Compliance Testing for Locomotive LED Headlights and Auxiliary Lights, Phase II
With the development of new lighting technologies, such as light-emitting diodes (LED), the safety requirements stipulated in 49 CFR §229.125 may not adequately accommodate the introduction of LED lamps to the railroad industry. Consequently, it is necessary to better understand the current state of LED technology with respect to such safety requirements. The purpose of Phase II was to evaluate visibility and glare aspects of human-sized objects in lighting conditions produced by different lamps in a stationary locomotive. Visibility aspects were evaluated via contrast discrimination. Results showed that LED lamps provide better contrast discrimination than halogen lamps along the tracks, but worse contrast discrimination than halogen lamps at an angle offset of 7.5° from the centerline of the locomotive. Discomfort glare was evaluated using the De Boer scale. For glare rating in bright mode, results showed no statistically significant differences between LED and halogen lamps. However, for glare ratings made in dim mode, statistically significant differences between both headlamp types were found, with LED lamps producing worse glare ratings than halogen lamps.