Research On Urban Dynamic Traffic Flow Assignment Under Combined Travel Mode

The research on urban dynamic traffic equilibrium for combined-mode trips has important theoretical significance and practical value.Some relevant studies are traffic equilibrium with travel demands uncertainty for pure-mode trips which are difficult to satisfy the actual needs of travelers who often choose two or more modes for combined-mode trips.Other studies are traffic equilibrium with travel demands certainty for combined-mode trips.Actually,the travel demands often change dynamically and cannot be determined.Therefore,this paper study on traffic equilibrium with demands uncertainty for combined-mode trips,considering the cases of road capacity certainty and road capacity uncertainty.The uncertainties are expressed as interval variables.In order to minimize each traveler’s own travel cost,the traffic equilibrium models with demands uncertainty for combined-mode trips are established under the condition of road capacity certainty and uncertainty respectively.Then the method of successive weighted average（MSWA）algorithm based on interval mathematics was adopted to solve the proposed model which can realize the results in form of interval variables.The main work and innovative achievements of this paper are as follows.The research on urban dynamic traffic equilibrium for combined-mode trips with road capacity certainty.We develop an equilibrium model with demands uncertainty and road capacity certainty for combined-mode trips,in order to minimize each traveler’s own travel cost.Travel demands is expressed as an interval variable.The interval method of successive weighted average algorithm based on interval mathematics was adopted to solve the proposed model with single interval impute parameter,which can realize the results in form of interval variables.Illustrative examples are also presented to demonstrate the characteristics of the model and algorithm.The influence of model parameters on traffic flow distribution is discussed and demonstrate that with the increase of the road network information perception coefficient,the selection probability of each travel mode is closer to the deterministic selection probability.The research on urban dynamic traffic equilibrium for combined-mode trips with road capacity uncertainty.We develop a equilibrium model with uncertainties of travel demands and road capacity for combined-mode trips,in order to minimize each traveler’s own travel cost.Travel demands and road capacity are expressed as interval variables.The interval method of successive weighted average algorithm based on interval mathematics was adopted to solve the proposed model with multi-interval impute parameters,which can realize the results in form of interval variables.Illustrative examples are also presented to demonstrate the characteristics of the model and algorithm.Compared to distribution results under the road capacity determination situation in Chapter 3 and the influence of the uncertainty of the road capacity on the allocation results is discussed that uncertainty of road traffic capacity causes uncertainty of distribution results to a certain extent.On the one hand,the uncertainty of the allocation results is increased,and on the other hand,the selection probability of each travel mode is greatly changed.