Optimization Of Dynamic Road Charging And Maintenance Strategies Based On Stochastic User Equilibrium

As the national economy steadily climbs and household incomes continue to rise,more and more small cars are entering ordinary homes.This significant increase in traffic demand poses a huge challenge to the construction,operation and subsequent maintenance of road traffic infrastructure.In addition,road users always choose the route that minimizes their travel costs,but road users do not have complete and timely access to road information.Therefore,this thesis addresses the problems of large investment,difficult management and inadequate technology in road construction,operation and maintenance by introducing the Public-Private-Partnership（PPP）model,which uses the principle of stochastic user equilibrium to rationalise the traffic flow of road networks.This thesis studies the optimization of dynamic road charging and maintenance strategies based on stochastic user equilibrium under the PPP model.A bi-level optimization model is developed for the case of fixed traffic demand.Firstly,the paper elaborates the research background and significance of the thesis and analyses the current status of domestic and international research.In addition,the paper describes the main research content,methodology and technical route of the thesis.The theoretical concepts and characteristics related to the PPP model as well as the reasons for introducing the PPP model are elaborated.Secondly,the bi-level optimization model proposed in this thesis is introduced,with the upper level planning for maximizing socio-economic benefits and the lower level being a stochastic user equilibrium allocation model.The upper level objective function and lower level objective function and their constraints are also elaborated.In addition,the thesis investigates the optimization of road charging and maintenance strategies with the objective of maximizing private sector profit,with the upper layer model considering only private sector profit and the lower level being a stochastic user equilibrium allocation model.In order to achieve sustainable and coordinated development of transport and the environment,the transport sector needs to take into account the consideration of environmental pollution while meeting transport demand.Therefore,the thesis also investigates the optimization of road pricing and maintenance strategies considering CO₂ emissions,where the objective function of the upper level planning model introduces CO₂emissions and the lower level remains a stochastic user equilibrium model.Thirdly,we analyse and study the algorithms related to the bi-level optimization model,and propose and introduce in detail the genetic algorithm used in the upper level of this thesis and the Method of Successive Algorithm（MSA）algorithm used in the lower level.Fourth,a case study is introduced to derive an optimization strategy for road tolling and maintenance of a small road network in Florida,USA,using the bi-level optimization model and algorithm proposed in this paper.The results are compared and analysed under three different optimization objectives.Fifthly,the optimization of road pricing and maintenance strategies considering CO₂ emissions.The objective function of the upper-level planning model is introduced to CO₂ emissions,and the lower level is still a stochastic user equilibrium model.The optimization results are also compared with the optimization results under the optimal conditions of the system.This thesis uses MATLAB software to solve the model using genetic algorithms and MSA algorithms to derive the optimization results.A theoretical basis is provided for decision-making by road users,the private sector and the public sector.