Careful consideration was given to the change in the snow-sliding performance of coated steel sheets roofs due to deterioration in snowfall area. Samples of the steel sheets that had deteriorated were collected from those actually used as roof coverings in Sapporo City.
As a result of these experiments, the dynamic friction resistance of those sheets which have been used for five years or more is on the upward trend. And no marked change can be found until fifteen years. After that, as irregularities on the outer surface increase, the above resestance has become much more larger.

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Durig winter in Niigata prefecture, the snowfall on the main streets and roads is cleared up by specially designed snowploughs. But the snow on the other roads is not always necessarily taken away. Some bridges across such roads where snow is not shovelled are likely to be damaged by the snow itself. Bridge handrails are especially subjected to such kind of damage.
The main purpose, of this study is to investigate how much load the snow-covered handrails will take up when the snow lies deep or melts. The results obtained from the field experiments caried out on the unshovelled road sections in Niigata can be summarized as follows
(1) The handrails are loaded by snow both in the vertical and in the horizontal direction while they are buried deep in the snow.
(2) When the snow melts, the handrails are twisted by the thowing force of the snow.
(3) The handrails in the snow underwent load reversals.

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Diffusion of studlesstires have almost completed in cold region in the winter of 1992. In proportion as studlesstires are come into wide use, road surface become slippery. And characteristics of winter traffic accidents are changing, as shown in the increase of slip accidents. For prevention of winter traffic accidents, of course, thoroughgoing countermeasures to road surface management are firstly neened. Furthermore it is necessary to improve road alignment to meet the changes of those characteristics. Also revising drivers' safety consciousness is needed to make up for countermeasures to road surfacemanagement in the circumstance when those countermeasures are still insufficient. This paper discusses countermeasures to road surface managements and road alignment and problems of drivers' sefety conciousness from analyses of characteristics of winter traffic accidents.

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