ID: aiam2225

Dear Mr. Baudhuin: This is in response to your January 29, 1976, letter to Secretar Coleman, concerning problems with your 22 foot Executive 'MINI' Motorhome.; SS 567.4(g)93) and 567.5(a)(5) of 49 CFR Part 567, *Certification* provide that a motor vehicle's Gross Vehicle Weight Rating (GVWR) shall; >>>not be less than the sum of the unloaded vehicle weight, rated carg load, and 150 pounds times the vehicle's designated seating capacity.<<<; Your letter and its enclosures indicate that your vehicle's weight i 9180 pounds, its designated seating capacity is six, and the GVWR specified by Executive is 9000 pounds. From this information, there appears to be a violation by Executive of Part 567. In addition, the possibility that the rear axle may be overloaded under normal conditions of use may constitute a defect related to motor vehicle safety. I have forwarded your letter to our Office of Standards Enforcement for such further action as may be appropriate.; Please note that a final-stage manufacturer is not automaticall prohibited from certifying a GVWR that differs from that specified by the chassis manufacturer. For the purposes of the Federal motor vehicle safety standards and regulations, Executive is free to certify a lower GVWR, provided the above-cited constraint is observed.; The remaining questions presented in your letter are not matters ove which we have jurisdiction, and probably are most appropriately handled by a private attorney.; Sincerely, Frank A. Berndt, Acting Chief Counsel

ID: aiam1469

Dear Mr. Goichman: This responds to your March 26, 1974, request for information on sea belt regulations as they concern reclining passenger seats.; Federal Motor Vehicle Safety Standard No. 208, *Occupant Cras Protection,* requires passenger cars to be equipped with seat belt assemblies, but it does not contain performance requirements to regulate the effectiveness of the belt assembly with the seating system in the reclining position.; Federal Motor Vehicle Safety Standard No. 207, *Seating Systems* specifies minimum safety requirements for motor vehicle seats. The requirements of the standard are based on conventional seat designs that normally incorporate a seat back angle of approximately 25 degrees rearward inclination from the vertical. Standard No. 207 requires that reclining seats be tested in their most upright position and does not require seats to be tested in the reclining position.; The National Traffic and Motor Vehicle Safety Act of 1966 preempt state motor vehicle safety regulations which are not identical to the Federal standards with regard to the same aspect of performance and therefore any state law would be identical to Standards Nos. 207 and 208 on these aspects of performance (15 U.S.C. S1392 (d)).; The engineering staff is not aware of any studies in the area of sea belts and reclining seats.; Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: aiam1744

Dear Mr. Kennebeck: This responds to Volkswagen's December 11, 1974, request fo confirmation that the deletion of the ignition interlock requirement from Standard No. 208, *Occupant crash protection*, does not have the effect of prohibiting installation of an interlock device in a vehicle which meets the requirements of S4.1.2.; Volkswagen will utilize a passive belt system in satisfaction of th requirements of S4.1.2. Passive belts are subject to specific belt assembly requirements of S4.5.3.3. These requirements were recently modified by deletion of the requirement for a belt interlock system (39 FR 38380, October 31, 1974), and passive belt assemblies must now conform to S7.1 (Adjustment), S7.2 (Latch mechanism), and S7.3 (Seat belt warning system).; Your interpretation of these requirements is correct. The Federal moto vehicle safety standards are minimum performance requirements with which each vehicle to which they are applicable must comply. They do not, however, prohibit installation of additional safety devices. As a practical matter, of course, additional devices could not be installed if that installation had the effect of causing the required systems not to comply.; The NHTSA agrees than (sic) an interlock system is important fo ensuring use of a passive belt system.; Yours truly, Richard B. Dyson, Acting Chief Counsel

