TRIAL COUNTERMEASURES AGAINST POOR VISIBILITY CAUSED BY DRIFTING SNOW

摘要

Niigata Prefecture in north-western Japan, facing Sea of Japan, is one of the heaviestrnsnowfall regions on the earth for its geographical features; spine of mountains in winterrncapture much of icy clouds brought by north-westerly strong seasonal wind, which arernformed in the process of passing across the sea. East Nippon Expressway CompanyrnLimited, hereinafter NEXCO East, has carried out a series of addresses for approximatelyrn30 years to ensure the safe, reliable, and comfort service in winter months throughrncompiling kinds of manuals, developing snow and ice control facilities, making operationsrnmore efficient, providing traffic information to customers and so forth. Drifting snow andrnheavy snowfall, however, often reduces visibility, which forces expressways to be closedrneven in recent years. The cause by poor visibility occupies over 50% of all the closure timernand length; therefore, it is regarded as the one of the most urgent issues.rnThis paper describes the following points;rna) General winter conditions in Niigata and existing countermeasuresrnb) Trial approach by introducing a forecasting system for poor visibility and its outcomesrnc) Future direction.