The Study On Road Charging Models Under Uncertain Emissions

With the gradually increase of the number of urban residents and the national consumption level,the demand for urban traffic increases rapidly.The traffic congestion and its negative external effects such as air pollution,traffic accidents,noise pollution intensified,seriously affecting the survival of urban residents' health,restricting the sustainable development of urban economy.Road toll is one of the effective means to alleviate urban traffic congestion and reduce exhaust emissions,and has received increasing attention.In this context,this paper uses the traffic planning theory,the uncertainty planning theory,the optimization theory and method,the operational research and the economics,and puts forward the pricing strategy of road pricing under the condition of uncertain discharge,aiming at adjusting the road network flow distribution status by charging,and reducing traffic demand to reduce vehicle emissions and improve the performance of the network for the purpose of scientific development of urban road toll and congestion control to provide a reference.First of all,the uncertainty of the vehicle emission data is analyzed and expressed.In this paper,the main factors influencing the emission estimation are taken into account,and the influence of extreme factors on the emission factors under extreme conditions is analyzed.The uncertainties of the emission factors are described by fuzzy numbers and fuzzy random numbers respectively according to the application in the model.In addition,the paper analyzes the uncertainty of the data of the road emission limit,and uses random fuzzy number to express,which will be used in combination with the traffic network design model.Secondly,based on the purpose of maximizing the total social benefits,considering the flow of fee funds,in this paper,the total cost of the whole road network is used to pay the cost of emissions in the road system.At the same time,combined with the multiple uncertainties of motor vehicle emissions,a bilevel pricing programming model with road emission budget based on link is established.The paper uses the combination of uncertain programming and numerical algorithm to transform the upper plan into the corresponding equivalence formula,and uses the sensitivity analysis algorithm to solve the bilevel programming.Taking experimental road network as an example,by changing the variable parameters in the model to analyze the main indicators of the changes and the relationship between them.Thirdly,the paper chooses the traffic congestion index as the standard of measuring the congestion degree of the road network.By deducing the method of calculating congested distance proportion,the minimum congestion level calculation model and congestion level constraint condition are established,which is used to predict the optimization potential of the road network and to manage the congestion degree.Based on this,this article from the perspective of different charging methods,combined with the uncertainty vehicle emission factor and the restrictions for the number of tolled links,respectively established under the uncertain emission factors conditions,the total emissions of the optimal system as the goal,the two stage charge mode and bilevel charging model based on link,and bilevel charging model based on the entrance point,the above model was solved by combining fuzzy stochastic programming,step acceleration method numerical algorithm and genetic algorithm are put forward.Then,taking the experimental network as an example,the optimization effect of the model is compared.Finally,the paper takes the main road network of the Second Ring Road of Beijing as the research example,further validates the emission reduction pricing model of the above two different charging methods,determines the congestion level restriction target by calculating the optimal congestion level of the road network,and discusses the expected congestion under the condition of the level of emissions optimization of the road charges and entry point charging program,and under different policy scenarios of emissions,congestion improvement effect of comparative analysis.The results show that although the mechanism of the two charging methods is different,the road system has significant effects on reducing total emissions and improving network performance.