Buses once served as a major means of transport for Chinese travelers. In recent years, due to the growing number of private cars, traffic problems in cities have become increasingly serious. In order to encourage more people to travel by bus, plenty of cities have been making efforts to improve bus service. Facilities in buses have been constantly upgraded, and the speed has been remarkably increased as well. The bus fare, however, still remains quite cheap. Today, in most cities, a large number of local senior citizens can take a bus for free.