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 then only after giving a clearly audible signal by sounding the horn if any pedestrian may be affected by such movement or after giving an appropriate signal in the manner provided in sections 321.315 through 321.318 in the event any other vehicle may be affected by such movement.
Iowa Code § 321.314
2021 Acts, ch 80, § 171
Referred to in §321.316, 805.8A(6)(n)
For applicable scheduled fine, see §805.8A, subsection 6