requirements of Standard No. 205. This interpretation assumes that the operator cab cannot be used to drive the mobile crane on the highway. If the operator cab could be used as the driving cab, plastic glazing could only be used in locations to rear of the driver at levels not requisite for driving visibility.

Please contact this office if you have any questions concerning this interpretation.

Sincerely,

Joseph J. Levin, Jr. Chief Counsel

Ref: PSR-2727

February 23, 1978

U.S. Department of Transportation National Highway Traffic Safety Administration (NHTSA) Washington, D.C. 20590

Attention: Office of Legal Counsel

Subject: Request for Interpretation on Use of Plastic Glazing Materials on Superstructure Cabs Applicable to Mobile Hydraulic Cranes.

Reference: (a) FMVSS-205 (b) Z26.1-1966

Dear Sir:

For the past few years our distributors, predicated on user input, has requested Grove to consider the installation of various plastic glazing materials in our (upper) superstructure operator cabs to aid in the prevention of vandalism at their yards and construction job-sites as well as reducing machine "down-time" for glass replacement.

For your edification, we have included two typical carrier-mounted hydraulic crane sales brochures to be utilized as an aid to better understand our design characteristics and positioning of our superstructure cabs. Grove Manufacturing Company feels that an official interpretation from your office is required prior to any action on our part to install a glazing material other than glass inasmuch as Grove does certify to meet all Federal Motor Vehicle Safety Standards (FMVSS) on the date of manufacture.

Our interpretation of FMVSS-205 precludes the use of plastic materials as glazing other than to the rear of the driver, however, our superstructure cab is utilized strictly for craning operations on an off-highway configuration and while "roading" the crane over public highways the upper mode is unoccupied.

If clarification or further information is required to aid in forming an official NHTSA opinion on this matter, please do not hesitate to contact us.

May we thank you in advance of any consideration given in this matter.

Very truly yours,

GROVE MANUFACTURING COMPANY

R. G. Wilkins Product Safety & Reliability Analyst

RGB/cds

Encl.

ID: nht78-3.3

Open

DATE: 09/13/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Department of Transportation - Rhode Island

TITLE: FMVSS INTERPRETATION

TEXT: I regret the delay in answering your letter. This responds to your questions concerning the recent amendment of Safety Standard No. 205, Glazing Materials, that permits the use of rigid plastics in the side windows of buses. Specifically, you ask whether the amendment includes school buses and whether plastic glazing would be allowed in entrance doors and in rear emergency doors of school buses.

Safety Standard No. 205 was amended to permit the use of rigid plastic glazing in all doors and windows of buses, except windshields or in windows to the immediate right or left of the driver (42 FR 61465, December 5, 1977). This amendment is applicable to school buses, since they are a special sub-category of "bus." The plastic glazing would not be allowed in a bus entrance door since this would constitute a "window to the immediate right" of the driver. Plastic glazing would be allowed in the rear emergency door, however, since that location was not excepted in the amendment.

Please contact Hugh Oates of this office if you have any further questions (202-426-2992).

Sincerely,

ATTACH.

STATE OF RHODE ISLAND AND PROVIDENCE PLANTATIONS

Department of Transportation

July 12, 1976

Joseph J. Levine -- Chief Counsel, N.H.T.S.A.

RE: Docket No. 71-1; Notice 06 Final Rule, Glazing Materials. Amended Safety Standard No. 205

Dear Sir:

During a recent telephone conversation with Ms. Nancy Egar it was suggested that I submit my request for an interpretation of the above mentioned amendment relative to glazing material to be used with the use of school buses.

In preparing our school bus inspection for the start of the September 1978 school year, I am in need of guidelines in interpreting whether or not rigid plastic glazing material is allowed for use in the school buses in particular locations such as the rear emergency door which is a visible location via the rear view mirror and the entrance door which is a visible location for children prior to the door being opened. Further to this, the overall amendment includes buses but I was wondering if school buses per say may be exempt in the interpretation of the word bus.

I would appreciate your reviewing the above comments and notifying me in writing as to the N.H.T.S.A. interpretation relative to these questions as soon as possible so that I in turn may respond to the school bus owners before August 15, 1978.

Sincerely yours, Alfred Massarone, Chief -- MOTOR VEHICLE SAFETY AND EMISSION CONTROL DIVISION

ID: nht78-3.30

Open

DATE: 12/13/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Cars & Concepts, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your December 4, 1978, letter concerning the applicability of Safety Standard No. 205, Glazing Materials, to applied windshield tint bands.

I am enclosing copies of two previous letters of interpretation by the agency regarding polyester films that appear to be similar to the product you describe. I think these letters will answer all of your questions. If not, please contact Hugh Oates of my office at 202-426-2992.

ID: nht78-3.31

Open

DATE: 06/14/78

FROM: AUTHOR UNAVAILABLE; Joseph J. Levin Jr.; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your April 4, 1978, letter asking several questions concerning the applicability of the Federal school bus safety standards to your vehicles.

