Motor Vehicle Safety Regulations — 217
217 (1) Subsections (2) and (2.1) do not apply to a windshield or a window of a size such that the length of the smallest chord along the surface of the glazing passing through the centroid is less than 200 mm (8 in.). (2) Every window glazing and surrounding window frame in a bus shall be retained by its surrounding structure in a manner that prevents the formation of an opening large enough to admit the passage of a sphere with a diameter of 100 mm (4 inches) that is pressed through the opening by a force of 22 N (5 pounds) including the weight of the sphere, when the window is tested according to the procedure set out in subsection (2.1). (2.1) Under the conditions set out in subsections (24) and (25), an increasing force shall be applied to the head form specified in Figure 4 to this section to cause it to move at a velocity of 51 mm per minute (2 in. per minute) from a point inside the vehicle that is at the centroid of the window glazing in a direction that is outward and perpendicular to the undisturbed surface of the glazing until one of the following occurs: (a) the force equals 5 300 N (1,200 lb.); (b) cracks have developed that penetrate to a depth of at least 80 per cent of the thickness of the glazing and radiate outward from the point of contact of the head form to two or more points at the window frame; (c) the glazing shatters; or (d) the inner surface of the glazing at the centroid has moved perpendicularly to the undisturbed surface of the glazing a distance equal to the square root of the length of the smallest chord along the surface of the glazing passing through the centroid divided by (i) 1.25, where the distance is measured in centimetres, or (ii) 2, where the distance is measured in inches. (3) Every bus, other than a school bus and a prison bus, must be provided with unobstructed openings for rapidly urgent egress, the combined areas of which, when measured (a) in square centimetres, is equal to at least 430 times the number of designated seating positions on the bus; or (b) in square inches, is equal to at least 67 times the number of designated seating positions on the bus. (4) A minimum of 40 per cent of the combined areas of the unobstructed openings required by subsection (3) shall be provided on each side of the bus. (5) In determining the combined areas of unobstructed openings provided in a bus, no emergency exit, regardless of its actual area, shall be deemed to measure more than 3 450 cm 2 (536 square inches). (6) Subject to subsection (7), the unobstructed openings required by subsection (3) shall be provided in every bus with a GVWR of more than 4 536 kg (10,000 lb.) by (a) at least one side door for each three designated seating positions in the vehicle; or (b) side exits and at least one rear emergency exit that meets the requirements of subsections (11) to (14) when the bus is upright and when it is overturned on its side and any occupant is standing facing the rear emergency exit. (7) Where the configuration of a bus described in subsection (6) precludes the installation of an accessible rear emergency exit, the bus shall be equipped in its rear half with a roof emergency exit that meets the requirements of subsections (11) to (14) when the bus is overturned on its side and any occupant is standing facing the roof emergency exit. (8) The unobstructed openings required by subsection (3) shall be provided in every bus with a GVWR of 4 536 kg (10,000 lb.) or less by (a) devices that meet the requirements of subsections (11) to (14) and do not use remote controls or central power systems; (b) windows that can be opened manually to a position providing an opening large enough to admit unobstructed passage of an ellipsoid, with its major axis parallel to the longitudinal axis of the vehicle, that is generated by the rotation about its minor axis of an ellipse having a major axis of 500 mm (20 inches) and a minor axis of 330 mm (13 inches); or (c) doors. (9) Every school bus shall be provided