01551990

Component

The flash pattern along with the brightness of LEDs, whether used within beacons or embedded in a sign, can help draw drivers’ attention to a device and the area around the device. However, these characteristics can also make it more difficult for drivers to see objects around a device (disability glare) or result in drivers looking away from a device (discomfort glare). This closed-course study investigated how several LED characteristics affect driver’s ability to detect a cutout photograph of a pedestrian within a crosswalk. Brightness intensity was significant for nighttime conditions with detection times increasing by 8.5 percent at 2200 candelas (the maximum used in the study), as compared to when the LEDs were off. Of the six flash patterns tested, only two flash patterns – the 2-5 and the wig-wag – were associated with statistically significantly longer detection times. Both of these patterns have longer on times (the 2-5 is on 69 percent of the cycle and the wig-wag is on 100 percent of the cycle) as compared to the other patterns (range of 10 to 38 percent on time). The findings for pedestrian position and LED location indicate that the distance between the pedestrian and the light source affect the ability to quickly detect the pedestrian. These findings support the idea of placing the LEDs above rather than below the sign.

This paper was sponsored by TRB committee AND40 Visibility.

01550057

15-1443

English

18p

2015

Transportation Research Board 94th Annual Meeting

Digital/other

Photos; References; Tables

Brightness; Crosswalks; Driver performance; Flashing beacons; Glare; Light emitting diodes; Pedestrian safety; Pedestrian vehicle interface; Visibility; Visual perception

Highways; Operations and Traffic Management; Pedestrians and Bicyclists; Safety and Human Factors; I73: Traffic Control

Transportation Research Board Annual Meeting 2015 Paper #15-1443

TRIS, TRB, ATRI

Dec 30 2014 12:33PM