RCW 46.61.780 Lamps and other equipment on bicycles
Every bicycle when used during the hours of darkness as defined in RCW 46.37.020 shall be equipped with a lamp on the front which shall emit a white light visible from a distance of at least five hundred feet to the front and with a red reflector on the rear of a type approved by the state commission on equipment which shall be visible from all distances from one hundred feet to six hundred feet to the rear when directly in front of lawful lower beams of head lamps on a motor vehicle. A lamp emitting a red light visible from a distance of five hundred feet to the rear may be used in addition to the red reflector.
Every bicycle shall be equipped with a brake which will enable the operator to make the braked wheel skid on dry, level, clean pavement.