The number of elderly and physically challenged people who fall down in buses is increasing in Japan. Therefore, we have used non-slippery and ecological flooring composed of quartz in a bus, since fiscal year 2004. Moreover, customers and bus companies were made to participate in the functional evaluation of the flooring. In fiscal years 2006 and 2007, we laid the new flooring in the buses of three bus companies under three conditions: non-rainy, rainy, and snowy. In each condition, about 80% of the customers gave a high evaluation for the non-slip function of the material. Moreover, we are able to obtain a high evaluation for the design and the compatibility of their shoes with the material. Nowadays, in the process of developing non-step buses, the 0.52 CSR value is used as a standard, in accordance with the rule of the Japan Auto-Body Industries Association, Inc. However, in this research, we introduced the best CSR value as flooring for universally designed buses. We recognized the CSR for non-step buses as 0.566. This value will be useful to the Ministry of Land, Infrastructure, and Transport in its formulation of a new floor standard in the process of developing non-step buses.