As cities are growing in terms of population and physical size, their contributions to national GDP are also increasing due to increased economic activities in urban areas. With this greater role of the urban sector, the demand for urban transportation – passenger and freight has increased many folds in the recent years. With the growth or urban economies, the living conditions and lifestyles of the city people are also changing. As income of the upper and middle class people in the city is increasing, the ownership of private vehicles is increasing rapidly. The Asian cities which do not have any growth management plan for controlling this rapid increase in personal vehicles are experiencing severe traffic congestion and other problems including air pollution, loss of personal and corporate productivity, high cost of transport and poor quality of life. Traffic congestion and air pollution have a negative impact on GDP as it imposes a significant cost in terms of both health and productivity. The traditional way of solving traffic congestion is to increase capacity of the road network. However, experience has shown that this solution only works as a temporary fix because developers build new commercial and residential developments where new lanes are added to an existing road network or where new roads are built. Consequently, after a few years, these roads become congested again. Most large cities in Asia have come to a stage where adding lanes or building new roads is not possible anymore due to scarcity of land. In addition, due to the increase in the price of construction materials it has become very expensive for cities to increase the capacity of the existing road network.
