Drivers' detection distances to pedestrians and obstacles on the road are too short in car meeting situations on low beam. The purpose of this study was to investigate whether low beam illumination supplemented by UV headlights could give long and safe detection distances. The detection distances were measured in a full scale simulated opposing situation between two vehicles on a straight level two-lane road closed to traffic. The opposing car was stationary in the lane for opposing traffic. The subject's car was driven in the driving lane towards the stationary car. The task of the subjects, as well as the driver, was to detect obstacles to the right in the driving lane. Upon detection, they were immediately to push a silent hand-held switch. The obstacles were flat plates in the form of a square with a side of 0.4 meter. They were covered with cloth and had three reflectances: black, light grey and white. The result showed a non-detectable or minor increase in the detection distances for the black and the light grey targets. However, the detection distances for the white targets were twice as long when the ordinary low beam illumination was supplemented by UV radiation. The relation between the reflectance of clothes and the power to emit visible light in UV radiation was also studied. Measurements showed a relatively strong positive connection and furthermore, the ability to emit visible light in UV radiation increased much more rapidly than the ability to reflect ordinary light when the reflectance of the clothes increased. (A)
Abstract