(a) Except as provided in subsection (b) hereof, all signals required by this Traffic Code, when given by hand and arm shall be given from the left side of the vehicle in the following manner, and such signals shall indicate as follows:
(1) Left turn: Hand and arm extended horizontally;
(2) Right turn: Hand and arm extended upward;
(3) Stop or decrease speed: Hand and arm extended downward.
(b) As an alternative to subsection (a)(2) hereof, a person operating a bicycle may give a right turn signal by extending the right hand and arm horizontally and to the right side of the bicycle.