This field study was designed to investigate potential effects of retroreflector positioning on recognition of nighttime pedestrians. The subject's task was to press a response button whenever he/she recognized a pedestrian on or alongside the road, while in a car with low-beam lamps on that was driven at a constant speed on a dark road. The recognition distances were determined by the elapsed time between when a subject started a timer and when the vehicle passed the pedestrian. Four retroreflector configurations were tested: (1) no retroreflectors; (2) torso; (3) wrists and ankles; and (4) major joints. Each of these configurations was presented in connection with two walking directions: an approaching and a crossing pedestrian. The subjects did not know the location of targets in advance, and the order of the retroreflector configurations/walking directions was randomized so that the occurence and type of the next target appeared unpredictable to the subjects. The results showed that the mean recognition disntance was 40 m when there were no retroreflectors, 96 m for torso reflectors, 156 m for wrist and ankle reflectors, and 169 m for major points reflectors when a pedestrian was approaching the subject vehicle. When a pedestrian was crossing the road, the corresponding recognition distances were 35, 136, 241, and 249 m, respectively. Each retroreflector configuration yielded significantly longer recognition distances than the no-retrorelfector configuration. More importantly, the retroreflective markings attached to the limbs led to significantly longer recognition distances than when the retroreflective markings were attached to the torso. Furthermore, the effect of walking direction and the interaction between retroreflector configuration and walking direction were significant, indicating that a pedestrian was more recognizable while crossing the road, except for configurations involving no retroreflective markings. The main implication of this study is that retroreflective markings on the limbs, in comparison to those on the torso, significantly increase (by about 60 to 80%) the nighttime recognition distance to pedestrians. (Author/publisher)
Samenvatting