Study On Urban Traffic Flow Allocation With Uncertain Road Congestion

The distribution of urban traffic flow is an important research problem.Existing research usually allocates traffic flow on a road network without congestion.Although some research considers traffic congestion,it is assumed that the location of the congestion is determined.In practice,the location of urban traffic congestion is uncertain,which brings great difficulties to traffic flow distribution.In this paper,the traffic flow distribution is carried out in two situations where the congestion of any road section is random and the road section is unknown.The main work and innovative results of the paper are as follows.Study on stochastic urban traffic flow allocation of road congestion.In the case of random congestion on any road section,considering that the occurrence of road congestion will cause the actual capacity of the road section to change,the actual capacity of the road section is introduced as a random variable into the road resistance function,and aim to minimize the expected travel time spent by the traveler.A random urban traffic flow allocation model for road congestion,and a genetic algorithm is designed to solve it,and finally a case analysis is carried out.The results show that,given the traffic volume at the starting point of the OD pair and the zero-flow time of the road section,the path with the smallest expected travel time under each OD pair can be obtained,and the expected travel time of each OD pair is the same,which can reach a state of User equilibrium.Research on urban traffic flow allocation with unknown road congestion.In the case of unknown road congestion,since the actual capacity of the road section is unknown,and using Profit method to calculate the actual capacity of congested road sections in different time periods.On this basis,using the theory and method of online problem and competition strategy,aim for as little travel time as possible for travelers themselves,establish the online assignment model of urban traffic flow with unknown road congestion,design the ONUE strategy of road congestion,analyze the execution effect of ONUE strategy in the two situations of monotonous increase of road resistance function and monotonous decrease of road resistance function,and prove the competitive ratio of the strategy.The results show that the competition ratios of the ONUE strategy for road congestion in the two situations are[(α*+β*)/2]g and[1+(α*+β*)·γ/2]g respectively,and through the example analysis,it is obtained that the ONUE strategy of road congestion has a better execution effect.