TEST METHOD FOR DETERMINING THE EXPOSED SURFACE AND EFFECTIVE SURFACE OF THE MIRRORS LOCATED AT THE FRONT OF THE BUS
The following are the steps to be used for the test method:
(1) As illustrated in Figure A, place cylinders 30 cm in diameter and 30 cm in front of the bus and along its sides in the following positions:
— 3 cylinders placed tangentially to the transversal plane, along the foremost part of the front bumper; one of those cylinders shall be placed at either end of the bumper and one in the middle;
— one cylinder placed in front of the bus, along the projection of its longitudinal axis, at the shorter of the following distances from the bus:
— the distance at which the upper end of the cylinder starts to be directly visible to the driver when his eyes are positioned 68.6 cm above the meeting point of the seat back and the seat cushion, with the seat in the middle position at which it can be adjusted sliding backwards and forwards and in its lowest position; or
— the distance at which the centre of the cylinder is 3.65 m from the bumper;
— 4 cylinders placed 30 cm from the vertical projection of the side wall of the bus, directly facing the centre of the front and rear wheels; and
— 2 cylinders placed 1.83 m from the vertical projection of the side wall of the bus, directly facing the centre of the rear wheel.
(2) Draw lines delimiting the following testing areas, as illustrated in Figure A:
— the ground area within a 2-m perimeter of the bus;
— the ground area in front of the bus, extending beyond the 2-m perimeter but lying within lines delimiting a 7-m extension of the side walls of the bus; and
— the side walls and front of the bus to a height of less than 1.5 m.
(3) Adjust the mirrors in such a manner as to limit the area reflected as much as possible to the testing areas while ensuring that the upper end of the cylinders is fully visible. Each mirror must reflect the front cylinders and the cylinders placed along the same side as the mirror.
(4) Take a photograph of the mirrors as seen by the driver. The photograph must include the calibrated distance marks on each mirror.
(5) Using a calibrated grid placed on the photograph, measure the exposed surface of the mirror, which must be greater than 250 cm2.
(6) Using the grid referred to in point 5, measure the surface of the mirror that reflects the testing areas. That surface must correspond to at least 65% of the exposed surface.
METHOD FOR DETERMINING
THE EXPOSED SURFACE AND AND EFFECTIVE SURFACE
direct limit of vision