§ 71.08 SIGNALS.
   (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 only after a clearly audible signal has been given by sounding the horn if any pedestrian shall be affected by the movement. No person shall so turn any vehicle without 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 the intention to turn right or left shall be given continuously for not less than the last 100 feet traveled by the vehicle before turning.
   (C)   No person shall stop or suddenly decrease the speed of a vehicle without first giving an appropriate signal in the manner provided herein to the operator of any vehicle immediately in the rear when there is opportunity to give such signal.
   (D)   All signals required herein shall be given either by means of the hand and arm or by a signal-lamp or lamps or a mechanical signal device, except that the operator of a motor vehicle used for the transportation of persons for hire with taxicabs excluded, the operator of a school or church bus, and the operator of any vehicle so constructed or loaded that a hand and arm signal would not be visible both to the front and rear of such vehicle shall indicate an intention to turn by use of a signal lamp or lamps or mechanical signal device and must indicate an intention to stop or suddenly decrease speed by illuminating at least one red or yellow light with the word “Stop” on it on the rear of the vehicle.
   (E)   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:
      (1)   Left turn: hand and arm extended horizontally;
      (2)   Right turn: hand and arm extended upward; and
      (3)   Stop or decrease speed: hand and arm extended downward.
(1980 Code, § 520.3-9) Penalty, see § 70.99