Performance investigation of different headlights used in vehicles under foggy conditions.

In this study, an experimental study based on the target visibility criteria is carried out for dark and foggy environments, where only vehicle headlights are active. More specifically, the performances of the headlights containing halogen, xenon, and LED light sources in dark and foggy weather conditions are examined and the performance of each headlight is evaluated separately. According to the general result of the visibility experiments, the participants perceived the target object in a shorter time when halogen headlights are used. It is also observed that the average target perceived times of the participant under foggy conditions are at different levels depending on the type of headlights with different correlated color temperature (CCT) and color rendering (CRI) indexes. According to the experimental results performed under foggy conditions, the target detection times of the participants are the shortest at the halogen headlight, the second at the xenon headlight, and the third under the LED lights. It has also been observed that this sequencing is gender-independent. However, the ratio of the detection time of female participants to that of male participants varies between 1.72 and 3.65 times. In other words, female participants perceive the targets in a much longer period than male participants.