%A A. Bierman %A P. Boyce %A C. Hunter %A J. Bullough %A M. Figueiro %A K. Conway %T The Effect of Rise Time on the Detection of Traffic Signals %X The rise time of a light source is the time it takes to reach full light output after application of power. Different light sources used in traffic signals have different minimum rise times. LEDs have minimum rise times in the order of nanoseconds, while incandescent lamps have minimum rise times in the order of tens of milliseconds. Whether these rise times are achieved in practice depends on the characteristics of the power supply applied to the light source. Measurements of the rise times of actual traffic signals showed that LED traffic signals had rise times of approximately 20 ms while incandescent traffic signals had a range of rise times from 90 ms to 200 ms. This study was undertaken to determine if such dfferences in rise times influence detection of the traffic signal, measured by the reaction time to onset of the traffic signal and percentage of missed signals. %D 2000 %K light emitting diodes, visibility, reaction times %I Rensselaer Polytechnic Institute %L cogprints3852