Date of Award


Document Type


Degree Name

Master of Science (MS)



Committee Member

Richard Tyrrell, Committee Chair

Committee Member

Patrick Rosopa

Committee Member

Lee Gugerty


Between 2008 and 2018, pedestrian fatalities have increased 35 percent in the United States and nighttime fatalities are responsible for a substantial portion of this increase. There are two significant problems that limit drivers' ability to respond to pedestrians at night: the degradation of drivers' visual abilities due to low illumination and the low contrast of pedestrians against the background. Pedestrians can make themselves more visible to nighttime drivers by strategically placing retroreflective material on the major joints of the body to highlight their biological motion (biomotion). However, past research on pedestrian conspicuity has largely focused on drivers who are not distracted. Distracted driving is the one of most common causal factor of vehicle crashes and is increasing with advancements in technology. The purpose of this project was to assess the effect of driver distraction on the effectiveness of biomotion to enhance the conspicuity of pedestrians at night. Participants were driven along a predetermined route and asked to respond to all pedestrians they encountered. A test pedestrian was either walking or standing in place while wearing retroreflective biomotion markings. Approximately half of the participants were distracted by a secondary task that demanded cognitive, visual, and manual resources. Although highlighting the pedestrian's biomotion maximized conspicuity, there was no evidence that biomotion mitigated the detrimental effects of distraction. Important limitations with the study, including the possibility that the standing pedestrian was too inconspicuous to allow for a strong test of the hypothesis, are discussed.



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