Snow fall and icing on traffic roads in the winter season cause not only inconvenience but unexpected traffic accidents, so the proper measures are needed. The existing road information system is being installed for steep slope roads in mountain areas, however, it is not widely adopted because it is too expensive. In this paper, a novel and cost-effective road weather information system especially for snow fall and icing on roads is proposed. The system consists of digital temperature and relative humidity sensor, infrared temperature sensor, ultrasonic sensor, CMOS camera, and two types of control/communication board for ubiquitous sensor network to send the data to server. The server program including the decision making method with received data is also described. Experimental results are provided to prove the feasibility of the proposed system.