The Effect of CCT Tunable LED Headlamp on Target Visibility of Vehicles and Road Surfaces under Adverse Weather Condition

A quantitative measurement was conducted to find out the effect of CCT tunable LED headlamp on the targets of vehicle and road surface under artificial weather environment. For this, a CCT tunable headlamp with different CCT from 3500K to 6500K and diverse targets like vehicle reflectors, a license plate, and lanes were used. Experimental weather conditions consisted of clear, light fog, heavy fog, light rain, and heavy rain. We measured the luminance of the targets and backgrounds, and then calculated the contrast ratio based on their luminance. The result showed that the low CCT headlamp was better for the visibility of the targets on vehicle and road surface, particularly in reflectors, than the high CCT headlamp. We discussed the influence of target visibility by CCT tunable headlamps and their applicability to vehicles in adverse weather conditions.