Development and Evaluation of a Photoluminescent–Reflective Cat’s Eye Road Stud for Tropical Urban Road Safety

This study presents the development and evaluation of a photoluminescent–reflective cat’s eye road stud designed to enhance nighttime visibility and road safety in tropical urban environments, with particular emphasis on road conditions in the Philippines. The proposed road stud integrates a passive photoluminescent layer with conventional retroreflective elements within a sealed, dome-shaped structural housing, enabling continuous visibility under both illuminated and non-illuminated conditions without external power requirements. A developmental–experimental research design was employed, encompassing material selection, prototype fabrication, and optical performance evaluation under dry and wet surface conditions. Experimental results demonstrate sustained photoluminescent afterglow exceeding six hours following light excitation, ensuring visibility during periods of limited or absent street lighting. Under vehicle headlight illumination, the retroreflective components provided immediate visibility comparable to conventional reflective studs, confirming that hybrid integration does not compromise reflective performance. Wet-condition testing further revealed that the dome geometry and self-emissive capability effectively mitigate visibility degradation caused by rainfall and surface water films—conditions commonly encountered on Philippine urban roads. Overall, the findings indicate that the proposed photoluminescent–reflective road stud offers enhanced all-condition visibility, environmental resilience, and low-maintenance operation compared to conventional reflective markers. The developed system provides a practical, energy-independent, and scalable solution for improving nighttime road delineation and safety in tropical developing regions.