A compact snow course fl~r winter tire evaluation is very difficult to maintain in a good and constant condition due to changeable weather, temperature, sunshine and surface conditions affecting the degree of snow compaction. In order to improve the test accuracy and the limited time of the test season, an indoor test machine with the inside face of the drum surfaced with ice was developed to evaluate tire performance on ice [1,2]. Using the geographical advantage of HNRI (Hokkaido National Industrial Research Institute) which is located in a district of high snow fall in northern Japan, we have developcd a method of evaluating traction on compact snow surfaces with an indoor testing machine. The evalualion methods, repeatability and correlation with vehicle tests on a snow-covered course are outlined below. Fresh snow is collected in winter and stored at about 15°C in a snow store room. The compact snow surface is prepared as outlined below. A uniform snow surface is prepared by gradually placing on the inside of the drum, and the surface is scraped by a surface scraping board. The snow surface is then compacted with the snow compaction tire. In order to avoid slippage between the compaction tire and snow surface, the tire is moved left and right at a speed of 0.07 c m / s while rotating the drum at low speed (below 1 k i n / h ) and low load (about 4 kN). The hardness of the snow surface at this stage is about 84 to 85, measured by a CTI compaction gauge. With further compaction, the surface becomes harder, and its hardness is determined bv the tire load, room temperature and length of compacting time. The hardness can be increased up to CTI Index 90.