Studies on basic science issues of traffic congestion bottlenecks in large cities

The urban transportation system, as one of essentials of supporting human activities, makes great contribution to the rapid development of cities. However, most cities now are facing serious traffic problems, which largely affect the economy construction and operation efficiency. This brings various inconveniences and damages to people’s lives, and has become the main bottleneck hindering the sustainable development of cities. Such problems associated with backward transportation systems as traffic congestion, traffic safety and increases in environment pollution and energy consumption, have attracted the attention of various circles in the whole society.

A series of traffic problems are typically characterized by traffic congestion. The crucial point for alleviating and preventing congestion depends on comprehensively studying the travel demands and traffic flow dynamics, thereby exploring the generation and propagation process of different kinds of traffic bottlenecks, finding the origin of traffic congestion, and disclosing its evolution rules. All these will gain deeper insights into the evolution tendencies of traffic demands and networks constitute the theoretical basis for making scientific transportation planning, adopting efficient traffic control and management strategies and measures.

The key scientific issues to be solved in this project are as: 1) The patterns of generating traffic demands and the methods of identifying traffic bottlenecks; 2) The nonlinear dynamical characteristics of road flow; 3) The formation and propagation of network congestion; 4) The complexity of spatial-temporal evolution of transportation systems and the structural bottlenecks.

After four years hard work, the overall goal and expected contributions of this projects have been successfully accomplished. We have established the traffic flow theories suitable for Chinese conditions,  disclosed the running mechanism and evolution rules of transportation systems, found the measures of organizing, managing and controlling the systems for alleviating traffic congestion, developed the verification platform and practical software for carrying out traffic optimization, and proposed acceptable alternatives and applied them into reality for improving Chinese transportation systems. The extendable experiences obtained from this project have been summarized for further studies. The cooperative development of traffic science and traffic engineering has been adhered in this project. International-leveled research results, together with high-qualified research teams, have been expected. Our country’s capability of doing creative researches in the field of traffic science has been enhanced. All of these have certainly strengthened the capability of our country in self-confidently coping with the urban traffic problems encountered in future.