Idaho Statutes Title 49. Motor Vehicles § 49-808. Turning movements and required signals

(1) No person shall turn a vehicle onto a highway or move a vehicle right or left upon a highway or merge onto or exit from a highway unless and until the movement can be made with reasonable safety nor without giving an appropriate signal.

(2) A signal of intention to turn or move right or left when required shall be given continuously to warn other traffic. On controlled-access highways and before turning from a parked position, the signal shall be given continuously for not less than five (5) seconds and, in all other instances, for not less than the last one hundred (100) feet traveled by the vehicle before turning.

(3) No person shall stop or suddenly decrease the speed of a vehicle without first giving an appropriate signal to the driver of any vehicle immediately to the rear when there is opportunity to give such a signal.

(4) The signals required on vehicles by section 49-809, Idaho Code, shall not be flashed on one (1) side only on a disabled vehicle, flashed as a courtesy or “do pass” signal to operators of other vehicles approaching from the rear, nor be flashed on one (1) side only of a parked vehicle except as may be necessary for compliance with this section.