[Code of Federal Regulations] [Title 49, Volume 4] [Revised as of October 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 49CFR393.61] [Page 1075-1076] TITLE 49--TRANSPORTATION CHAPTER III--FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 393--PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION--Table of Contents Subpart D--Glazing and Window Construction Sec. 393.61 Window construction. (a) Windows in trucks and truck tractors. Every truck and truck tractor, except vehicles engaged in armored car service, shall have, in addition to the area provided by the windshield, at least one window on each side of the [[Page 1076]] driver's compartment, which window shall have sufficient area to contain either an ellipse having a major axis of 18 inches and a minor axis of 13 inches or an opening containing 200 square inches formed by a rectangle 13 inches by 17\3/4\ inches with corner arcs of 6-inch maximum radius. The major axis of the ellipse and the long axis of the rectangle shall not make an angle of more than 45 degrees with the surface on which the unladen vehicle stands; however, if the cab is designed with a folding door or doors or with clear openings where doors or windows are customarily located, then no windows shall be required in such locations. (b) Bus windows. (1) Except as provided in paragraph (b)(3) of this section a bus manufactured before September 1, 1973, having a seating capacity of more than eight persons shall have, in addition to the area provided by the windshield, adequate means of escape for passengers through windows. The adequacy of such means shall be determined in accordance with the following standards: For each seated passenger space provided, inclusive of the driver there shall be at least 67 square inches of glazing if such glazing is not contained in a push-out window; or at least 67 square inches of free opening resulting from opening of a push-out type window. No area shall be included in this minimum prescribed area unless it will provide an unobstructed opening sufficient to contain an ellipse having a major axis of 18 inches and a minor axis of 13 inches or an opening containing 200 square inches formed by a rectangle 13 inches by 17\3/4\ inches with corner arcs of 6- inch maximum radius. The major axis of the elipse and the long axis of the rectangle shall make an angle of not more than 45[deg] with the surface on which the unladen vehicle stands. The area shall be measured either by removal of the glazing if not of the push-out type or of the movable sash if of the push-out type, and it shall be either glazed with laminated safety glass or comply with paragraph (c) of this section. No less than 40 percent of such prescribed glazing or opening shall be on one side of any bus. (2) A bus, including a school bus, manufactured on and after September 1, 1973, having a seating capacity of more than 10 persons shall have emergency exits in conformity with Federal Motor Vehicle Safety Standard No. 217, part 571 of this title. (3) A bus manufactured before September 1, 1973, may conform to Federal Motor Vehicle Safety Standard No. 217, part 571 of this title, in lieu of conforming to paragraph (b)(1) of this section. (c) Push-out window requirements. (1) Except as provided in paragraph (c)(3) of this section, every glazed opening in a bus manufactured before September 1, 1973, and having a seating capacity of more than eight persons, used to satisfy the requirements of paragraph (b)(1) of this section, if not glazed with laminated safety glass, shall have a frame or sash so designed, constructed, and maintained that it will yield outwardly to provide the required free opening when subjected to the drop test specified in Test 25 of the American Standard Safety Code referred to in Sec. 393.60. The height of drop required to open such push-out windows shall not exceed the height of drop required to break the glass in the same window when glazed with the type of laminated glass specified in Test 25 of the Code. The sash for such windows shall be constructed of such material and be of such design and construction as to be continuously capable of complying with the above requirement. (2) On a bus manufactured on and after September 1, 1973, having a seating capacity of more than 10 persons, each push-out window shall conform to Federal Motor Vehicle Safety Standard No. 217, (Sec. 571.217) of this title. (3) A bus manufactured before September 1, 1973, may conform to Federal Motor Vehicle Safety Standard No. 217 (Sec. 571.217) of this title, in lieu of conforming to paragraph (c)(1) of this section. [33 FR 19735, Dec. 25, 1968, as amended at 37 FR 11677, June 10, 1972]