Abstract: In order to reduce human-vehicle conflicts triggered by unsafe behaviors, evolution mechanism of human-vehicle interaction behaviors were analyzed from perspective of optimistic bias, and a human-environment-risk relationship model based on perceptual reasoning was proposed. On this basis, three groups of interaction experiments with different risk scenarios were designed. The results show that decline in risk exposure will stimulate optimistic bias, which will lead to unsafe behaviors, and such exposure shows a negative correlation with hidden risks. And risks with higher exposure are more likely to trigger unsafe behaviors when exposure level decreases. Effective rules to restrain behaviors can increase psychological cost of violations, and the major ways to reduce unsafe behaviors of pedestrian are optimizing environmental design and blocking spread of halo effects.

Key words: optimistic bias, unsafe behaviors, risk exposure level, perception reasoning, environmental information