The effects of retroreflective materials on recognition of pedestrian were investigated by a felid experiment conducted at night. And whether attachment of retroreflective materials influences the risk of being involved in pedestrian accidents was examined by analyzing traffic accident data and survey data concerning the diffusion of retroreflective materials. The results showed that when pedestrians wore retroreflective materials the recognition distances were longer, pedestrians tend not to be overlooked by drivers and the risk to be crashed was lower even if a pedestrian dashed out in front of a car by mistake. Further, the analysis of accident data and survey data revealed that the risk of involvement in accidents was extremely lower for pedestrians wearing retroreflective materials than that for pedestrians not wearing retroreflective materials.