ID: aiam3369

Dear Mr. Mulligan: This is in response to your letter of October 1, 1980, in which you as whether compliance with 49 CFR 567, Certification, will satisfy the requirements of S4.3 of Federal Motor Vehicle Safety Standard No. 115, 49 CFR 571.115.; Section 4.3 of Federal Motor Vehicle Safety Standard No. 115 require that the vehicle identification number (VIN) 'appear clearly and indelibly upon either a part of the vehicle other than the glazing that is not designed to be removed except for repair or upon a separate plate or label which is permanently affixed to such a part.' S4.3.1 requires each character to appear in a capital, sans serif typeface. In the case of passenger cars and trucks of 10,000 pounds or less GVWR, each character must have a minimum height of 4 mm. S4.4 specifies that the VIN for passenger cars and trucks of 10,000 pounds or less GVWR shall be located within to passenger compartment.; Section 567.4 of Part 567, Certification (49 CFR 567), requires tha the certification label be permanently affixed to the vehicle, and display the vehicle identification number. Consequently, for all vehicles except passenger cars and trucks of 10,000 pounds or less GVWR, compliance with S 567.4 of Part 567 would also effect compliance with S4.3 of Standard No. 115 so long as capital, sans serif typeface was used.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam3105

Dear Mr. Delgado: This responds to your recent letter requesting information concernin Federal and State laws applicable to the manufacture of van seats.; The National Highway Traffic Safety Administration issues safet standards and regulations governing the manufacture of motor vehicles and motor vehicle equipment. Safety Standard No. 207, *Seating Systems* (49 CFR 571.207), specifies performance requirements for seats, their attachment assemblies and their installation to minimize the possibility of seat failure resulting from crash forces. This standard is applicable to seats as installed in vehicles, including vans, but is not applicable to seats as individual pieces of motor vehicle equipment. Therefore, the vehicle manufacturer, not the seat manufacturer, would be responsible for compliance with Standard No. 207. However, under section 151, *et seq*., of the National Traffic and Motor Vehicle Safety Act, a manufacturer of vehicle seats would be responsible for any safety related defects in his products and would be required to notify owners and remedy the defects.; I am enclosing a copy of Safety Standard No. 207 for your information as well as an information sheet that explains where you can obtain copies of all our standards and regulations. You will have to contact the individual States in which you are interested to find out if there are any State or local laws applicable to your business.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam3372

Dear Mr. Mulligan: This is in response to your letter of October 1, 1980, in which you as whether compliance with 49 CFR 567, Certification, will satisfy the requirements of S4.3 of Federal Motor Vehicle Safety Standard No. 115, 49 CFR 571.115.; Section 4.3 of Federal Motor Vehicle Safety Standard No. 115 require that the vehicle identification number (VIN) 'appear clearly and indelibly upon either a part of the vehicle other than the glazing that is not designed to be removed except for repair or upon a separate plate or label which is permanently affixed to such a part.' S4.3.1 requires each character to appear in a capital, sans serif typeface. In the case of passenger cars and trucks of 10,000 pounds or less GVWR, each character must have a minimum height of 4 mm. S4.4 specifies that the VIN for passenger cars and trucks of 10,000 pounds or less GVWR shall be located within the passenger compartment.; Section 567.4 of Part 567, Certification (49 CFR 567), requires tha the certification label be permanently affixed to the vehicle, and display the vehicle identification number. Consequently, for all vehicles except passenger cars and trucks of 10,000 pounds or less GVWR, compliance with S 567.4 of Part 567 would also effect compliance with S4.3 of Standard No. 115 so long as capital, sans serif typeface was used.; Sincerely, Frank Berndt, Chief Counsel

ID: 9920

Mr. Thomas D. Turner
Manager, Engineering Services
Blue Bird Body Company
P.O. Box 937
Fort Valley, GA 31030

Dear Mr. Turner:

This responds to your letter of May 2, 1994, requesting an interpretation of how the term "daylight opening," as used in a recent amendment of Standard No. 217, Bus Emergency Exits and Window Retention and Release, would apply to various exits (57 FR 49413; November 2, 1992, and 57 FR 57020; December 2, 1992).

Your letter references a March 24, 1994 interpretation letter to Mr. Bob Carver of Wayne Wheeled Vehicles. That letter discussed the term "daylight opening" as follows:

The term "daylight opening" is defined in the Final Rule as "the maximum unobstructed opening of an emergency exit when viewed from a direction perpendicular to the plane of the opening." An obstruction in this context would include any obstacle or object that would block, obscure, or interfere with, in any way, access to that exit when opened. In determining the "maximum unobstructed opening of an emergency exit," we would subtract, from the total area of the opening, the area of any portions of the opening that cannot be used for exit purposes as a result of the obstruction. The area measurements would be taken when viewed from a direction perpendicular to the plane of the opening.