First you ask whether a driver is considered a passenger for computation of designated seating positions and whether he is included in the computation of vehicle capacity. The term "passenger" is not used in the definition of designated seating position in Part 571.3 of our regulations. Designated seating position uses the term "person" in its definition, and a driver is considered a person for both the computation of designated seating positions and vehicle capacity.

On a related point concerning designated seating positions, you ask whether wheelchairs are considered designated seating positions or auxiliary seats. Wheelchair seating positions are not designated seating positions and, therefore, are not required to comply with standards that apply to designated seating positions. However, wheelchair positions are counted in determining vehicle seating capacity for the determination of the type classification of a vehicle.

In your second question, you ask what is the proper vehicle classification for a standard design school bus that carries fewer than 10 persons. This type of vehicle would be classified as a multipurpose passenger vehicle. As a multipurpose passenger vehicle, all fixed seating positions would be required to have seat belts. Wheelchair positions, since they are not designated seating positions, are not required to have seat belts.

In a question pertaining to the above-mentioned vehicle type, you ask whether it can be classified as a school bus if it complies with all of the school bus safety standards. The answer to your question is no. This vehicle would be a multipurpose passenger vehicle. As a multipurpose passenger vehicle it must be certified in compliance with all of the standards applicable to that vehicle type. You are not prohibited from marking the vehicle as a school bus, however, with school bus paint, lighting, and lettering. Such markings do not change the vehicle type from multipurpose passenger vehicle to school bus.

SINCERELY,

April 4, 1978

Joseph J. Levin Chief Counsel National Highway Traffic Safety Administration

Dear Mr. Levin:

As a followup to a conversation by Bill Milby and Roger Tilton on March 29, 1978, I am writing to seek clarification of several terms and their application. The terms are as defined in Part 571-1 under Definitions.

1. With respect to "designated seating capacity" and "designated seating position":

a. Is the driver included as a passenger? Must he be counted for vehicle capacity?

b. Are wheelchairs considered auxiliary seats or must they be included as designated seating positions for certification?

2. What is the proper vehicle classification for a vehicle of "traditional" school bus styling with seating capacity for less than ten persons?

3. If proper classification for item 2 is "multipurpose passenger vehicle", must fixed seating positions and wheel chair positions have seat belts?

4. If the vehicle has seating capacity for less than 10 persons, may it be classified as a "school bus" provided it meets all FMVSS applicable to schoolbuses?

5. If the vehicle has seating capacity for less than 10 persons and is classified as a MPV, can it be painted yellow and black and carry children to and from school and be identified with the letters "SCHOOL BUS"?

I am looking forward to your interpretation.

Thank you.

R. L. DuMond Staff Engineer

ID: nht78-3.32

Open

DATE: 05/01/78 EST

FROM: AUTHOR UNAVAILABLE; Joseph J. Levin Jr.; NHTSA

TO: Peabody Galion

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your recent letter asking whether a stand-up, right-hand drive position in a truck with a mounted side loader would be considered a designated seating position under Federal safety regulations.

The answer to your question is no. Under 49 CFR Part 571.3, "designated seating position" is defined as:

"any plan view location intended by the manufacturer to provide seating accommodation while the vehicle is in motion, for a person at least as large as a fifth percentile adult female, except auxiliary seating accommodations such as temporary or folding jump seats."

Since the driving position in question is a stand-up position in which no seat is provided, it obviously cannot be a location intended by the manufacturer to provide "seating accommodation."

Feel free to contact this office if you have any further questions.

Sincerely,

ATTACH.

March 14, 1978

Office of Chief Counsel -- National Highway Traffic Safety Administration

Gentlemen:

Peabody Solid Wastes Management is a division of Peabody International Corporation. Our division manufactures a complete line of Solid Waste Handling Equipment including truck mounted Front Loaders, Rear Loaders, Side Loaders, Stationary Compactors, Transfer Trailers and Transfer Stations.

We are now designing a new truck mounted Side Loader. The concept of this Side Loader has been used on the West coast for a number of years. It is a very efficient, low labor cost system for collecting household refuse, since only one man is required.

To make this system workable requires considerable modifications to a standard tilt cab chassis. One of the principle modifications is a stand up right hand drive position for the operator. This enables him to quickly exit and enter the cab as he picks up curb side refuse. The operator uses this drive position only when on his route, and usually at speeds of less than 10 miles per hour. When traveling over highways, he uses the normal left hand driving position. Enclosed is a sketch SK-7024-C which illustrates a typical cab conversion.

Peabody wants to be certain that we can certify this converted cab to all N.H.T.S.A. regulations that apply. This conversion was discussed with the following on March 7, 1978.

Martz Elliott - Office of Crash Avoidance Robert N. Williams - Office of Crash Worthiness Guy Hunter - Office of Crash Worthiness Roger Tilton - Office of Chief Counsel

We are requesting a ruling from your office that the right hand drive position would not be construed as a designated seat.

We would appreciate anything you could do to expedite your ruling since much of our program depends on this.

Very truly yours, Glenn S. Park Vice President -- Director of Engineering, PEABODY GALION

enc. 2

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.