§ 1237. Method of giving hand and arm signals by bicyclists. All signals herein required to be given by bicyclists by hand and arm shall be given in the following manner and such signals shall indicate as follows:

1. Left turn. Left hand and arm extended horizontally.

2. Right turn. Left hand and arm extended upward or right hand and arm extended horizontally.

3. Stop or decrease speed. Left hand and arm extended downward.