Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



Committee Member

Dr. Richard A. Tyrrell, Committee Chair

Committee Member

Dr. David M. Neyens

Committee Member

Dr. Patrick J. Rosopa

Committee Member

Dr. Benjamin R. Stephens


Recent literature indicates that active lighting, when strategically positioned, improves bicyclists' conspicuity at night. Road cyclists are unique among other vulnerable road users in two ways: 1) they can leverage their own biological human motion and mechanical bicycle motion when using conspicuity solutions; 2) their visual surface area shown to approaching traffic is greater when viewed from a right angle (i.e., 90 degrees) than from the front/rear. However, research has not yet identified how to utilize these factors to maximize conspicuity. This project investigated the conspicuity benefits of using various configurations of six LEDs on a cyclist's body and bicycle. Experiment 1 quantified participants' responses to video recordings of a nighttime drive that featured a test bicyclist. Experiment 2, a nighttime study on a closed road, quantified participants' subjective ratings of bicyclist conspicuity at night. The findings from these studies confirmed that capitalizing on drivers' sensitivity to patterns of motion can significantly enhance bicyclists' nighttime conspicuity when viewed from the side. Particularly effective is highlighting the rotating motion of a bicycle's wheels, allowing drivers to quickly and easily identify bicyclists.



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