Effects of Retroreflector Placement on the Nighttime Conspicuity of Pedestrians: An Open-Road Study

Abstract

While considerable data indicate that positioning retroreflective markings on a pedestrian's extremities can dramatically enhance nighttime conspicuity, most relevant safety devices (vests) limit coverage to the torso. We asked 120 participants to press a button whenever they recognized that a pedestrian was present during a short drive at night. A test pedestrian wearing different configurations of retroreflective markings was positioned on the left shoulder of an unilluminated two-lane roadway. Compared to an ANSI class-II vest alone, response distances were significantly greater when the vest was supplemented with ankle markings and when a full biological motion configuration was worn. Conspicuity was also greater when the pedestrian was walking and when facing the approaching test vehicle. Relative to a full eleven-element biological motion configuration, adding just two retroreflective ankle straps to a conventional safety vest is considerably more practical while still providing substantial conspicuity benefits.