Your letter states that this interpretation

represents a drastic change in what we understood from the wording of the final rule ... and what we were told by Rulemaking. We believed and were told that the definition of daylight opening applied to the exit opening itself and did not involve access to the opening. Access to and obstruction of openings are addressed later in the standard in section S5.4.2 School Bus Emergency Exit Extension.

Before answering your specific questions, I would like to respond to these statements. You are correct that S5.4.2 includes requirements related to access to, and obstruction of, exits in that it specifies the minimum opening and the minimum amount of access required for various exits. However, the issue of minimum opening is separate from the issue, addressed in S5.2.3, of the maximum amount of area credited for any opening. Section S5.2.3 specifies the number and type of exits required on school buses. This section states:

The area in square centimeters of the unobstructed openings for emergency exit shall collectively amount to at least 432 times the number of designated seating positions in the bus. The amount of emergency exit area credited to an emergency exit is based on the daylight opening of the exit opening.

Thus, S5.2.3 specifies the maximum amount of area credited for any opening. An interpretation of the term "daylight opening" that allowed credit for the exit opening, regardless of obstructions, would be contrary to the plain language of the definition of that term. Giving credit for obstructed areas would also be contrary to the intent of the final rule, which is to increase the area on larger buses which is available for exit in an emergency.

With respect to your report of receiving an oral interpretation from agency staff, I would also like to emphasize that, to the extent the public has any questions concerning the meaning of any NHTSA standard or regulation, the only agency interpretations which are authoritative and which therefore can be relied upon by members of the public, such as manufacturers, are those issued in writing by the Chief Counsel. We have reminded agency staff not to make formal, or informal, oral statements that might misinterpreted by manufacturers as official agency guidance on which they may safely rely.

Your letter states that the March 24 interpretation "raises other questions regarding the various school bus emergency exits." Your questions and the response to each follows.

By way of background information, NHTSA does not approve motor vehicles or motor vehicle equipment. The following represents our opinion based on the facts provided in your letter.

Rear Emergency Exit Door

a. Section S5.4.2.1(a)(1) ... requires unobstructed passage of a rectangular parallelepiped 30 centimeters deep. It is our rationale and interpretation that a seat back or other interior component that lies forward of this 30 centimeter deep parallelepiped is not an obstruction to the rear emergency door and would not result in a reduction of the area credited to the rear emergency door. (See figure 1a) Is this interpretation correct?

In the case of a rear emergency exit door, the depth requirement in S5.4.2.1(a)(1) reflects a determination that an interior component outside that limit does not render the exit unusable. Therefore, an interior component outside the area bounded by the transverse vertical plane of the exit opening, the two longitudinal vertical planes tangent to the sides of the exit opening, and the transverse vertical plane parallel to and 30 centimeters away from the plane of the exit opening would not be considered an obstruction for determining the area of "daylight opening."

b. School buses are typically equipped with 39-inch (99 cm) wide seats. At the rear emergency door, one of the rear seats is typically shifted forward to provide the clearance required by S5.4.2.1(a)(1). The other rear seat is typically allowed to be near or against the rear wall of the bus to fully utilize the available seating floor space and to provide maximum knee clearance. When viewed from the rear, this seat protrudes into the door opening; and according to the (March 24) interpretation ..., the area of the obstruction would not be credited to the exit. Following the logic of the interpretation, the area of the seat itself and the area above the seat could not be credited. We disagree with the logic of the interpretation that door exits are only used by movement along the floor. If the bus is on its side or top, the exit must be used from different approaches. It is therefore our logic and interpretation that only the actual area obstructed (i.e. the area of the seat and the area below the seat) cannot be credited to the exit. For the case in question, the area above the seat can be used in many accident scenarios and therefore can be credited as "daylight opening." (See figure 1b) Is this interpretation correct?

You are correct that emergency doors will be used by people moving along an interior surface other than the floor if the vehicle is on its side or roof following an accident. As stated in the March 24 interpretation, in determining the amount of daylight opening, you should not credit any area which "cannot be used for exit purposes." In the case of the seat illustrated in incoming letter from Wayne, the area over the seat is 6.12 inches by 12.5 inches. However, in reviewing that letter in light of your question, we now agree that the area over the seat may be usable in some accident scenarios.

