Research On System Dynamics Model Of Risk Transmission Of Traffic PPP Project

The PPP(Public-Private Partnership)model has received extensive attention in the field of public projects in China,especially infrastructure construction.As an indispensable aspect of infrastructure construction,traffic construction is one of the most widely used areas of PPP mode in China.Pushing China's current level of development to a new level.World Bank research shows that for every 1%increase in transportation facilities,GDP growth of 1%is caused.However,domestic transportation PPP projects have long-term,large-investment,and complex characteristics involving multiple parties,causing a wide variety of uncertain risk factors,resulting in cost overruns,time delays,and insufficient expected returns.Domestic and foreign scholars have conducted extensive research on the PPP model,from the initial concept and definition research to the risk management research.However,there are few studies on the systematic and related factors of the risk factors of the traffic PPP project.The traffic PPP project is a System engineering,comprehensive systemic risk management is a key part of the project's success.This study sorts out the research results of risk management of PPP projects,and finds that scholars are more inclined to study a certain risk stage or a single risk factor,ignoring the systemic of PPP projects and the cross-correlation of risk factors.The research results of card theory,system dynamics theory,engineering project risk management and PPP project risk management,and analysis and demonstration of the PPP project is a system that emphasizes the advantages of system dynamics in PPP project risk management.Through meta-analysis technology,this study reviews the relevant literature and analyzes the risk factors of high-frequency and representative PPP projects,and forms a risk index system and defines related indicators.Then establish the system dynamics causality diagram and deposit and flow map of the risk transfer of traffic PPP project,and finally form the"engineering quality risk subsystem","engineering delay risk subsystem","financing cost risk subsystem","construction cost risk" "PPP Project Risk Factor System" for Subsystem","Operational Cost Risk Subsystem",and "Expected Insufficient Risk Subsystem".In view of the weight between risk factors,this study combines subjective and objective weighting methods,comprehensively empowers risk factors,and constructs a system dynamics model for quantitative assessment of traffic PPP projects.At the same time,this study takes the Hangzhou Bay Bridge as an example.The system dynamics Vensim software is used to evaluate the target risk level of the project.The sensitivity analysis method is used to identify the key risks and risk paths of the project.The conclusion is:?The most important boundary risk factors for traffic PPP projects are legal change/imperfect risk,technical risk,market competition risk,material price increase,and climate/geological condition risk.? Five risk paths were identified for key boundary risks:"legal change/imperfect risk transfer path","technical risk transfer path","market competition transfer path","material price increase risk transfer path","climate/geology" Conditional risk delivery path.","material price increase risk transmission path","climate/geological condition risk transmission path".?Due to the correlation and transitivity of risks,the key boundary risks mainly affect the construction and operation cost risks,resulting in insufficient project expected revenue.Therefore,the focus of risk management is to control project construction and operation costs reasonably.Finally,a risk control strategy is developed for key risks and risk paths,and corresponding risk management recommendations are proposed.