Avalanche control measures for roads in Norway
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- NGI articles 
Original versionInternational Symposium on Snow and Related Manifestations. Manali, India 1994. Extended Abstracts
In a mountainous country like Norway the roads are exposed to different kind of natural hazards. Increasing traffic and extensive road-building programs the latest 25 years have made the society dependent on a relatively safe transport-systems with high regularity. These requirements are specially focused in the road planning process and in road maintenance. In avalanche protection we have invented special procedures for handling these problems according to the importance of the road, avalanche frequency and possibilities for alternative traffic routes. As avalanche caused accidents do not increase in the same rate as the traffic, the public have slightly changed their attitude about avalanches, from being dangerous to primarily cause regularity problems. This change of attitude has changed the prospective of avalanche control from focusing on the big slides, which often have low frequency, to the smaller avalanches with high frequency. To cut costs in avalanche protection, a search for the optimal location of the road and possibilities of using catching/deflecting dams to reduce the avalanche frequency have proved to be beneficial. Avalanche sensors connected to traffic control systems have also proved to give advantages in places where the path is long and the exposed road-length is relatively short. Tunnelling as avalanche protection is used extensively in Norway because of good rock quality and inexpensive building processes. Galleries have traditionally been designed for forces caused by worst case events. A prospective for the future is to use lower designing forces and more flexible solutions both for the shed construction itself and in the use of combined solutions between dams and galleries.