Can the conspicuity of objects be predicted from laboratory experiments? Effects of age and illumination on night driving: a road test. Highlighting human form and motion information enhances the conspicuity of pedestrians at night. Actual pedestrian visibility and the pedestrian's estimate of his own visibility. Safety clothing for human traffic obstacles. High visibility safety apparel and nighttime conspicuity of pedestrians in work zones. Effects of retroreflector positioning on nighttime recognition of pedestrians. Limitations in drivers' ability to recognize pedestrians at night.
nan This study investigated the effects of drivers' age and low light on speed, lane keeping, and visual recognition of typical roadway stimuli.
                Poor visibility, which is exacerbated by age-related changes in vision, is a leading contributor to fatal nighttime crashes. There is little evidence, however, concerning the extent to which drivers recognize and compensate for their visual limitations at night.
                Young, middle-aged, and elder participants drove on a closed road course in day and night conditions at a "comfortable" speed without speedometer information. During night tests, headlight intensity was varied over a range of 1.5 log units using neutral density filters.
                Average speed and recognition of road signs decreased significantly as functions of increased age and reduced illumination. Recognition of pedestrians at night was significantly enhanced by retroreflective markings of limb joints as compared with markings of the torso, and this benefit was greater for middle-aged and elder drivers. Lane keeping showed nonlinear effects of lighting, which interacted with task conditions and drivers' lateral bias, indicating that older drivers drove more cautiously in low light.
                Consistent with the hypothesis that drivers misjudge their visual abilities at night, participants of all age groups failed to compensate fully for diminished visual recognition abilities in low light, although older drivers behaved more cautiously than the younger groups.
                These findings highlight the importance of educating all road users about the limitations of night vision and provide new evidence that retroreflective markings of the limbs can be of great benefit to pedestrians' safety at night. Exploring how biological motion can make pedestrians more conspicuous to drivers at night, one-hundred-and-twenty participants were driven along an open-road route at night and pressed a button whenever they recognized that a pedestrian was present. A test pedestrian wearing black clothing alone or with 302 cm2 of retroreflective markings in one of four configurations either stood still or walked in place on an unilluminated sidewalk. Participants' response distances were maximal for the full biological-motion configuration and remained surprisingly long when convenient subsets of reflective markers were positioned on the pedestrian's ankles and wrists. When the pedestrian wore a reflective vest, the responses were no better than when he wore no reflective markings. The biological-motion advantage actually results from interacting form-perception and motion-perception mechanisms. These results confirm that basic perceptual phenomena-observers' sensitivity to human form and motion can be harnessed to reduce an important problem of traffic safety. nan nan Every year numerous occupational fatalities result from pedestrians being struck by motor vehicles intruding into work zones.
                Attributes of retroreflective personal safety garments on pedestrian conspicuity at night were assessed in a field study. Using instrumented vehicles on a closed track, participants drove through simulated work zones attempting to detect pedestrians located in the work zones.
                Configuration of the retroreflective trim, trim color, placement in the work zone, and driver age significantly affected pedestrian conspicuity. Intensity and the amount of retroreflective trim did not.
                Personal safety garments incorporating retroreflective trim significantly improve pedestrian conspicuity in work zones.
                The results emphasize the importance of retroreflective trim on personal safety garments, particularly if the trim is located on garment sleeves.
                We examine the design attributes that contribute to making a personal safety garment conspicuous. The results have implications regarding preferred garment designs, industry standards, and service life of personal safety garments. This field study investigated 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 results showed that each retroreflector configuration yielded significantly longer recognition distances than the no-retroreflector configuration. More importantly, the retroreflective markings attached to the limbs led to significantly longer (about 60-80%) recognition distances than when the retroreflective markings were attached to the torso. Furthermore, a pedestrian was more recognizable while crossing the road than while approaching the subject vehicle, except for configurations involving no retroreflective markings. This study quantified drivers' ability to recognize pedestrians at night. Ten young and 10 older participants drove around a closed road circuit and responded when they first recognized a pedestrian. Four pedestrian clothing and two beam conditions were tested. Results demonstrate that driver age, clothing configuration, headlamp beam, and glare all significantly affect performance. Drivers recognized only 5% of pedestrians in the most challenging condition (low beams, black clothing, glare), whereas drivers recognized 100% of the pedestrians who wore retroreflective clothing configured to depict biological motion (no glare). In the absence of glare, mean recognition distances varied from 0.0 m (older drivers, low beam, black clothing) to 220 m (722 feet; younger drivers, high beam, retroreflective biomotion). These data provide new motivation to minimize interactions between vehicular and pedestrian traffic at night and suggest garment designs to maximize pedestrian conspicuity when these interactions are unavoidable.
Visibility aids have the potential to increase visibility and enable drivers to detect pedestrians and cyclists earlier. Biomotion markings, which highlight the movement and form of the pedestrian, showed evidence of improving pedestrians' conspicuity at night. Public acceptability of various effective strategies which improve visibility would merit further development. However, the effect of visibility aids on pedestrian and cyclist safety remains unknown. A cluster randomised controlled trial involving large communities may provide an answer to this question. It would, however, be a challenging trial to conduct. Studies that collect data of road traffic injuries relating to the use of visibility aids also warrant consideration.