BICYCLE LIGHTS LAW REQUIRMENTS IN Minnesota
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.
Subd. 6.Bicycle equipment.
(a) No person shall operate a bicycle at nighttime unless the bicycle or its operator is equipped with (1) a lamp which emits a white light visible from a distance of at least 500 feet to the front; and (2) a red reflector of a type approved by the Department of Public Safety which is visible from all distances from 100 feet to 600 feet to the rear when directly in front of lawful lower beams of headlamps on a motor vehicle. A bicycle equipped with lamps that are visible from a distance of at least 500 feet from both the front and the rear is deemed to fully comply with this paragraph.
(b) No person may operate a bicycle at any time when there is not sufficient light to render persons and vehicles on the highway clearly discernible at a distance of 500 feet ahead unless the bicycle or its operator is equipped with reflective surfaces that shall be visible during the hours of darkness from 600 feet when viewed in front of lawful lower beams of headlamps on a motor vehicle. The reflective surfaces shall include reflective materials on each side of each pedal to indicate their presence from the front or the rear and with a minimum of 20 square inches of reflective material on each side of the bicycle or its operator. Any bicycle equipped with side reflectors as required by regulations for new bicycles prescribed by the United States Consumer Product Safety Commission shall be considered to meet the requirements for side reflectorization contained in this subdivision.
(c) A bicycle may be equipped with a front lamp that emits a white flashing signal, or a rear lamp that emits a red flashing signal, or both.