In every public service vehicle other than a motor cab the tops of the tread of the lowest step for any entrance or exit, other than an emergency exit, shall not be more than 520 millimetres or less than 250 mm above the ground when the vehicle is empty. All steps shall be fitted with non-slip treads. Fixed steps shall not be less than 230 mm inside and shall in no case project laterally beyond the body of the vehicle unless they are so protected by the front wings otherwise that they are not liable to injure pedestrians.
(2) In the case of a double decked vehicle. - (i) the risers of all steps leading from the lower to the upper deck shall be closed and no unguarded aperture shall be left at the top landing ground, (ii) all steps leading from the lower to the upper deck shall be fitted with non-slip treads, (iii) the horizontal distance from the nearest point of the rister of the top step to the vertical line passing through the nearest point of the seat opposite to the top tread of the staircase, excluding any grab rail which does not project more than 75 mm from the back of the seat, shall not be less than 660 mm millimetres, (iv) the outer stringer of an outside staircase shall be so constructed or a band shall be so placed as to screen the persons ascending or descending and the height of the outer guard rail shall not be less than 990 mm above the front of the tread of each step.