Abstract: In order to study the influence of environmental factors on the perception of tripping risks, this research is performed on the factors including lighting conditions, walkway, obstacle types, obstacle colors and heights. Experiments were made on the following cases: light and dimmed conditions, two kinds of walkways, two types of obstacles, namely plates and rods, two different colors (black and white) and five different heights. The rating of RRT was given by the subjects both before and after walking, and the rating of gait disturbance (RD) and the time of walking were recorded by the experimenter. The results show that the lighting condition, obstacle types, obstacle colors and heights all exert significant effects on both RRT and RD, and the color contrast also affects RRT significantly. The probability of contacting an obstacle under the dimmed condition is 15 times that under the normal lighting condition.

Key words: subjective feeling, rating of risk of tripping(RRT), gait disturbance, obstacles, environmental factors