Iowa law requires that drivers use their turn signal under certain circumstances. Those requirements are specified in Iowa Code Sections 321.314 and 321.315:
As can be seen from code sections shown below and Iowa case law, the duty to signal a turn in Iowa is not as strong as the duty in many other states. Indeed, not signaling in Iowa is lawful under certain circumstances that would constitute a traffic offense in many other states. However, it is always wise to signal turns and lane changes in Iowa so as to minimize the risk of a car accident.
Iowa Code 321.314 – When signal required
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 hereinafter provided in the event any other vehicle may be affected by such movement.
Iowa Code 321.315 – Signal continuous
A signal of intention to turn right or left shall be given continuously during not less than the last one hundred feet traveled by the vehicle before turning when the speed limit is forty-five miles per hour or less and a continuous signal during not less than the last three hundred feet when the speed limit is in excess of forty-five miles per hour.