Form and colour of studs
7.—(1) The studs shown in the diagrams in this Schedule shall be—
(a)coloured white, silver or light grey and shall not be fitted with reflective lenses; and
(b)either circular in shape with a diameter of not less than 95 mm nor more than 110 mm or square in shape with the length of each side being not less than 95 mm nor more than 110 mm.
(2) Any stud which is fixed or embedded in the carriageway shall not project more than 20 mm above the carriageway at its highest point nor more than 6 mm at its edges.