The signal required in § 71.074 shall be given either by means of the hand and arm in the manner specified in § 71.076, or by an approved mechanical or electrical signal device. However, a vehicle is so constructed or loaded as to prevent the hand and arm signal from being visible both to the front and rear, the signal shall be given by device of a type which has been approved by the Department of Public Safety.
(SDCL § 32-26-23) Penalty, see § 70.99