Evaluation of Visual Performance Using LED Signboards under Different Ambient Conditions

Assessment of drivers' visual perception of information displayed in LED traffic signs at road construction sites

“…As for the arrow style, the result of the experiment shows that the glare distance changes depending on the style of the arrow. The arrow “<<<” has a greater glare distance than the arrow “←” because the arrow “<<<” has more display light points than the arrow “←.” As for the luminance ratio, previous studies note that an increase in the background brightness can reduce the uncomfortable glare. The glare distance when the sign brightness is 6200 cd/m 2 and the background brightness is 2066 cd/m 2 is greater than the glare distance when the sign brightness is 6200 cd/m 2 and the background brightness is 0 cd/m 2 because, with the sign brightness of 6200 cd/m 2 unchanged, the glare level increases due to the background brightness at the distance at which the driver perceives the glare.…”

“…Other studies have explained that the distance of signs which can be seen by human vision can be increased by augmenting the background luminance to enable the signs and their background to reach a favorable ratio . In general, the recommended luminance contrast is 3:1 . Therefore, in this study, the LED traffic signs designed featured both adjustable display brightness and background luminance to elevate drivers' visual perception.…”

“…11 In general, the recommended luminance contrast is 3:1. 12,13 Therefore, in this study, the LED traffic signs designed featured both adjustable display brightness and background luminance to elevate drivers' visual perception.…”

“…Studies have shown that the effects of drivers' recognition performance, 14 vehicle speed, 15 and headlamp glare 16 differ under different levels of environmental luminance 17 ; such factors influence drivers' visual perception. Wu et al 13 investigated the extent of the glare of LED displays at environmental luminances of 30,000; 5000; and 10 lx and found that the visual acuity and glare response changed under high luminance (30,000 lx). 13 Literature data have shown that Taiwan's environmental luminance reaches 50,000 lx on extremely bright days.…”

“…Wu et al 13 investigated the extent of the glare of LED displays at environmental luminances of 30,000; 5000; and 10 lx and found that the visual acuity and glare response changed under high luminance (30,000 lx). 13 Literature data have shown that Taiwan's environmental luminance reaches 50,000 lx on extremely bright days. 18 In this study, the effect of 50,000 lx of environmental luminance on drivers' visual perception was explored.…”