Impacts of LED Brightness, Flash Pattern, and Location for Illuminated Pedestrian Traffic Control Device

Illuminated traffic control devices, such as rectangular rapid-flashing beacons (RRFB), have been shown to increase the number of drivers yielding to crossing pedestrians. There is some concern that the brightness of flashes at or contained within signs at night may make it difficult for drivers to detect and observe the movements of pedestrians at the crossing. To prevent devices from being set at brightness levels that produce disability or discomfort glare, the profession needs to quantify the effect of illuminated traffic control devices on a driver’s ability to detect pedestrians in and around the crosswalk. This TechBrief describes the methodology and results from a closed-course study sponsored by the Federal Highway Administration (FHWA) that addressed brightness, flash patterns, and location of light-emitting diodes (LED). It examined driver detection of cutout pedestrian photographs in the presence of LEDs of various brightness levels and flash patterns, which are placed in different locations within the sign assembly.