For your exit, neither your letter nor figure 1b provide dimensions of the area over the seat. If the area is large enough to be usable in an accident scenario, that area can be credited towards the daylight opening.

c. The rear emergency door on Blue Bird school buses is hinged on the outside, and the top portion of the door is angled forward when the door is closed. When the door is opened and held in the open position by the device required by S5.4.2.1(a)(3)(i), the door protrudes into the exit opening when viewed from a direction perpendicular to the plane of the opening. It is our understanding, based on the interpretation of reference 3, that the protrusion of the door now constitutes an obstruction and the area of the obstruction cannot be credited to the exit area. (See figure 1c) Is this understanding correct?

This is correct.

Emergency Window Exits

The seat backs of school bus seats can protrude into the lower region of side window exit openings. Side window exits when the bus is upright may be used by climbing over the seats. If the bus is on its side or top, the side window exits may be used from different approaches. Since areas of sufficient size above, in front of, and behind a protruding seat back could be used for different parts of the body, (i.e. head, knees, legs) when crawling out a side window exit in different vehicle orientations, it is our logic and interpretation that only the actual area of the seat back in the side window exit opening and the smallest area bounded by the seat back, a horizontal plane tangent to the top of the seat back, and the edges of the exit opening constitute obstructions and cannot be credited to the exit. (See figure 2) Is this interpretation correct?

In your illustrations, the area obstructed by the seat back protruding into the window opening clearly cannot be credited to the daylight opening. Whether area above or forward or rearward of the seat back can be credited depends on whether the size of the area is sufficient to be used in exiting the vehicle. Any of these areas which permits passage of the ellipsoid proposed in a December 1, 1993 notice of proposed rulemaking indicates that these areas clearly should be credited (58 FR 63321, see proposed S5.4.2.1(c)). NHTSA proposed this because it believed it reflected the minimum size window which could be used as an exit.

If not cut off by obstructions from other unobstructed areas of the daylight opening of the window, as viewed in a plan view, it may be possible that smaller areas should also be credited. In all of the illustrations in figure 2, the seat back extends less than halfway up in the opening. Therefore, it appears that the area above the seat would be credited. We also agree that if the seat protrudes near the front or rear edge of the window opening, it is unlikely that the area between the seat back and the nearest edge of the opening would be usable. However, one of your illustrations shows the seat back protruding near the center of the window opening. In such an instance, it may be possible that the area on each side of the seat back is large enough to be usable. For example, a person might use the window by climbing over the seat, with either their legs straddling the seat, or their head and torso over one side of the seat and their legs over the other.

Side Emergency Exit Doors

Following the logic presented above regarding the use of emergency exits in different vehicle orientations, we disagree with the interpretation that area A2 (an area bounded by a horizontal line tangent to the top of the seat back, a vertical line tangent to the rearmost portion of the top of the seat, the upper edge of the door opening, and the edge of the door forward of the seat) ... is not usable. In fact even when using the side emergency door when the vehicle is upright, a person would likely lean over the seat back and hold on to the seat, thus using area A2. Figure 3 enclosed is drawn more to scale than the illustration used in (the March 24 interpretation). We suggest the Agency review this illustration, conduct field research by using the exits in real buses, and then reconsider the interpretation ... regarding side emergency doors. We recommend that area A2 be credited as "daylight opening" for a side emergency door.

As explained in our response to question b on rear emergency exit doors, the area above some seats may be large enough to be credited toward the daylight opening.

Front Service Door

a. The lower portion of the grab handle on many school bus front service doors protrudes into the exit opening when viewed from a direction perpendicular to the plane of the opening. (See figure 4) Based on the (March 24) interpretation ..., we understand that this protrusion now constitutes an obstruction. Is this understanding correct?

This is correct.

b. The front service door of most school buses leads to a stepwell and steps used to enter the bus. On front engine transit style school buses, the steps are typically angled to the rear and the riser to the first step is just a few inches inboard of the door opening. It is our logic and interpretation that steps in a stepwell do not constitute an obstruction and their presence does not reduce the area credited to the entrance door opening. (See figure 4) Is this interpretation correct?

