Resistance of LED and incandescent front turn signals to masking effects from adjacent headlamps

Abstract

Previous research has shown that, as expected, fast-rise signals (such as LEDs and neon lamps) lead to shorter reaction time than slower-rise signals (such as incandescent lamps). The present study, in two converging experiments, investigated whether rapid rise time makes turn signals more resistant to masking from an adjacent headlamp. The first experiment used a method of limits to obtain luminous intensity thresholds for LED and incandescent turn signals in the presence of headlamp glare. In the second experiment, subjects judged the relative conspicuity of simultaneously presented LED and incandescent turn signals when they flanked an illuminated headlamp. The results of the two experiments were consistent: There was no difference between the two light sources in either detection threshold or judged conspicuity. These results suggest that faster rise time does not affect the resistance of turn signals to headlamp masking.