Discomfort Glare Perception by Drivers—Establishing a Link between Subjective and Psychophysiological Assessment

The broad application of LEDs for automotive lighting purposes, together with new discoveries in vision physiology, is creating new challenges in the field of glare perception. The purpose of this study was to link subjective and objective measures of driver-perceived glare following different light sources used in car headlamps. In order to achieve this, a combination of subjective evaluation using an adapted version of the de Boer scale and objective measures based on psychophysiological data was applied. Predominantly, skin conductance response (SCR), heart rate variability (HRV), and eye-blinking frequency (vertical electrooculography, vEOG) were recorded. Though there was some evidence suggesting lower discomfort with glare from light sources with a lower correlated color temperature, the results were generally inconclusive. This illustrates the urgent need to study the linkage between light source properties and subjective and objective glare measures in deeper detail, so that the technical norms governing car headlamps can reflect the needs of human physiology and psychophysiology