The steps provide the means of using the door, allowing a person to move between the ground and the floor level of the bus. They do not "block, obscure, or interfere with, in any way, access" of occupants descending to the front service door. Therefore, although they are visible in the doorway when the doorway is viewed in a plan view, the steps are not obstructions within the meaning of the definition of daylight opening.

I hope you find this information helpful. If you have any other questions, please contact my staff at this address or by phone at (202) 366-2992.

Sincerely,

John Womack Acting Chief Counsel ref: 217 d:8/24/94

ID: 06-006237drn

ID: 18805.drn

Ms. Barbara Goodman
Associate Director, Pupil Transportation
Commonwealth of Virginia
Department of Education
P.O. Box 2120
Richmond, VA 23218-2120

Dear Ms. Goodman:

This responds to your request for an interpretation of school bus seat back height requirements in Federal Motor Vehicle Safety Standard No. 222, School bus passenger seating and crash protection. I regret the delay in this response.

I understand that you explained to Mr. Charles Hott of our agency that the C. E. White Company manufactures school bus seats that are integrated with child restraints, and which have 711 millimeter (28 inch) high seat backs. While you are interested in having some of these seats installed in school buses along with standard school bus seats with 508 millimeters (20 inch) high seat backs, you ask about Standard 222's requirements that apply to a 711 millimeter (28 inch) high seat back. You pose five questions, which we answer below.

1. "If a C. E. White or similar type seat, with a 39 inch seat cushion width and a 28 inch seat back height is installed in a school bus, what is the federal requirement for the seat back/barrier immediately in front of the [tall] C. E. White seat?"

We believe you are asking whether the height of the seat back or barrier in front of the tall seat has to be at least 508 millimeters (20 inches) or at least 711 millimeters (28 inches). As explained below, assuming the width of the seat bench in front of the C.E. White type seat is 990 millimeters (39 inches), the seat back or restraining barrier in front of the C.E. White type seat has to be at least 508 millimeters (20 inches), not 711 millimeters (28 inches).

Seat back height. The minimum height required of seat backs is specified in S5.1.2 of Standard 222. S5.1.2 states: "Each school bus passenger seat shall be equipped with a seat back that, in the front projected view, has a front surface area above the horizontal plane that passes through the seating reference point, and below the horizontal plane 508 mm [20 inches] above the seating reference point, of not less than 90 percent of the seat bench width in millimeters multiplied by 508." Simply stated, this section requires seat back heights of at least 508 millimeters (20 inches) above the seating reference point.⁽¹⁾ Standard 222 does not require the seat back to be taller if it is in front of a school bus seat that has a 711 millimeter (28 inch) high seat back.

Restraining barrier height. Paragraph S5.2 of Standard 222 requires each vehicle to be equipped with a restraining barrier forward of any designated seating position that does not have the rear surface of another school bus passenger seat within 610 mm (24 inches) of its seating reference point.

The minimum height for restraining barriers is specified in S5.2.2 of Standard 222. That section states: "The position and rear surface area of the restraining barrier shall be such that, in a front projected view of the bus, each point of the barrier's perimeter coincides with or lies outside of the perimeter of the seat back of the seat for which it is required."

In an interpretation letter of April 8, 1977, to Wayne Corporation (copy provided), this agency interpreted the restraining barrier requirement to mean that a restraining barrier must only coincide with or lie outside of the seat back surface required by S5.1.2. Thus, in a front projected view of the bus, each point of the barrier's perimeter would have to coincide with or lie outside of the perimeter of a seat back with a height of 508 millimeters (20 inches) (assuming the width of the bench seat for which the seat back is required is 990 millimeters (39 inches)).

2. "If a C. E. White or similar seat, with a 28 inch seat back height, is installed as the rear seat of a sixty four passenger school bus, will each of the seat backs in front of each seat require a 'New York-type' seat back (28 inch height)."

As answered above, the seat backs in front of the tall C.E. White type seat do not have to be 711 millimeters (28 inches) in height simply because they are positioned in front of a seat that has a 711 millimeter (28 inch) seat back. The size of a seat back depends on the width of the seat for which it provides a back.

3. "Can a school bus body be configured with different heights of seat backs installed in a single unit."

