Section 39-21-11 - Visibility of reflectors, clearance lamps, and marker lamps1. Every reflector upon any vehicle referred to in section 39-21-08 must be of such size and characteristics and so maintained as to be readily visible at nighttime from all distances within six hundred feet [182.88 meters] to one hundred feet [30.48 meters] from the vehicle when directly in front of lawful lower beams of headlamps, except that the visibility for reflectors on vehicles manufactured or assembled prior to January 1, 1970, must be measured in front of lawful upper beams of headlamps. Reflectors required to be mounted on the sides of the vehicle must reflect the required color of light to the sides, and those mounted on the rear must reflect a red color to the rear.2. Front and rear clearance lamps must be capable of being seen and distinguished under normal atmospheric conditions at the times lights are required at a distance of five hundred feet [152.4 meters] from the front and rear, respectively, of the vehicle.3. Side marker lamps must be capable of being seen and distinguished under normal atmospheric conditions at the times lights are required at a distance of five hundred feet [152.4 meters] from the side of the vehicle on which mounted.