Metropolitan Transportation Infrastructure Carrying Capacity

Megacities often refers as the urban population of more than1million cities, especially as in a population of more than10million cities with large scale of economies and population size in the country and the status of the world’s highest megacities. As the central cities in the urban agglomeration in our country and the growth pole of regional development, megacities play an important leading and leading role at the national and regional development. The sustainable development of megacities is directly related to the stability of the region and the national economy and long‐term development. But megacities also face "city diseases" such as traffic congestion and air pollution. Especially the development of transport infrastructure in megacities cannot keep up with the speed of urbanization,leading the increase of the traffic cost,environmental cost and psychological cost, which become the limiting development factor of megacities.This paper choosing Beijing as the research object uses the methods of urban economics,regional economics and statistics to research the impact factors of traffic infrastructure and the mechanism of supply and demand. Then from the view point of regional function to the particularity of urban traffic infrastructure, the paper analyzes the current situation and problems of Beijing traffic infrastructure carrying capacity. In the end, learned from the experience of Shanghai and Tokyo, the paper makes relevant suggestions to improve the traffic infrastructure carrying capacity.