Washington Revised Code Title 46. Motor Vehicles § 46.37.060. Reflectors

(1) Every motor vehicle, trailer, semitrailer, and pole trailer shall carry on the rear, either as a part of the tail lamps or separately, two or more red reflectors meeting the requirements of this section: PROVIDED, HOWEVER, That vehicles of the types mentioned in RCW 46.37.090 shall be equipped with reflectors meeting the requirements of RCW 46.37.110 and 46.37.120.

(2) Every such reflector shall be mounted on the vehicle at a height not less than fifteen inches nor more than seventy-two inches measured as set forth in RCW 46.37.030(2), and shall be of such size and characteristics and so mounted as to be visible at night from all distances within six hundred feet to one hundred feet from such vehicle when directly in front of lawful upper beams of head lamps, except that reflectors on vehicles manufactured or assembled prior to January 1, 1970, shall be visible at night from all distances within three hundred and fifty feet to one hundred feet when directly in front of lawful upper beams of head lamps.