Abstract: A road safety system includes: a plurality of road markers installed on a road, and configured to generate humidity data by measuring air humidity and generate temperature data by measuring air temperature; and a server configured to receive the humidity data and the temperature data from each of the plurality of road markers, generate fog occurrence information indicating that an atmospheric state around the road satisfies a fog occurrence condition on the basis of the humidity data and the temperature data, and generate icing occurrence information indicating that a surface of the road satisfies an icing occurrence condition on the basis of the humidity data and the temperature data, wherein each of the plurality of road markers outputs fog alert light when the fog occurrence information is received from the server and outputs icing alert light when the icing occurrence information is received from the server.