The effects of speed and orientation on recognition judgments of retro-reflectively clothed pedestrians at night.

Background Insufficient conspicuity of pedestrians at night is a fundamental contributor to injuries and fatalities. Retro-reflective clothing that enhances biological motion perception increases detection and identification of pedestrians at night. Objective To determine how speed of motion and body orientation affect observers’ judgments about the recognisability of pedestrians with bio-motion retro-reflectors. Method The stimuli used in this study were videos of a retro-reflectively outfitted pedestrian on a treadmill filmed in a nighttime road environment. Forty undergraduate students observed videos of pedestrians who were standing, walking or running with the side or back of their body oriented towards the observer. Participants decided which of the two pedestrians was most recognizable as a person. Judgments were made in high beams and low beams at 80 m, 160 m and 240 m. Results For both orientations, observers judged that walking and running pedestrians were more recognizable than standing pedestrians. Observers also judged that running pedestrians were more recognizable than walkers. The effect of pedestrian orientation was dependent on speed. When standing, pedestrians in the back orientation were selected more often, but when running, side-oriented pedestrians were selected as the most recognizable. Conclusions Speed of motion and body orientation affect observers’ judgments of the recognisability of pedestrians wearing retro-reflectors at night. Observers choose moving pedestrians (i.e., those who are walking or running) in biomo retro-reflectors as more recognizable as people than pedestrians who stand. The results fill several gaps in the literature and have practical and future research implications, which are discussed. [ABSTRACT FROM AUTHOR]