Rapid expansion of the transport sector inevitably leads to a surge of demand for energy, especially for oil products. From 1990 to 2004, the number of passenger vehicles and civil aircrafts increased by about 9 and 1.5 times, respectively (Table 4). The total number of vehicles increased over ten millions since 2000, over 80% of which is accounted by the growth of passenger vehicles. As for passenger traffic, vehicles and airplanes seem to be increasingly important in China, while the role of railways and waterways is declining (Table 5).