In the frame of the European research project VEDILIS (VEhicle DIscharge LIghting System) the influence of the size of D1 headlamps on the discomfort glare was examined in the laboratory. The discomfort was subjectively assessed with the nine-point rating scale of "De Boer". The glare sources were rectangular with areas ranging from 0.00059 to 0.151 square degrees. The glare angles varied from 1.72 to 6.84 degrees. The glare illuminance at the observer's eye, varied from 0.03 to 3 lux. In addition to the expected effects of the glare illuminance and the glare angle on the discomfort rating, a small but significant effect of the size of the glare source was found. A glare source which is a factor two smaller in size (factor four in area) increases the discomfort glare with 0.1 points. This increase can be compensated by a decrease of the light intensity of the lamp by 11%. No effect of age and sex on the discomfort glare was found. However, a correlation between age and disability glare was found.
Samenvatting