All signals given by hand and arm shall be given by hand and arm extended beyond the left side of the vehicle in the following manner, and shall indicate the turns that follow:

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.

4.  Reentering lane of traffic from parked position: Hand and arm extended horizontally.