The regions along the Japan sea coast have continuous snow cover in winter as shown in Table I (Thickness of snow cover in the average year is indicated in the upper line and that in winter of 1951_??_52 in the lower line). In these regions, bus services are suspended for a certain period in winter. Examining the daily thickness of snow cover at 185 stations in the regions and date of suspension and reopening of bus services, the writer concluded as follows.
1) Bus service is generally brought to a standstill if the snow cover became thicker than 50cm and is reopened if it became less than 50cm. thick.
2) In case of busy routes, however, bus is served even though the snow cover is thicker than 50cm. In very busy, wide and paved roads, bus service does not come to a standstill even though the snow cover became thicker than 120cm. But in little frequented, narrow and bad roads, bus is not served throughout the snow-covered period.
3) In most of the comparatively warm but heavily snowing regions, snow fon the roads is removed by labourers in the early thawing season. In cold regions like Aomori prefecture and the northern part of Akita prefecture, only the snow on very busy bus routes is removed, and that on many other routes is left un-touched. Because, in cold regions, snow on the roads compactly settles as it increases in thickness, so sleighing and bus traffic are possible. But in comparatively warm regions, heavy transportation is impossible during snowy season, so the demand for transportation repidly increases in thawing season. Hence the necessity of removal of snow by many labourers.
