More small and medium cities in the streets, mountains and rural areas have all been opened to traffic, they start from the economic benefits, but also the need for buses. Because buses not only adapt to big cities, but also more suitable for the streets of small and medium-sized cities, but also to adapt to the narrower road conditions, more suitable for people who travel relatively scattered mountains and rural areas. In addition, the owners hope that the full crew to increase efficiency, passengers want to leave on the train rather than wait a long time, and just a series of public transport to meet such a crowd.