No driver of a vehicle shall suddenly start, slow down, stop or attempt to turn without first giving a suitable signal in such a manner as to surprise others who might be affected by his action.
(A) No person shall turn a vehicle from a direct course upon a highway unless and until such 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 such movement or after giving an appropriate signal in the manner hereinafter provided in the event any other vehicle may be affected by such movement.
(B) A signal of intention to turn right or left shall be given during not less than the last one hundred feet (100') traveled by the vehicle before turning.
The signals herein required shall be given either by means of the hand and arm or by a signal lamp or signal device, but when a vehicle is so constructed or loaded that a hand and arm signal would not be visible both to the front and rear of such vehicle, then said signals must be given by such a lamp or device.
All signals herein required 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:
Left turn--Hand and arm extended horizontally.
Right turn--Hand and arm extended upward.
Stop or decrease of speed--Hand and arm extended downward. (M.C. 1962, sec. 18.304)