Abstract
In this study, we analyzed the relationship between the nighttime illuminance of road surface and cycling behaviors such as driving speed, sight line angle, avoidance time of on-road obstacle. Based on the street experiments of 30 subjects, we found that the angle of sight line lowered when the road surface illuminance declined from 8.6lx to 3.5lx. In addition, when illuminance was 3.5lx, the obstacle avoidance time was reduced to approximately 0.3 seconds. This means that cyclists are hard to avoid the obstacles. Furthermore, the sight line of subjects who have a high awareness of road obstacle decreases when the road surface illuminance decrease.