By "in a single unit," I will assume you mean "in one school bus." Alternatively, you might mean "in one row of seats." Our answer is that nothing in Standard 222 specifies that in a school bus or row of seats, each seat back must be of the same height. However, each passenger seating position must have a seat back that meets S5.1.2 and have in front of it a seat back that meets S5.1.2, or a restraining barrier that meets S5.2.2.

4. "Can seat back heights exceed the federal requirement, and if so, how does this impact other seats within the same unit?"

As previously stated, the area and height of any seat back depends on the width of the seat bench for which it provides a back, not on the height of other seat backs. Each passenger seating position must have a seat back that meets S5.1.2, and must be faced with a seat back or a restraining barrier.⁽²⁾

5. "If the first seat has a short (30 inch width) seat cushion, what is the federal requirement for both the barrier height and width and the seat back height and width."

You explained to Dorothy Nakama of my staff that this question asks about the situation where the first row of seats has a 762 millimeter (30 inch) width and the second row directly behind the first row has a 990 millimeter (39 inch) width. There is a restraining barrier in front of the first row. You are concerned about how a child sitting in the second row in the 228 millimeter (9 inch) section not faced by a seat back is to be protected.

The child sitting in the 228 millimeter (9 inch) section in the second row must be protected in part by a restraining barrier. Referring again to the letter of April 8, 1977 to Wayne Corporation, the combination of the restraining barrier and the seat back of the first row seat must coincide with or lie outside of the perimeter of the second row's required seat back surface.

I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosures
ref:222
d.4/26/99

1. For a 990 millimeter (39 inch) bench seat, the seat back must have a front surface area at least .9(990) multiplied by 508, or 452,628 square millimeters (702 square inches).

2. An issue that may be implicit in your question is whether States may require a seat back height greater than 508 millimeters (20 inches). Our position is that any State requirement relating to seat back height, other than one identical to the Federal formula that establishes a minimum height of 508 millimeters (20 inches), is preempted under 49 USC 30103(b) of our statute. However, our statute does not prevent governmental entities from specifying additional safety features in vehicles purchased for their own use. Thus, for public school buses, a State may specify a seat back higher than 508 millimeters (20 inches). See March 23, 1976 to Mr. Martin V. Chauvin, copy enclosed.

ID: 16614-1.pja

Mr. Shane K. Lack
Mechanical Engineer
Human Factors Division
National Transportation Safety Board
490 L'Enfant Plaza East, SW
Washington, DC 20594

Dear Mr. Lack:

This responds to your request that we review your draft summaries and interpretations of Federal Motor Vehicle Safety Standards 205 (49 CFR 571.205, Glazing materials) and 217 (49 CFR 571.217, Bus emergency exits and window retention and release). We apologize for the delay in responding.

Because your documents are lengthy (36 pages) and contain so many statements, questions, and interpretations, we are unable to address each individual point in this letter. Instead, we will confirm that, in general, your summaries and interpretations of our standards are correct. We offer the following answers to your questions and corrections to a few of your interpretations, with reference to the page number and line number of your summary. For brevity, we have paraphrased the relevant portions of your letter in italics.

Federal Motor Vehicle Safety Standard No. 205, Glazing materials

Questions on page 1, lines 1 through 9, and lines 22 through 27: Will any material that meets the tests for a specific item of glazing be considered to be that kind of glazing, or do materials specifications (e.g., rigid plastic) restrict the choice of material?

The answer to the first part of your question is yes. The material of which the glazing is constructed is not specified. Both Standard 205 and the American National Standard, Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways -- ANSI Z26.1-1977 (hereafter referred to as ANSI Z26.1, which is incorporated by reference in the CFR) may refer to specific kinds of glazing in headings. Examples of this are in paragraph S5.1.2.3 of the standard, which refers to "flexible plastics," and the column headings of Table 1 in ANSI Z26.1, which lists materials such as "laminated glass." These headings are for illustrative purposes only, to indicate the material and construction that typically is used to meet the enumerated tests. See note 1 to Table 1 in ANSI Z26.1, which specifically states that future materials that meet the enumerated tests may be used. Therefore, any material that meets all the tests for a particular item of glazing complies with the standard, regardless of composition or construction.

Question on line 28 through 33: What about paragraph S5.1.2.2, which in the text of the standard itself seems to restrict item 12 glazing to safety plastics?

