University of Kansas
About the research
The three models of self-illuminating vests were compared to a standard KDOT safety vest and a low-end off the shelf vest with respect to their nighttime visibility. The vests were mounted at an appropriate height for an average size worker, and a test vehicle was specially equipped to all accurate measurement of the orientation of the headlights relative to the vests. A digital video camera was used to record the vests from the drivers perspective at several vehicle orientations and distances, using both high beams, low beams, and without headlights. Custom software was developed to calculate visibility indices for each of the vests for each of the observed conditions. It was found that when the headlights were oriented directly at the vests, the self-illumination had little, if any, effect. Reflected light drowned out the self-illuminations. At eccentricities of 10 degrees, more than 20% of the vest brightness was due to the self illumination, and at eccentricities greater than 30 degrees, nearly all of the vest brightness was self-generated. The self-illuminating vests were more visible than the purely reflective vests under all conditions. In addition to the greater brightness, the blinking of the LEDs would presumably increase the vest conspicuity over a simply reflective vest, although this test did not measure conspicuity per se. The batter life was tested, and battery replacement costs would be negligible. The vests themselves are durable, but some care should be observed in storage not to damage the wires connecting the LEDs to the battery pack. The weight of the batteries was noticeable, but not egregious.
Vendor: Illumination Polymer Tech.