(a) The crossing sign shall be a rigid disk 18 inches in diameter and brilliant red in color. The word STOP in 6 inch white letters shall appear in the center of the disk. The word SCHOOL shall appear in 2-inch white letters directly above and parallel to the word STOP, and the word CROSSING shall appear in 2-inch white letters directly below and parallel to the word STOP.
(b) The sign shall be fastened to a round pole approximately six feet in length, and at such an angle that when the sign is extended in an operating position the lettering will be horizontal.
(c) In lieu of the crossing sign referred to in subsections (a) and (b) of this section, any other type of crossing sign approved by the Department of Public Works may be used.