Road Weather Information System in Finland

Abstract

Weather has a significant impact on winter traffic, directly by causing poor visibility or indirectly by causing poor driving conditions (e.g., slipperiness due to snow, slush, or ice on the road), multiplying the risk of an accident. To decrease accident risk and to improve safety and traffic flow, the Finnish National Road Administration has developed a road weather information system (RWIS), the purpose of which is to provide the road maintenance staff with information about prevailing road and weather conditions on the road network in winter. With the help of this system, road maintenance measures such as salting and plowing can be timed better, and the amount of antislipping agents used can be optimized to a minimum level. Another growing function of the system is to provide information to road users. The system’s operation is based on automated road weather stations equipped with measuring devices. Approximately 270 road weather stations located along the main roads throughout the entire country are currently connected to the system. These stations collect data about air, road surface, and dew point temperatures; wind; humidity; rain; visibility; and surface road conditions. The RWIS retrieves data from the road weather stations every 15 to 60 min. All road weather data are centrally stored in a common, national database. The current status of the Finnish RWIS is described, and plans for the future are discussed.