Sec. 9. A stop sign that is installed after July 1, 1990, to control the movement of vehicular traffic in an area subject to this chapter must meet the following requirements:
(1) The face of the sign must have a red background with white letters and a white border.
(2) The sign must be an octagon.
(3) The sign must measure at least twenty-four (24) inches wide and twenty-four (24) inches high.