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Frost formation on roads may cause slippery conditions and thereby increase the risk of accident occurrence. Roads are often treated with preventive operations using de-icing agents (e.g. road salt), which are ideally planned and performed prior to frost formation. The decisions on when and where to treat different road stretches with salt are based on meteorological measurements and forecasts. This paper investigates how uncertainties in meteorological measurements for frost prediction at road weather stations affect the efficiency of winter road maintenance. Different types of uncertainties and errors are discussed, together with potential solutions. The effects on winter road maintenance efficiency are discussed in terms of energy and cost. It was found that improvements in frost warning accuracy and reliability can lead to considerable savings and more efficient winter road maintenance.

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Application of Road Weather Information System (RWIS) for China is starting in an international perspective. However, the strong economic development during the last decades in China has caused a dramatic increase in the number of motorized vehicles, which calls for a quick development of RWIS and its application/services to safeguard the rapid development and to improve the safety of transportation. This study focuses on application of a winter index in China to quantify the need of a RWIS in different parts of China. The index is based on a concept related to various relevant weather parameters including ice, fog, snow, and wind. Its use is flexible in the sense that different types of inputs are possible, which is illustrated by a general view of the situation in China using climatological data and a case study using detailed meteorological data in Northern China. The results reveal that there are varying needs for RWIS in large parts of China. Regions with a great need for RWIS lie in the humid middle and northeastern parts of China. Some regions, however, may have a limited need for fully equipped RWIS stations. Such areas are the unpopulated areas in northwest or the dry regions in north. The results indicate that the introduced method provides useful information for China, both in the general view and in the case study.

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