An Approach To Analysis And Evaluation Of Highway Network Structural Properties For Risk Assessment And Emergency Management

Highway transport is an important part of the transportation industry. It plays an important role for passenger and freight transport and defense security.It supports sustainable development for national economy and meets the demand in high-quality travel for people. During "Twelfth Five Years Plan", the national highway network and the national and provincial trunk highway network are under construction, and the highway network and operational management will be undergoing profound changes. Frequent emergencies, such as natural disasters, bad weather, and severe traffic accidents and so on, have a significant impact on safety and transportation efficiency of highway network. A large scale "paralysis" can be caused in serious case. This will bring immeasurable losses of economic development, people’s lives and property safety.The current risk analysis methods and contingency management techniques are focused on segments level. However, they do not meet emergency management needs for cross-regional, large-scale, comprehensive coordination and scheduling under highway network environment, as well as for the management needs of future network scale and intelligent highway network operators.In practice, the balance and vulnerability of network structure and layout are the fundamental guarantee for the highway network safety and operation. The nature and structural risk of highway network are the basis of prevention and management of emergencies for highway agency, and the basis to make effective contingency plans. Currently, China is in a transition period from the segments management to network management. The theories and methods for operations and emergency management of the highway network are still lack. In this thesis, a series of theoretical analyses was carried out to investigate the risk assessment and emergency management of highway infrastructure. It is aimed to establish a theoretical basis and analysis method which are suitable for China’s highway network operations management and emergency management. The main contents are divided as followings:Firstly, the highway transportation network system is built up. The coupling relationship among the infrastructure layer, transport layer and management layer is illustrated. The scientific issues of highway network structure risk and emergency management are studied. The highway transportation network system and its characteristics, the relationship between highway network emergency and highway network structure, the relationship of highway network structure risk and emergency management, and the core problem of the highway network emergency management are analyzed. The standard process framework of highway network emergency management based on highway network structural characteristics and risk analysis is established. Path efficacy and efficiency are defined. The path efficiency optimal and shortest path route choice principle at emergency management are proposed.Secondly, from the structure and function of the highway network, the evaluation index system for highway network nodes and links local feature attributes importance and criticality and highway network global features properties are constructed, respectively. The evaluation indices suitable for nodes and segments of composite attribute importance and critical degree and its general model are proposed.Thirdly, the definition of critical nodes and segments of highway network and the classification standard are given. By using lexicographic method, a comprehensive evaluation method and reverse detection method, the new method for identification of critical nodes and segments are proposed. The identification processes is clearly shown.Fourth, highway network risk analysis and assessment methods are researched. By highway network vulnerability analysis, the highway network structure risk and its classification are defined. Assessment indicators and quantitative assessment method are suitable for highway network structure balanced risk. The balance of carrying capacity of key nodes and segments and the extent of the loss of network performance are proposed. A general model of comprehensive risk assessment of highway network structure is proposed. The methodology of highway network structure risk analysis is formed.Finally, a numerical simulation was conducted with data collected from the highway networks of five provinces and cities of eastern China (Shanghai, Zhejiang, Anhui and so on). It is verified to the correctness, reasonable and feasibility of highway network structural properties evaluation indicators and theoretical analysis method proposed in the study. Specific measures of structural characteristics and risks are suggested for the highway networks of five provinces and cities.