Emergency windows and roof exits

(a) All school buses must be equipped with the minimum amount of emergency exits required by FMVSS-217 as determined by the vehicle seating capacity. Non-required emergency exits shall conform to the requirements of FMVSS-217 for required emergency exits. (b) On Type D rear-engine buses, the rear window shall be designed so as to be opened from either the inside or the outside. It shall be hinged at the top and be equipped with a linkage or mechanism that shall automatically hold the opened window against the force of gravity at a minimum hinge opening angle of sixty (60) degrees (+ or - 5°) measured from the closed window position. Such linkage or mechanism shall not prevent the window from opening a full ninety (90) degrees due to gravitational forces should the bus be inverted. The outside handle shall be non-detachable and designed to discourage hitching. A gas spring or mechanism shall provide a counterbalancing force sufficient to reduce the effort necessary to open the window to ten (10) pounds or less out to the full sixty (60) degree opening position. (c) All school buses equipped with emergency roof exits shall have a minimum opening of 22x23 inches and shall not cause any roof bows to be cut or manufactured discontinuously. (d) Lettering meeting the requirements of FMVSS 217 shall appear on both the inside and outside of the emergency exits. It shall include latch operating instructions on the inside. The words "Emergency Exit" shall appear on both the inside and outside of emergency windows, either at the top of, directly above or at the bottom of the emergency window. The designation for roof exits shall be located on the inside surface. In the absence of adequate space, such lettering may appear at the top of the glass.