Again, the mention of safety plastics is illustrative. The words "safety plastics" should not have been included in the standard. However, the performance-based method (i.e., whatever meets the tests) of determining compliance is maintained even for item 12 glazing.

Question on page 1, lines 34 and 35, and page 2, lines 1 and 2: Are the glazing materials approved for the side windows of buses the same regardless of the gross vehicle weight rating and whether the bus is a school bus or a non-school bus?

The answer to both questions is yes.

Question on page 2, line 8: Is the list on lines 9 through 22 showing approved glazing types for side windows of buses correct?

The list of approved glazing types on page 2 is correct.

Question on page 2, line 25: Does each piece of glazing material have to be stamped with "AS" followed by the item no. of the glazing?

Yes.

Question on page 2, line 26: Does Standard No. 205 allow glazing materials that shatter to be placed in the side windows of buses, as long as those materials shatter into small pieces.

Yes.

Question on page 2, line 28: Does Standard No. 205 require a measurement of the dynamic force deflection curve of glazing materials?

No, it does not.

Federal Motor Vehicle Safety Standard No. 217, Bus emergency exits and window retention and release

Interpretation at page 1, line 27: To be counted as an emergency exit, an exit must be in compliance with all emergency exit requirements for that type of exit.

We assume when you say "to be counted" you mean whether a particular exit would count for determining if the bus has the correct number of exits specified in Standard No. 217. When conducting a compliance inspection of a new vehicle, the National Highway Traffic Safety Administration (NHTSA) would normally have the manufacturer's certification data showing which exits are designated as emergency exits. If an exit did not comply in some way, this agency would not "uncount" that exit for meeting exit number and exit area requirements. Instead, the vehicle would be considered to have failed only the requirements that were not fulfilled. For example, if an otherwise compliant exit were not labeled, the bus would fail only the S5.1.1 labeling requirement. The area for that exit would still be counted for meeting the emergency exit number and area requirements.

Interpretation on page 1, line 31: The minimum size of an emergency exit window in a non-school bus is the area of an ellipsoid having a major axis parallel to the ground of 50 cm and a minor axis of 33 cm. This minimum total area of an emergency exit on a non-school bus is 510.5 square centimeters.

The first sentence of your interpretation is correct. Your computation in the second sentence is incorrect. The minimum emergency exit opening computes to 1296 sq. cm for a 33cm X 50cm ellipsoid. The area of an ellipse = 3.14 times the product of the major and minor semi-axes.

Interpretation on page 2, line 24: For non-school buses with a GVWR > 10,000 lb, there is no prohibition against placing side emergency exits vertically above one another.

While it is true that there is no prohibition explicitly stated in the standard, NHTSA interprets its regulations consistently with their purposes. The purpose behind the emergency exit requirements, which is clearly reflected paragraph S2 and in its preambles on the subject, is to provide readily accessible emergency egress. It is highly unlikely that a manufacturer would actually place emergency exits in such an unusual configuration. If it did, NHTSA would not regard the emergency exit placed on top of another as being accessible, and would not count it toward meeting the requirements.

Interpretation on page 2, lines 29 through 30: There are no guidelines on lateral or longitudinal placement of roof emergency hatches.

Paragraph S5.2.1 allows manufacturers of non-school buses to meet the specifications for non-school buses in S5.2.2 or the specifications for school buses in S5.2.3. If S5.2.2 is followed and a roof exit is needed because a rear exit cannot be provided, then paragraph S5.2.2.2 specifies that the roof exit is to be located in the rear half of the bus. If S5.2.3 is followed, then S5.3.2.2(b) specifies both the longitudinal and lateral position of all roof exits.

Interpretation on page 4, line 1: An emergency release mechanism is defined in previous NHTSA interpretations as a mechanism that prevents an exit from opening.

We do not know to which interpretation you are referring. A computerized search of all our previous interpretation letters did not reveal an interpretation with those words. It is true, however, that the provisions specifying that the release mechanisms can only be actuated by applications of a certain magnitude of force in certain directions are designed to prevent inadvertent opening of an exit.

I hope this is helpful. Again, my sincere apologies for the delay in our reply.  If you have any further questions, please feel free to contact us at (202) 366-2992.

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:205# 217
d.2/17/99