Motor Vehicle Safety Regulations — 217
 (40 lb.) that is applied (a) within the access region for high forces shown in Figure 3B to this section for a side emergency exit door and in Figure 3D to this section for a rear emergency exit door; (b) in any direction from outside the bus; or (c) in an upward direction from inside the bus. (16) Every school bus emergency door release mechanism shall be capable of being operated without the use of remote controls or tools and shall function independently of the vehicle’s power system. (17) Every emergency exit of a bus, other than an emergency door required by subsection (9), shall, after the release mechanism has been operated, be capable of being opened outward manually by an occupant, using the force applications described in subsection (13), to a position providing an opening large enough to allow the unobstructed passage of the ellipsoid described in paragraph (8)(b). (18) Under the conditions set out in subsections (24) and (26), both before and after the window retention test described in subsection (2.1), every emergency exit door of a school bus shall, after the release mechanism has been operated, be capable of being opened outward manually by one person to a position that provides (a) in the case of a side emergency exit door, an opening at least 1 143 mm (45 in.) high and 610 mm (24 in.) wide located so that a vertical transverse plane tangent to the rearmost point of the closest seat back passes through the forward edge of the side emergency exit door; and (b) in the case of a rear emergency exit door, an opening at least 610 mm (24 in.) wide that allows the unobstructed passage of a rectangular parallelepiped that measures l 143 mm (45 in.) in height, 305 mm (12 in.) in width perpendicular to the sides of the bus, and 610 mm (24 in.) in depth parallel to the sides of the bus, the bottom of which remains within 25 mm (1 in.) of the floor at all times during its passage through the opening. (18.1) After insertion of a rectangular parallelepiped described in paragraph (18)(b), a rear emergency exit door or, where there are two rear emergency exit doors, both doors, shall be capable of being closed and latched. (18.2) A school bus that has a GVWR of less than 4 536 kg (10,000 lb.) and two rear doors that function as emergency exit doors shall have (a) a single release mechanism that simultaneously opens both rear doors in a manner such that neither rear door can interfere with the opening of the other rear door under any circumstances; (b) hinging and latching mechanisms that prevent the rear doors from opening when they are closed and fully latched and, under the conditions set out in subsections (24) and (26), a force of 9 000 N (2,000 lb.) is applied perpendicularly to any part of the door other than the window glass by a circular steel plate having a diameter of 150 mm (6 in.) and a thickness of 13 mm (½ in.); and (c) a single interior handle that operates the latching mechanisms and that is situated within 150 mm (6 in.) of a vertical plane equidistant from both sides of the aisle leading to the rear doors when the rear doors are closed and fully latched. (18.3) The rear doors of a school bus referred to in subsection (18.2) shall, under the conditions set out in subsections (24) and (26) and, after undergoing the test specified in paragraph (18.2)(b), be capable of being opened from outside and inside the bus using a force not exceeding 180 N (40 lb.). (19) Every push-out window or other emergency exit in a bus shall, for the purposes of identification and operation, be identified with a label located within 150 mm (six inches) of its release mechanism bearing words in both official languages or an approved symbol that identifies the emergency exit, and followed by concise operation instructions in both official languages, except that school bus emergency exits shall be identified in accordance with the requirements of subsection (23). (20) Where a release mechanism is not located within the occupant space