The driver of any vehicle upon a highway before starting, stopping, or turning from a direct line shall first see that such movement can be made in safety and if any pedestrian may be affected by such movement shall give a clearly audible signal by sounding the horn, and whenever the operation of any other vehicle may be affected by such movement shall give a signal as required in § 71.075 plainly visible to the driver of such other vehicle of the intention to make such movement.
(SDCL § 32-26-22) Penalty, see § 70.99