Measures to Raise the Sophistication of Expressway Snow and Ice Management

Hokkaido Branch of East Nippon Expressway Co., Ltd. manages expressways for a total length of 632 km. Hokkaido is located at the northernmost part of Japan. In the jurisdiction, there are areas with more than 140 days of snowfall per year, an annual cumulative snowfall volume of over 1200 cm, and a lowest temperature of minus 30°C or more. In the winter season from 2009 to 2010, snow removal was conducted for a cumulative number of 5,273 times, and antifreezing agent dispersed for a cumulative number of 7,900 times. In other words, expressways are managed in the most stringent snow and ice area. Under those stringent meteorological conditions, the authors launched a series of programs to sophisticate their snow and ice management operations in the winter of 2009 so as to aim at efficient provision of safe and comfortable expressways. This report explains the process of four programs experimentally conducted as part of the effort for sophistication of snow and ice management, including (1) improvement of work efficiency by utilizing GPS-equipped vehicles (snow and ice vehicles and traffic control team vehicles), (2) collection of visibility information from the road condition image collection system, (3) collection of visibility information from the wide-area visibility information collection system using CCTV images, and (4) collection of snowfall information from the snowfall and snow accumulation automatic measurement system. Case examples of those measures are also introduced in this report.