“四一”特大交通事故中，横卧于机动车道内的条石是导致此事故的重要原因。 根据现场勘查，４月１日晚有零星小雨，路面湿，无路灯照明，潮湿的路面和条石在夜间颜色反差不大。因此，客观上路右侧的条石不易被司机察觉；加之雨天，戴头盔的骑车人视线较为模糊，未戴头盔的骑车 In the “41” accident, strakes lying in motor vehicle lanes are the major causes of this accident. According to the site survey, the evening of April 1 sporadic light rain, wet road, no street lighting, wet pavement and stone in the night color contrast is not big. Therefore, it is not easy for drivers to perceive the stakes on the right side of the road objectively. In addition, on rainy days, cyclists wearing helmets have a rather blurred vision and helmet-free bicycles