All signals hereon required to be given by hand or arm shall be given from the left side of the vehicle in the following manner and the signals shall indicate as follows:
(A) Left turn. Hand and arm extended horizontally;
(B) Right turn. Hand and arm extended upward; and
(C) Stop or decrease speed. Hand and arm extended downward.
(1980 Code, § 20.305) Penalty, see § 70.99