Abstract
Traffic accidents shortly before and after sunset in Chiba were analyzed. The rate of traffic accidents shortly after sunset was found to be higher than at any other time, whereas the rate shortly before sunset was found to be lower. Traffic accidents caused by sun glare tended not to occur shortly before sunset, because the presence of topographic features meant that the sun had already effectively set. The rate of pedestrian accidents shortly after sunset was higher than that of any other time; the rate shortly before sunset was slightly lower than in day and shortly after sunset, because it was not dark and drivers were not dazzled by sun glare before sunset. However, it is already the case that many vehicle headlights are on shortly after sunset, so it is difficult to decrease pedestrian accidents only by advising drivers to use their lights in the hour before sunset.
