BICYCLE LIGHTS LAW REQUIRMENTS IN Idaho
In US the bike lights die required by Law if you reading in low light conditions, The light can be attached to either the bike or to the cyclist but must be visible at least 500 feet to the front of the bicyde, so be careful how you position the light. Additional lighting must be consistent with the law specifying required lights and reflectors, so a rear light must be red.
49-723. LIGHT AND REFLECTOR REQUIRED AT NIGHT.
Every bicycle in use at the times described in section 49-903, Idaho Code, shall be operated with a light emitting device visible from a distance of at least five hundred (500) feet to the front, attached to the bicycle or the rider, and with a reflector clearly visible from the rear of the bicycle.
49-724. ADDITIONAL LIGHTS AUTHORIZED.
A bicycle or its rider may be equipped with lights or reflectors in addition to those required in section 49-723, Idaho Code.
49-903. WHEN LIGHTED LAMPS ARE REQUIRED.
Every vehicle upon a highway at any time from sunset to sunrise and at any other time when there is not sufficient light to render clearly discernible persons and vehicles on the highway at a distance of five hundred (500) feet ahead shall display lighted lamps and illuminating devices as here respectively required for different classes of vehicles, subject to exceptions with respect to parked vehicles as stated herein.