(a) No person shall turn a vehicle from a direct course upon a highway unless and until the movement can be made with reasonable safety and then only after giving a clearly audible signal by sounding the horn if any pedestrian may be affected by the movement or after giving an appropriate signal in the manner provided in subsection (b) of this section in the event any other vehicle may be affected by the movement.
(b) A signal of intention to change lanes or to turn right or left shall be given continuously during not less than the last one hundred feet (100') traveled by the vehicle before changing lanes or turning.
(c) No person shall stop or suddenly decrease the speed of a vehicle without first giving an appropriate signal in the manner provided in this subchapter to the driver of any vehicle immediately to the rear when there is opportunity to give such signal.